big block heads on small block

Old November 16th, 2009, 10:18 AM
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big block heads on small block

what type of performance or lack there of, with C heads on a 350 olds engine. thanks
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Old November 16th, 2009, 10:24 AM
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Stay with small block heads get some machine work done on them. Don't use the big block heads.
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Old November 16th, 2009, 10:36 AM
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They will physically fit, but it's not worth it unless you are doing major work to it. It would require new pistons just to get the compression back up to where it was and either a performer RPM or Victor intake due to the taller ports.
Like ^ said stick with the SBO heads. Have them ported and larger valves installed if they are small valve versions (most are).
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Old November 16th, 2009, 11:02 AM
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It can be (and has been) done in the past. As noted, the 80cc BBO chambers will drop compression, requiring new pistons to correct. Ports are larger, but this is only a benefit if you plan to run at high RPMs. Intake must be port matched to the heads. Only a few intakes have enough meat to do this. Performer RPM is one that will work.

Note that you can easily put the BBO valves in SBO heads.
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Old January 27th, 2010, 09:12 PM
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My dad has been running E heads on a 350 since 1978 and they work great. now granted there are somethings to you have to do to make that combo successful.

the motor has Jahn's semi-dome 12:1 pistons and has has the heads milled. Now he has to run 100+ octane to drive it since the heads were milled .01" he use to run Holley street dominator intake and had it port matched with a 780 holley and it ran good with an original W-31 (casting number 194) not an aftermarket W-31 cam. Now it has a Mondello cam .544 lift and then he went with a 950cfm holley 3 barrel and full polish and port job on the heads and lots of other goodies and it ran great. then now it has the offy low-rise dual quads with 2 500cfm elderbrocks.

Moral is the motor is balanced for 10grand and the cam setup and everything else is midrange to high range power. This is the power band he wanted and after a lot of researching and figuring out the best combos the big block heads work great with his combination.

So what I am trying to say is if you want your SBO to be a low to mid range power motor then NO to big block heads. But if you want a mid to high range motor and utilize the high revs of the 350 then BBo heads can be benefitial
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Old January 27th, 2010, 09:30 PM
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[=Oldsman71;143512] then he went with a 950cfm holley 3 barrel
[/quote]

So what did he do with the three barrel. Most people run a 4 barrel.
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Old January 27th, 2010, 09:37 PM
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it is put up in the garage for safe keeping. it is an awesome carb that most people don't know about.
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Old January 27th, 2010, 10:29 PM
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Originally Posted by joe_padavano View Post
Note that you can easily put the BBO valves in SBO heads.
How would you compensate for the difference in lenth?

John
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Old January 28th, 2010, 05:07 AM
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Originally Posted by Oldsman71 View Post
My dad has been running E heads on a 350 since 1978 and they work great. now granted there are somethings to you have to do to make that combo successful.

the motor has Jahn's semi-dome 12:1 pistons and has has the heads milled. Now he has to run 100+ octane to drive it since the heads were milled .01" he use to run Holley street dominator intake and had it port matched with a 780 holley and it ran good with an original W-31 (casting number 194) not an aftermarket W-31 cam. Now it has a Mondello cam .544 lift and then he went with a 950cfm holley 3 barrel and full polish and port job on the heads and lots of other goodies and it ran great. then now it has the offy low-rise dual quads with 2 500cfm elderbrocks.

Moral is the motor is balanced for 10grand and the cam setup and everything else is midrange to high range power. This is the power band he wanted and after a lot of researching and figuring out the best combos the big block heads work great with his combination.

So what I am trying to say is if you want your SBO to be a low to mid range power motor then NO to big block heads. But if you want a mid to high range motor and utilize the high revs of the 350 then BBo heads can be benefitial
So it's not balanced anymore if he revs it to 10,001? That's BS. Please do not give bad info. Balancing is not necessarily rpm specific.
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Old January 28th, 2010, 03:46 PM
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Originally Posted by Oldsman71 View Post
the motor has Jahn's semi-dome 12:1 pistons and has has the heads milled. Now he has to run 100+ octane to drive it since the heads were milled .01" he use to run Holley street dominator intake and had it port matched with a 780 holley and it ran good with an original W-31 (casting number 194) not an aftermarket W-31 cam. Now it has a Mondello cam .544 lift and then he went with a 950cfm holley 3 barrel and full polish and port job on the heads and lots of other goodies and it ran great. then now it has the offy low-rise dual quads with 2 500cfm elderbrocks.

