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Old July 7th, 2018, 02:24 PM   #1  
Kyle
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My Engine Rebuild

It is an Oldsmobile 350. 7A Heads.

Definites:
Sealed Power Flat Top pistons.
Edelbrock Dual Plane Performer RPM intake manifold.
Will go with the Rochester Quadrajet.
Double timing chain.
Performance water pump and oil pump.
I believe I will go with the original rocker arms and valves, just clean the valves real good.
No head work, although maybe I will just sand down the exhaust side.
Headers.
Question:
The main question is what camshaft to use to optimize this for maximum horsepower and torque. I definitely want to go hydraulic roller, I think it is worth it. Is duration 262/268 with .505/.505 lift too much? This is what I'm referring to: http://www.compcams.com/Company/CC/c...csid=1182&sb=2

Any other recommendations or input is appreciated.

- Kyle
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Old July 7th, 2018, 03:47 PM   #2  
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I assume you have 1972 vintage 7A heads and not the 1980s 307 7A heads. Put your money into the heads if you want to make power. Large valves like a W-31, for example. Spending money on a cam is wasted unless the heads are also improved.
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Old July 7th, 2018, 04:33 PM   #3  
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So my machine shop gave me a quote for around $800 for head work. I assume this means port and polishing?? Can you tell me some other types of head work and I'll do my own research into it?
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Old July 7th, 2018, 04:36 PM   #4  
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Any reason you want 10.5 to 1 compression? Why not see if Mark can get you the Mahle 10cc dish modern pistons.
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Old July 7th, 2018, 05:40 PM   #5  
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So my machine shop gave me a quote for around $800 for head work. I assume this means port and polishing??

Highly unlikely. I recently paid $1100 for a stock-ish valve job on a set of Olds heads, though that included installing hardened seats on the exhausts, new big valves, and machining for teflon seals.



The days of $400 valve jobs on a pair of V8 heads are long gone...
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Old July 8th, 2018, 04:16 AM   #6  
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With that cam I would say no more than 9.5 to 1 compression, you should get a few quotes on the engine rebuild. You can get a set of speed pro aluminum heads for 1300.00. I paid 300.00 for a head job including clearance for a small cam, .499 lift . An olds engine rebuild should only cost around 600.00 more than a SBC, mainly due to parts costs. Any good machine shop can rebuild any GM engine. If you want to daily that engine you will want 8.5 to 9 to 1 compression in reality. Drop the roller cam to save 1000.00, just prime and use the right fluids or have the machine shop run the engine in for you.
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Old July 8th, 2018, 05:42 AM   #7  
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With that cam I would say no more than 9.5 to 1 compression, you should get a few quotes on the engine rebuild. You can get a set of speed pro aluminum heads for 1300.00. I paid 300.00 for a head job including clearance for a small cam, .499 lift . An olds engine rebuild should only cost around 600.00 more than a SBC, mainly due to parts costs. Any good machine shop can rebuild any GM engine. If you want to daily that engine you will want 8.5 to 9 to 1 compression in reality. Drop the roller cam to save 1000.00, just prime and use the right fluids or have the machine shop run the engine in for you.
Now is that 1300 each? And are they already designed for good flow? Because I know Edelbrock has some heads but they are 1100 for just 1! I was considering not doing the roller cam after all your guys' replies. I think I will go with machining the heads instead. Plus: I've heard 3.73 gears can make as much a difference for speed as a cam, and those are pretty cheap in comparison.
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Old July 8th, 2018, 05:44 AM   #8  
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I assume you have 1972 vintage 7A heads and not the 1980s 307 7A heads. Put your money into the heads if you want to make power. Large valves like a W-31, for example. Spending money on a cam is wasted unless the heads are also improved.
I know it would be expensive but are you saying that technically through machine work I can make my heads flow super similar to W-31 heads? I don't know much about the W-31 but it seems to be held in really high respect.
And yes 1972 7A.
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Old July 8th, 2018, 07:32 AM   #9  
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http://oldsrocketparts.com/index.php...luminum-heads/

http://oldsrocketparts.com/index.php...-top-end-kits/

https://www.jegs.com/i/Speedmaster/7....2152/10002/-1


I always shop around like crazy. I said pro comp but I think they are now speedmaster, The oldsrocket heads are direct bolt on and only 69cc or 80cc, pretty sweet.
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Old July 8th, 2018, 08:20 AM   #10  
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http://oldsrocketparts.com/index.php...luminum-heads/

