350 olds teardown and "refresh"

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Old December 12th, 2012, 12:46 PM
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350 olds teardown and "refresh"

okay, okay, I know before i even write this that i am going to be ridiculed lol! but bear with me. i have a 72 cutlass supreme. i am on a tight budget, and want to focus my money on the chassis and the body, but i also don't want to totally neglect the engine. (I already have a brand new interior; i am doing a frame off, and just finished refinishing the frame, and getting ready to begin installing the suspension and brakes.) it is an olds 350 from 1972 with 167,000 miles on it. i bought it from the original owner who was meticulous with maintenance and never abused it. i have done the same. when i pulled the engine from the car it ran very well.
i would like to take the engine apart, clean all the parts, paint all the parts gold that will be visible, replace all the gaskets, replace fuel pump, oil pump, water pump, alternator, etc, and all of the rubber hoses and metal fuel lines.
Eventually, when I am able to put more money toward this, I would like to rebuild the engine, but for now, this is my plan.
are there any shortcomings with this idea? any parts that should not be touched, or that should alsolutely be replaced?
thanks all so much in advance, i really appreciate all of your advice.
chris
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Old December 12th, 2012, 12:57 PM
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Answer a few questions first.
1 Was the engine rebuilt before you got it?
2 Did you check compression or the oil pressure PSI before you removed it ?
3 Did it leak or smoke ?
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Old December 12th, 2012, 01:23 PM
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Originally Posted by Oldssupreme
. when i pulled the engine from the car it ran very well.
Honestly, I would then just touch up the cosmetics and run it. If you seriously plan to rebuild it, why spend the money twice? Obviously, if there are oil or coolant leaks, fix those. You might just open a can of worms.

Meanwhile, pick up a 350 core, take your time and rebuilt it right. You can then sell your running 350 and swap in the rebuilt engine with very little down time.
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Old December 12th, 2012, 03:49 PM
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How long do you think it will be before you can afford to get it rebuilt? If it really did run well before you pulled it, I don't see why you couldn't continue to run it. I think it would be smart to do gaskets while it's out, that's easy. Cleanup and paint is no problem. If it's going to be a year or more before you can rebuild it and it's never been rebuilt before, a timing chain would be good to do also. Oil pump, fuel pump and water pump I would probably skip if you're only planning to run it for a limited time and you're budgeting for a rebuild anyway and could afford to be without it if something fails. Then, if the alternator, fuel pump or water pump fail, you could replace them as needed, and if the oil pump goes or something else lets loose, it's time to park it until you can rebuild it.
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Old December 12th, 2012, 03:55 PM
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I've done plenty of rattle can rebuilds. (clean up , paint and gaskets) If it had good compression , oil pressure and did not smoke then you will be fine.

I would put a chain set on it though.
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Old December 12th, 2012, 04:17 PM
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X2 on the timing chain and I would also put a water pump in it if I was that far in, reuse the pump on the next motor or rebuild....Tedd
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Old December 12th, 2012, 07:01 PM
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the car sat for about 5 years without being started, inside a garage. When my father and I attempted to start it by jumping, it caught the second time and ran on its own without holding the throttle. The exhaust was slightly white for about 30 seconds, and then was clear, no real strong smells, gasoline, or carbon. it was def not burning any oil. i decided to have it towed since i was moving an hour and a half from the garage where it was kept. when i started it again off the flat bed, it started right up and did not smoke at all.
the valve covers leaked some oil, as did the oil pan, but both at the gaskets. never had any issues with coolant leaking or going low, nor with oil.
unfortunately, i didnt think to test compression or oil pressure before i pulled the engine.
the engine has never been rebuilt, nor have the heads. only thing rebuilt was the Quadrajet carb.
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Old December 12th, 2012, 07:25 PM
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By the way, Gearheads, what do you mean by a rattlecan rebuild? A little paint and not much else?
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Old December 12th, 2012, 07:31 PM
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Originally Posted by captjim
Honestly, I would then just touch up the cosmetics and run it. If you seriously plan to rebuild it, why spend the money twice? Obviously, if there are oil or coolant leaks, fix those. You might just open a can of worms.