Moral is the motor is balanced for 10grand and the cam setup and everything else is midrange to high range power. This is the power band he wanted and after a lot of researching and figuring out the best combos the big block heads work great with his combination.
Cough.......cough. I agree Mark this guy is clueless. That cam will never go anywhere near 10,000 rpms. The 3 barrell carbs were around in the late 60s early 70s and weren't worth a crap. The later HP series are a good carb tho. Either of those intakes need welding and then porting to work with BB heads. It can be done, but I'm not sure you have to wing the SB with the bigger heads either.
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Old January 28th, 2010, 07:18 PM
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i agree with 380 racer on this. you could use those big block heads but you will need higher compression pistons because the big block heads have larger chambers. 83cc i believe. If you do this you will also need a cam change to take advantage of that compression. The cheapest route would be to port the small block heads if more cfm is what your looking for. Unless you are going to be in the higher rpms its not necessary and if that is the case you will need a different cam anyway. little money=little performance
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Old January 29th, 2010, 04:49 PM
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Originally Posted by cutlassefi View Post
So it's not balanced anymore if he revs it to 10,001? That's BS. Please do not give bad info. Balancing is not necessarily rpm specific.
give bad info huh??????? why be a jerk?

the rotating assembly was balanced for 10 grand. we have the reciept from the machine shop.

a stock assembly balanced won't handle 10,000 so you are giving bad info.

But you read into what you want.

Last edited by Oldsman71; January 29th, 2010 at 04:59 PM.
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Old January 29th, 2010, 04:53 PM
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Originally Posted by 380 Racer View Post
Cough.......cough. I agree Mark this guy is clueless. That cam will never go anywhere near 10,000 rpms. The 3 barrell carbs were around in the late 60s early 70s and weren't worth a crap. The later HP series are a good carb tho. Either of those intakes need welding and then porting to work with BB heads. It can be done, but I'm not sure you have to wing the SB with the bigger heads either.

WTF??????? you have no idea what you talk about on the intakes. Unless you have personnally tried, you can't comment.

Also never said the cam was good to 10grand but what i did say was it was designed for mid to high range.
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Old January 29th, 2010, 05:10 PM
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No......it's WTF to you. Anybody that has seen the differences in the ports knows they won't work without major modifications. How do you know I haven't tried this already?
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Old January 29th, 2010, 05:18 PM
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the holley street dominator intake has enough material to be raised......got one sitting in the garage and the offy does too it is on the car. Being we have done it sucessfully without welding therefore I speak from experience. Whether or not you believe me, i could care less.

Last edited by Oldsman71; January 29th, 2010 at 05:44 PM.
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Old January 29th, 2010, 05:36 PM
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I HAVE done this swap before with the aforementioned Holley manifold, and if you want the ports to be close to matching, you NEED to weld it up. That is what I did, and was able to get a near perfect match, only after the weld.

The BBO intake port is about .300" taller, and the port in the head is right at the top of the manifold face.

Not welding this manifold really invites a gasket leak on down the road because there is not enough material to support the roof of the gasket.

For anyone doing this swap, you should get a set of Mr. Gasket 404's, and 405's, and put them up on the manifold face.

Do not forget you must open up one of the head locating dowels to fit them onto the block.

That being said, I loved the swap. I had a set of milled "E"'s on a 350 with flat tops, and a 224 cam with a 3.73 gear in a Trans Am, and this thing absolutely woke UP at 3000 rpm. With a stock converter, it would barely squeek the tires loose while power braking it, but it just plain hauled buttocks.
My experience,
Jim

Last edited by Warhead; January 29th, 2010 at 05:40 PM.
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Old January 29th, 2010, 05:42 PM
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Bottom line people is 455 heads WILL work and if you put together the right combo they will provide performance for you.

Anyone who has heard or seen The Beast, knows.