http://oldsrocketparts.com/index.php...-top-end-kits/

https://www.jegs.com/i/Speedmaster/7....2152/10002/-1


I always shop around like crazy. I said pro comp but I think they are now speedmaster, The oldsrocket heads are direct bolt on and only 69cc or 80cc, pretty sweet.
You better check those stated cc’s. There are already some that have received heads with an incorrect chamber size.
Roller cams are not really compatible with the stock type valvetrain, wouldn’t recommend it.
And if you’re unsure of what’s included for $800 price the shop gave you then ask, and get it in writing.
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Old July 8th, 2018, 09:32 AM   #11  
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The Procomp heads are around $1300 for a pair with quality parts and proper clearances from someone like Bernard Mondello. He will only take the chambers to the 70CC, it is what he told me, probably a personal preference. The W31 was a 10.5 to 1 Olds 350 with 2"/1.625" valves, stiff springs, 308/308 .474/.474 cam and a huge harmonic balancer. Add a special Qjet, ram air, special calibration auto or 4 speed with steep gears, made a potent car. It was under rated at 325 gross hp, actually put out 350 or 360 gross hp.
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Old July 8th, 2018, 10:07 AM   #12  
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The Procomp heads are around $1300 for a pair with quality parts and proper clearances from someone like Bernard Mondello. He will only take the chambers to the 70CC, it is what he told me, probably a personal preference. The W31 was a 10.5 to 1 Olds 350 with 2"/1.625" valves, stiff springs, 308/308 .474/.474 cam and a huge harmonic balancer. Add a special Qjet, ram air, special calibration auto or 4 speed with steep gears, made a potent car. It was under rated at 325 gross hp, actually put out 350 or 360 gross hp.
Huh. That's interesting, maybe I can ask the machine shop to machine it so I could use those valves. I assume hydraulic flat tappet. And looks to be that the harmonic balancer is just over 7 inches? Anyone know where I could buy one of those or the significance of that (what does it do performance wise)? Just a thought.
- Kyle
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Old July 8th, 2018, 10:35 AM   #13  
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A couple years ago at "Street Machine Nationals" in St. Paul, Minnesota, I saw what was supposed to be a 68 or 69 W-31 on the chassis dyno. It pulled 344 HP, and it wasn't a fresh motor because some "blue smoke" came from the exhaust pipes. NHRA originally factored them to 350 HP, back in the day.
The factory .308/.308, .474/474 cam was a good one. I think they used the same cam in 1966 to 1969 4-4-2 W-30's and 68-69 W-31's and 1968 H/O (without A/C).
Remind me later and I'll try to find an old magazine article about W-31's that you can print out and read. I believe that a blueprinted W-31 ran 12.20's 50 years ago.
Perhaps you can Google "Rich Powers W-31" to find it. I think all the info then will translate to today.
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Old July 8th, 2018, 02:25 PM   #14  
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The Procomp heads are around $1300 for a pair with quality parts and proper clearances from someone like Bernard Mondello. He will only take the chambers to the 70CC, it is what he told me, probably a personal preference.
Not sure why he would only take them to 70cc. I've milled more than a few sets of Procomps to 60 and below.
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Old July 8th, 2018, 02:38 PM   #15  
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Huh. That's interesting, maybe I can ask the machine shop to machine it so I could use those valves. I assume hydraulic flat tappet. And looks to be that the harmonic balancer is just over 7 inches? Anyone know where I could buy one of those or the significance of that (what does it do performance wise)? Just a thought.
- Kyle
The balancer is expensive and not necessary. The reasoning behind it was higher RPM Olds knew people would spin the W31 too. Yes the cam was hydraulic.
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Old July 8th, 2018, 02:41 PM   #16  
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Not sure why he would only take them to 70cc. I've milled more than a few sets of Procomps to 60 and below.
I believe you Mark and that was when the chambers were measuring 84cc. Still should be plenty thick, maybe worrying about intake fitment? Just his comfort level, is what I got from the conversation.
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Old July 9th, 2018, 03:21 AM   #17  
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Well those heads look like a good deal, and they're aluminum. I saw them at the beginning of my rebuild while still just perusing parts. Would I be able to reuse the valves, rocker arms, and pushrods? And from a company with the name Bernard Mondello Racing, I'd assume they're already performance machined "enough". I'm still beginner so I don't understand the significance of what Mark was saying. But it seems that smaller volume would be more compression, but I'm already pushing it with daily compression?
Sorry for my ignorance.
- Kyle
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Old July 9th, 2018, 06:14 AM   #18  
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I would keep compression below 10:1 for sure, I had 9:8 to 1 with iron heads and went down to 9.3 :1 and still have the timing dialed back pretty far in the summer with premium fuel. 8.5 :1 - 9. 1 would be better for me. You first decide what compression you want and then go from there. You can run a little higher compression with a cam with more valve overlap, but the combo has to be just right.
I was new to engine building a year ago and if I had to do it again I would just mill mill heads to 64cc or lower, slap in some new cast pistons and put a mild RV cam with headers and 4bbl thats it, keep it simple and low cost. When you start looking at big cam, big heads lots of other parts are stressed, valve springs need more pressure, which means all the hardware needs beefed up, then the cam has more pressure and can wipe a lopes easier, more compression is more stress on the bottom end bearings etc. etc.
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Old July 9th, 2018, 06:18 AM   #19  
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With either the Edelbrock or Procomp heads, you need aftermarket rocker arms, screw in 7/16" studs, guide plates, different length pushrods and a electric fuel pump along with a block off plate where the mechanical fuel pump sits. The electric fuel pump is needed because the edge of the head over hangs the block. You can use stock rocker arms and pushrods with your 7A heads, just keep lift around .500". Problem is the faster roller cam ramps require more spring pressure requiring similar parts installed in the 7A heads. You should also get a roller cam with more lift the.505". The cheapest solution, while still gaining some performance, is a flat tappet cam, have the machine shop install 2"/1.625" valves in your 7A heads and have the bowls opened up with a bowl hog cutter to take advantage of the bigger valve. Hand blending with a grinder improves flow more, if done right. Even the larger valves and the bowls cut bigger adds about 30 cfm, around 210 intake, Procomp heads flow 240 cfm but have larger ports as well and need the Performer RPM intake. The Procomp being aluminum and have a superior spark plug position should allow more compression without pinging. Of course you will run more cam with those heads anyway. I am also plan on a roller cam next time, I can have more lift, better vacuum, decent economy and more power.