Meanwhile, pick up a 350 core, take your time and rebuilt it right. You can then sell your running 350 and swap in the rebuilt engine with very little down time.
+1 on what captjim said. If you're sure a rebuild is in the (near) future, I'd just change the bad gaskets, do a timing chain and water pump, clean her up real good and get a can or 2 of gold engine paint.
Start looking around for a block/core and have that done the way you want while you still have your car on the road. Swap the motors whenever you're ready. If the current motor is original to your car, you could even keep that and have that refreshed at your leisure or as $$ allows. It could be a great sales feature down the road should you decide to sell.
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Old December 12th, 2012, 07:43 PM
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Originally Posted by Oldssupreme
By the way, Gearheads, what do you mean by a rattlecan rebuild? A little paint and not much else?
as I said in my post
Originally Posted by gearheads78
. (clean up , paint and gaskets)
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Old December 12th, 2012, 07:49 PM
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Exactly. If it runs smoothly, that's a good sign. It's a little late to check oil pressure, so personally if I was going to build it later, I'd skip the oil pump now. The timing chain is on borrowed time as it's probably original. Since you're putting effort into it to run it for a while, it only makes sense to do this. Gaskets because it's easy with the motor out, and not a bad idea to do the water pump if you have the money. The MAWs (might as wells) can really take over here, so if you don't want to have to replace the fuel pump later, MAW do this, and the alternator, MAW... And don't forget about the vacuum advance canister. Or, you could address these as necessary or at the time of rebuild.

One other thing, I don't know how the other guys feel about this, but I wouldn't do anything much to "clean up" the inside of the engine, if you had this in mind. I'd be more concerned about dislodging junk. I one time "flushed" an old motor before an oil change. Changed the oil, took it for a test drive, oil pump failed, end of motor.
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Old December 13th, 2012, 05:59 AM
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Replace VC gaskets, checking top of head for sludge and valve seal pieces, clean oil drain holes. Remove exhaust manifolds, replace freeze plugs and gaskets. Replace pan gaskets and check oil pump pickup screen. Replacing the oil pump won't hurt anything. Replace timing chain and gears, water and fuel pump while you are there.
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Old December 13th, 2012, 06:14 AM
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Originally Posted by Intragration
... I wouldn't do anything much to "clean up" the inside of the engine, if you had this in mind. I'd be more concerned about dislodging junk. I one time "flushed" an old motor before an oil change. Changed the oil, took it for a test drive, oil pump failed, end of motor.
I'm with Mike If it ain't broke, don't fix it.

Clean the outside, new valve cover and oil pan gaskets, take a good look at everything, change timing chain, probably replace water pump while it's off anyway, put a nice coat of paint on it.

The deeper you go into a good-running engine, the greater your chance of upsetting the gods.

- Eric
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Old December 13th, 2012, 12:26 PM
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OK, thanks. One other thing i wanted to ask was about the head gaskets. I have heard that the new head gaskets are made from a thicker material than the old head gaskets were, and that by using these, the compression would drop. While in theory this makes sense, and if this is true, would there be that much of a significant drop in compression? If so, would it be a stupid idea to try and find a NOS head gasket, or would they be disintegrated after all these years?
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Old December 13th, 2012, 12:32 PM
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I wouldn't even pull the heads.
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Old December 13th, 2012, 01:04 PM
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why, too risky? opening a can-o-worms?
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Old December 13th, 2012, 01:18 PM
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I did exactly the same you are planning to do, replaced every gasket except for the head gaskets, cleaned and painted it and put it back in.
Guess what happened just a few days later...I had a blown head gasket and had to tear it down again.
Don't know if you have the same factory style steel head gaskets I had, but if so I would'nt hesitate and change them while you have the engine out of the car.
It's really annoying having to disassemble all the nice, freshly painted parts again...
Just my opinion, you might as well be lucky and your head gaskets are fine

Last edited by dancutlass; December 13th, 2012 at 01:21 PM.
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Old December 13th, 2012, 03:31 PM
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Originally Posted by Oldssupreme
why, too risky? opening a can-o-worms?
Yes, that's my opinion.