Last edited by Oldsman71; January 29th, 2010 at 06:05 PM.
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Old January 29th, 2010, 06:25 PM
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Talking

This thread is worthless without pics!!
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Old January 29th, 2010, 07:33 PM
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Originally Posted by Oldsman71 View Post
give bad info huh??????? why be a jerk?

the rotating assembly was balanced for 10 grand. we have the reciept from the machine shop. Then you have a machinist that's full of ****.

a stock assembly balanced won't handle 10,000 so you are giving bad info. I didn't say that. You said it was balanced for 10,000 rpm

But you read into what you want.
Tell you what, explain to me how you balance a crank and the whole rotating assembly then we'll go from there. Based on the statement you made you don't have a f..... clue how it's done and why. I've done hundreds, how many have you personally done?
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Old January 29th, 2010, 11:38 PM
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Originally Posted by cutlassefi View Post
Tell you what, explain to me how you balance a crank and the whole rotating assembly then we'll go from there. Based on the statement you made you don't have a f..... clue how it's done and why. I've done hundreds, how many have you personally done?
never said I did it so clean your eyeballs.

My dad took the engine to the machine shop and said balance for 10grand and they did that so maybe i can give you the car shop's phone number.
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Old January 29th, 2010, 11:41 PM
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you know what maybe the correct phrase is to handle 10,000 either way the motor will spin it.
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Old January 30th, 2010, 03:33 AM
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Originally Posted by Oldsman71 View Post
never said I did it so clean your eyeballs.

So why would you argue it then?

My dad took the engine to the machine shop and said balance for 10grand and they did that so maybe i can give you the car shop's phone number.
You can if you like, maybe someone here will call them, but I don't enjoy speaking with idiots.
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Old January 30th, 2010, 06:10 AM
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When you here a machine shop say BS that's when you know not to take parts to there shop. I going to give Oldsman71 a brake because he sounds like a young man.

I would say the machine shop only gave a big number because they knew the engine would never see that many rpms. I have heard BS like this from machine shops those guys are only worried about making money.

So if you could give the name of the machine shop so others will know who to stay away from. I don't like to see my friends get ripped off.

P.S. When I find a good machine shop I go back time after time. It's sad when a good machine shop closes or the owner retires.

Last edited by 70 cutlass s; January 30th, 2010 at 07:11 AM.
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Old January 30th, 2010, 07:07 AM
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I wouldn't doubt for a second he was told 10k. I've met some real arrogant speed shop guys, and lie right to your face engine builders. This thread reminds me of the days when Norm hung out here.
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Old January 30th, 2010, 07:12 AM
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Cool it guys this isn't ROP. Enough with the flaming. Any more and I will colse this thread.
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Old January 30th, 2010, 07:16 AM
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OK.... everybody take a deep breath!

It's possible to disagree without getting into personal insults. The purpose of this forum is to share information with each other. If you find yourself getting angry at a post take the time to have a cold drink and cool off before replying. The strength of this board is having lots of experience and different perspectives on the hobby we share. Lets keep it on a professional level to help not hurt others who enjoy these cars. John
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Old January 30th, 2010, 07:20 AM
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Originally Posted by mn71w30 View Post
i wouldn't doubt for a second he was told 10k. I've met some real arrogant speed shop guys, and lie right to your face engine builders. this thread reminds me of the days when norm hung out here.


lol!!!!!!!!!!!!!
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Old January 30th, 2010, 07:22 AM
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Originally Posted by 2blu442 View Post
OK.... everybody take a deep breath!

It's possible to disagree without getting into personal insults. The purpose of this forum is to share information with each other. If you find yourself getting angry at a post take the time to have a cold drink and cool off before replying. Good advice.
The strength of this board is having lots of experience and different perspectives on the hobby we share. Lets keep it on a professional level to help not hurt others who enjoy these cars. John
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Old January 30th, 2010, 01:53 PM
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Originally Posted by citcapp View Post
Cool it guys this isn't ROP. Enough with the flaming. Any more and I will colse this thread.
Sorry, but if someone comes on here spewing BS ROP style......guess what happens?
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Old January 30th, 2010, 05:34 PM
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Theres always a couple bullys on every playground.
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Old January 31st, 2010, 05:03 AM
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Originally Posted by Eightupman View Post
How would you compensate for the difference in lenth?

John
Most Olds V-8 valves are in the ball park of 4.7 inches long, the longest (350 cu in 1.875 intake valve, years 68-72) at 4.74 inches, and the shortest being 4.667 (400, 425, 455-2 inch valve from 68-mid 70's).
It is not difficult for a good, experienced cylinder head grinder to get these to work in other engines if you take some time to do it right.
All of these engines have a set up height that is published yearly (most shops hoard THAT information as if were gold, they do PAY for those numbers), and it is not too hard to get the tip where you need it to be.