Last edited by olds 307 and 403; July 9th, 2018 at 06:24 AM.
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Old July 9th, 2018, 06:58 AM   #20  
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With either the Edelbrock or Procomp heads, you need aftermarket rocker arms, screw in 7/16" studs, guide plates, different length pushrods and a electric fuel pump along with a block off plate where the mechanical fuel pump sits. The electric fuel pump is needed because the edge of the head over hangs the block. You can use stock rocker arms and pushrods with your 7A heads, just keep lift around .500". Problem is the faster roller cam ramps require more spring pressure requiring similar parts installed in the 7A heads. You should also get a roller cam with more lift the.505". The cheapest solution, while still gaining some performance, is a flat tappet cam, have the machine shop install 2"/1.625" valves in your 7A heads and have the bowls opened up with a bowl hog cutter to take advantage of the bigger valve. Hand blending with a grinder improves flow more, if done right. Even the larger valves and the bowls cut bigger adds about 30 cfm, around 210 intake, Procomp heads flow 240 cfm but have larger ports as well and need the Performer RPM intake. The Procomp being aluminum and have a superior spark plug position should allow more compression without pinging. Of course you will run more cam with those heads anyway. I am also plan on a roller cam next time, I can have more lift, better vacuum, decent economy and more power.
Yeah that's a pretty hefty bill. I guess I should just go with the 7A heads I have. I have the Performer RPM. Thanks for all the input. One thing I don't understand though, COMP Cams says that the flat tappet require more maintenance than roller, what maintenance does a camshaft require?

And the factory cam 308/308 .474/.474 is only 135 on Summit!! Although just read it will make my brakes not work too well? Anybody own or driven a W31 and can comment?

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Old July 9th, 2018, 07:18 AM   #21  
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Just a zinc additive or oil with zinc in it, plus the break-in is more involved. Thats is no big deal. The break-in is the hard part, with higher spring pressures some recommend break in springs, running valves loose on break-in. I broke in 2 Lunati cams with next stage from stock springs with no problems, full new spring pressure was applied. I think if once you get more than that you need to take more pre-cautions.
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Old July 9th, 2018, 07:41 AM   #22  
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Just a zinc additive or oil with zinc in it, plus the break-in is more involved. Thats is no big deal. The break-in is the hard part, with higher spring pressures some recommend break in springs, running valves loose on break-in. I broke in 2 Lunati cams with next stage from stock springs with no problems, full new spring pressure was applied. I think if once you get more than that you need to take more pre-cautions.
Ah, okay i was just concerned that maybe I would have to do some obscure maintenance that would require me to take it out and put it back in. Sounds simple enough.
Thank you, all of you guys have been really helpful.
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Old July 9th, 2018, 08:14 AM   #23  
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The W31 cam is pretty radical, power brakes will be marginal. Also with 10.5 to 1 compression and a big cam, 2500+ stall and 3.55+ gears will be necessary. There are modern flat tappet cams with more lift, better vacuum and similar performance, contact Cutlassefi. I still say a small dish piston is the way to go but it depends on what you want for manners and where you drive it.
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Old July 10th, 2018, 02:49 PM   #24  
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Just to be clear for small block engine use, we have done both our SpeedMaster and Edelbrock aluminum cylinder heads as small as 60-64 cc's...

Thank you in advance,
Bernard Mondello Racing Enterprises, Corona, California. 951-371-1432
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Old July 11th, 2018, 06:28 AM   #25  
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Thank you for clearing that up Bernard.
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Old July 11th, 2018, 02:37 PM   #26  
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No problem!

You're welcome olds 307 and 403...

Thank you,
Bernard Mondello
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Old July 11th, 2018, 04:32 PM   #27  
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Ugh! My cam bearings cam in the mail today, and they came from the same factory as my timing chain. They were both put in a bag, and both of the boxes crushed and opened inside! Now the bearings are all scratched and gouged up!!
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Old July 11th, 2018, 05:07 PM   #28  
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Call and get a refund. Make that DEMAND a refund.
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Old July 11th, 2018, 05:31 PM   #29  
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Call and get a refund. Make that DEMAND a refund.
Yeah it's just a hassle I don't know why they'd do something like that. All the other packages were packed perfectly. And It is just inconvenient because I don't think they have a phone number.

Well that was actually pretty easy. I don't have to return them and they already shipped new ones out.

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