I always try to leave well enough alone - sometimes you just do one seemingly innocent thing and cause a major problem later.

Originally Posted by dancutlass
... just a few days later...I had a blown head gasket and had to tear it down again.
On the other hand, Dan has had an experience that argues in the other direction.

My personal feeling is that if the compression tests good, I would not mess with the head gaskets, especially since you will lose about 0.5:1 of your compression ratio when switching from original to "normal" aftermarket gaskets, but Dan's experience is valid, and it all depends on how you look at life.

- Eric
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Old December 13th, 2012, 05:24 PM
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Dan and eric,
You both have very valid points and i have been going back and forth... I think i would like to replace thhed gaskets as well, but 0.5:1 loss of compression is quite. Bit, especially when the 350 from 1972 was factory rated at 8.5:1! So is there the possibility that i can find a nos head gasket pair, or is there another manuafacturer that makes a thinner, but durable head gasket?
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Old December 13th, 2012, 05:35 PM
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i have a 1972 cutlass 350 i have owned since 1984 had about 80,ooo miles when i got it sometime around early 90s i pulled motor because coolant soft plugs were leaking . Did those and timing chain and gears and put motor back in now has 155,000 on it and runs great.
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Old December 13th, 2012, 05:40 PM
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Originally Posted by Oldssupreme
... is there the possibility that i can find a nos head gasket pair, or is there another manuafacturer that makes a thinner, but durable head gasket?
You might be able to find them.

As for other brands, Cometic makes a 0.027" thick gasket for $105, which is about 0.010" thicker than stock, but about 0.020" thinner than the "standard" FelPros.

You can plug in bore, stroke, piston dish, deck height, and gasket thickness and do the math for compression ratio changes.

- Eric
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Old December 13th, 2012, 05:44 PM
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Eric someone mentioned smitty at mj proformance had the or could get them . They can still be found it come down to sources. I bought a few sets but those im holding onto.
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Old December 13th, 2012, 06:08 PM
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Originally Posted by MDchanic
You might be able to find them.

As for other brands, Cometic makes a 0.027" thick gasket for $105, which is about 0.010" thicker than stock, but about 0.020" thinner than the "standard" FelPros.

You can plug in bore, stroke, piston dish, deck height, and gasket thickness and do the math for compression ratio changes.

- Eric
Eric, you are not confusing these with Corteco, are you? I believe they are still available in .028 for $60/pair +/-

Oldssupreme, your Cr with an aftermarket gasket will be around 8 to 1. Also, you are going to end up with $300-$400 in gaskets and other misc parts. If you TRULY are going to rebuild in the near future, keep that in mind. You might even be better off finding a running 350 or 403 for about the same amount ($300) and then rebuild your 350.
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Old December 13th, 2012, 06:27 PM
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Originally Posted by captjim
Eric, you are not confusing these with Corteco, are you? I believe they are still available in .028 for $60/pair +/-
Nope. That was a link to Cometic.

Corteco has a web site, but it is hard to navigate and search, and I couldn't find anything worth linking to.

- Eric
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Old December 13th, 2012, 06:43 PM
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Originally Posted by MDchanic
Nope. That was a link to Cometic.

Corteco has a web site, but it is hard to navigate and search, and I couldn't find anything worth linking to.

- Eric
I have also not had any luck with their site. Have you ever used the Cometics? It is my understanding that the head and block surfaces need a REALLY nice finish. Is that the case?
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Old December 13th, 2012, 06:49 PM
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Nope, I never have.

I'm more of an old-fashioned guy. In the distant future, when I finally get around to building my 350 and/or my 425, I plan to use the easily-obtained and relatively cheap FelPros and mill the heads accordingly to get back to stock specs.

- Eric
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Old December 13th, 2012, 09:07 PM
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If i have the heads rebuilt and milled, how much would they have to be milled to bring it back to 8.5 cr with the standard felpro head gasket? Would it hurt anything to have a bit extra milled off to create a 9.0:1 cr?
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Old December 14th, 2012, 05:37 AM
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Originally Posted by Oldssupreme
If i have the heads rebuilt and milled, how much would they have to be milled to bring it back to 8.5 cr with the standard felpro head gasket? Would it hurt anything to have a bit extra milled off to create a 9.0:1 cr?
Now you're getting into that can of worms, or those Might-As-Wells.

If you're going to mill the heads, you need to know where you are and where you're going.

You will need to cc the heads, since the nominal volume tends to be less than the actual volume.
You will need to measure the deck height, since it can vary significantly between engines.
You will need to measure the dish of your pistons (though it is not subject to as much variation within a given piston type).

Once you have that information, you can begin to figure out how much you would need to mill the heads to achieve your desired compression ratio.

The next problem is that stock Olds valves are not adjustable, so if you were to mill the heads more than a certain amount, you would need to use shorter pushrods to account for the reduced distance to the camshaft.

The next problem is that if you take enough off of the heads, your intake ports will no longer line up with your intake manifold. The solution is to machine that, as well.

You can see how this sort of thing can escalate.

Your simplest bet is to mill the heads for the difference between the stock head gaskets (about 0.014-0.016") and your replacement gaskets (probably about 0.046"), which would be about 0.030", which will put the head right where it was when it left the factory.

That's why I would say: Either rebuild it, or don't mess with the head gaskets in the first place.

- Eric
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Old December 14th, 2012, 08:41 AM
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Eric, and everyone else, thanks so much for your help, it has really been valuable. I am sure i'll be asking more of you guys. Thanks again!
Chris
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Old December 15th, 2012, 04:41 PM
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Ok, so let me ask this, lets say i was to simply put a new set of head gaskets in... If the compression was to drop to 8.0:1 from 8.5:1, would it be noticeable? Significantly, or marginally?
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Old December 15th, 2012, 05:26 PM
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Originally Posted by Oldssupreme
Ok, so let me ask this, lets say i was to simply put a new set of head gaskets in... If the compression was to drop to 8.0:1 from 8.5:1, would it be noticeable? Significantly, or marginally?
The stock cam is so mild (.400 and 194@.050, IIRC) that it will be fine.
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Old December 15th, 2012, 06:23 PM
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Thanks capt jim.
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Old December 17th, 2012, 11:05 PM
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My thought is everyone is right. It is up to you. One thought is its not broke don't fix it. On the other hand the factory steel shim heads are 40 some odd years old. Rust is something the factory gaskets tend to do.
In my opinion replace the gaskets, mill the heads. The factory gaskets are around .020, the replacements are around .040. Simple math says around .020 diff. So mill the heads .020, use felpro gaskets and be done. No problem with push rod size.
So in short , it is up to you. What does your gut say, what makes you feel good ,about the work you are going to do, in the end.

Gene
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Old December 22nd, 2012, 10:55 AM
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question..

If you go from stock heads to eddy rpm heads how thick are the gaskets on the eddy heads and will they lower your CR as well? with a .030" bore, speed pro flat tops, eddy rpm heads and manifold what will be the most likely CR I can get too?
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Old December 22nd, 2012, 04:18 PM
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Originally Posted by OldSchoolMuscle71
question..

If you go from stock heads to eddy rpm heads how thick are the gaskets on the eddy heads and will they lower your CR as well? with a .030" bore, speed pro flat tops, eddy rpm heads and manifold what will be the most likely CR I can get too?

You should probably start a new thread.
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Old December 22nd, 2012, 05:20 PM
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You need to know how deep the pistons sit in the bore,
How many "CC's" the pistons have,
How many "CC's" the heads have,
When you have all the info, you can figure what compression you have.
With all that info you can decide how far to deck the block and how much to mill the heads. You already know the fel pro gaskets are .040 thick.

I assume we are still talking small block Olds, if so the mechanical fuel pump will not fit.

Gene
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Old December 22nd, 2012, 05:43 PM
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yes small block. thanks for the info!
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Old December 22nd, 2012, 09:33 PM
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If you go from stock heads to eddy rpm heads how thick are the gaskets on the eddy heads and will they lower your CR as well? with a .030" bore, speed pro flat tops, eddy rpm heads and manifold what will be the most likely CR I can get too?
I just went through considering this (Ebrock heads) on my 350 Olds build for my 70 Supreme. Unless you are planning a build that will get your hp up around the 425 -450 range, with 10.5+ CR, & spinning it 6000 RPM+ you would probably be better off prepping a set of SB Olds iron heads (#5,#6, #7 etc).

The reason a 350 Olds build up of less than 400 hp would be BETTER suited to a small block iron head vs. an Edelbrock head is port volume of the intake runner. The Edelbrock head has a 188cc intake runner and a stock #5 head has a 152 cc intake runner. A ported #5 head would be around 165 ccs.

Here is a chart I found online on a chevy website:
PROJECTED HP PORT VOL.
MIN - MAX MIN - MAX
350 - 400 140 -160
400 - 450 160 - 180
450 - 500 180 - 200
500 - 550 200 - 220
550 - 600 220 - 230
600 - 700 230 +

The translation of this is as Ebrock heads intake runner (at 188 ccs) is designed for a 450+ hp build. Here's a qoute I stole from someone else (who knows much more than me) off one of the Olds websites that explains this very well:

"There's more to look at than just big flow numbers for a cylinder head. You must also look at the runner volume in cc's and the rpm and size of the motor being used. The Edelbrocks have a much bigger intake runner out of the box than any factory Olds head. My theory on heads is you need the smallest runner head the engine can use without becoming a restriction. Therefore velocity and maximum cylinder filling can be obtained. A large runner head (180 + ) on 350 motor will require a lot more rpm to pack the cylinder and make similar power than a small runner because it doesn't have the velocity due to it's large size."

So the bottom line is a 350 Olds motor built in the 350 - 375 hp range could produce more hp & ft lbs with a prepped iron head than Ebrocks because at the moderate RPM, CR, & power levels the larger port volume of the Ebrock head will have less velocity.

There seems to be lots of info online about having to mill the Ebrock heads to keep your compression up, having to use an RPM or Victor intake, and an electric fuel pump but very little written about the port volume. I'm no engine builder or expert but just discovered all this myself. Hopefully this info might help others with their decision for a 350 Olds build.

-Joe
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Old December 23rd, 2012, 05:07 AM
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At 350-375 HP, I wouldn't be looking at Edelbrocks anyway except for the cost factor and future gains.
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Old December 23rd, 2012, 07:02 AM
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Originally Posted by 380 Racer
At 350-375 HP, I wouldn't be looking at Edelbrocks anyway except for the cost factor and future gains.
I've seen many people on the Olds sites say they want to shoot for around 400 hp and go with the Ebrock heads on their 350 build. A lot of times the infamous Edelbrock 400/400 build will come up and the thought is to use the Ebrock heads instead of the #5 heads used in that build.

Going with the "you are going to spend almost as much to prep a set of iron heads, you can go a 1/2 point higher in CR, & you get the weight reduction of the aluminum heads" theory, intuitively it makes a lot of sense. For a BBO there doesn't seem to be any negatives to this. But for a 350 build you could apply the same theory and end up getting less power especially if you are going for a mild pump gas streetable build. The Horsepower TV 350 build is a perfect example at 384 hp. I know there have been many threads on that topic and why they ended up with such poor results but I think it at least shows it's possible you may have been better off porting a set of SB iron heads.

That said I'm sure at some point the Ebrocks would out perform the iron heads and you would be able to get the benefits of the lighter weight and additional 1/2 point of CR if you are running pump gas. The problem is that level might be further than most guys would go with their 350s.

You also have the dilemma of what to do with the port matching of the intake if you go with the Ebrocks on a mild 350 build up. For example would you port match the RPM intake to the Ebrock heads and decrease velocity even more? Would you NOT port match it and let the air slow down? Would you fill the floor of the Ebrock heads to decrease the port volume and increase the velocity? My best guess would be you would get the most benefit from filling the floors of the Ebrock heads for a mild build but you'd want the intake port matched for a build over 450 hp and spinning 6000+ RPM. These are issues you won't have to worry about with the iron SB heads and you don't have to worry about any of this stuff going with Ebrock heads on a BBO.
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