Remember, Nick, Mark...if we were doctors, we would need to be accountable for a "bed side manner", so to speak. I too, come off way too grouchy at times, and I am just as bad.
The 10000 rpm comment was probably his dad's slang for "do it right, please-I am going to beat on it" and over time, been taken WAYYYYY out of context. Most factory balance jobs are to a 2 gram tolerance. Fine for 5-6000 rpm's, not for 10 (as if an iron crank, rods and block would ever make it that high in one piece). I have never balanced any crankshafts, so what do I know. Take THAT as you want, but no reason to beat a dead horse.

There is no doubt that his Father put this together as best as HE knew at the time, and if Oldsman wants to update to a Perf Rpm manifold, I am willing to assist, if he wants it port matched. Pm. me if need be.

Jim

Last edited by Warhead; January 31st, 2010 at 05:31 AM.
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Old January 31st, 2010, 05:12 AM
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Originally Posted by MN71W30 View Post
Theres always a couple bullys on every playground.
So you think I'm a bully? Now that's funny!! LOL
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Old January 31st, 2010, 06:20 AM
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Originally Posted by Warhead View Post
Most Olds V-8 valves are in the ball park of 4.7 inches long, the longest (350 cu in 1.875 intake valve, years 68-72) at 4.74 inches, and the shortest being 4.667 (400, 425, 455-2 inch valve from 68-mid 70's).
It is not difficult for a good, experienced cylinder head grinder to get these to work in other engines if you take some time to do it right.
All of these engines have a set up height that is published yearly (most shops hoard THAT information as if were gold, they do PAY for those numbers), and it is not too hard to get the tip where you need it to be.

Remember, Nick, Mark...if we were doctors, we would need to be accountable for a "bed side manner", so to speak. I too, come off way too grouchy at times, and I am just as bad.
The 10000 rpm comment was probably his dad's slang for "do it right, please-I am going to beat on it" and over time, been taken WAYYYYY out of context. Most factory balance jobs are to a 2 gram tolerance. Fine for 5-6000 rpm's, not for 10 (as if an iron crank, rods and block would ever make it that high in one piece). I have never balanced any crankshafts, so what do I know. Take THAT as you want, but no reason to beat a dead horse.

There is no doubt that his Father put this together as best as HE knew at the time, and if Oldsman wants to update to a Perf Rpm manifold, I am willing to assist, if he wants it port matched. Pm. me if need be.

Jim
Well put. In reality, how many Olds engines (even guys like Bill, Andy, Russell, Art, etc) ever see ten grand? We just don't have the heads for it.

We try to get street balance jobs just under 2 grams as you stated and competition jobs at .5 gram.
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Old January 31st, 2010, 06:37 AM
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Well put captjim and Warhead. I know I have never built an engine that turned ten grand. Even when I ran Chevy engines most I every had one up to was 7,500. The cost of building an Chevy engine to run in that ten grand rpm range was out of my price range.
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Old January 31st, 2010, 07:03 AM
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Want to talk about a pain in the ***? Put BB heads on a small block!

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Old January 31st, 2010, 10:25 AM
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That only applies to Edelbrock BBO heads. The stock iron BBO heads have the "dimple" in them for the pump.
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Old January 31st, 2010, 10:38 AM
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Originally Posted by z11375ss View Post
Want to talk about a pain in the ***? Put BB heads on a small block!
I see the need...the need for a blow proof bell
housing.
Looks like a BLAST!
Jim
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Old January 31st, 2010, 08:12 PM
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Originally Posted by Warhead View Post
There is no doubt that his Father put this together as best as HE knew at the time, and if Oldsman wants to update to a Perf Rpm manifold, I am willing to assist, if he wants it port matched. Pm. me if need be.

Jim
The motor was rebuilt back in 96 but before that was 78. The motor was built with help from Dick Miller and Joe Mondello and it is a damn strong running motor.

Far as the RPm manifold no thanks this setup is working just great with the E heads.



Next time I am down at my dad's I will get a pic of the holley manifold and do some comparision pics.
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Old January 31st, 2010, 08:19 PM
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Oldsman71, nice looking engine compartment. Do you have more photos of your car posted elsewhere? Most of the time new members are asked to post pictures of their cars so we can all enjoy them. If that hasn't happened yet would you create a new thread showing us your car and telling us more about it? John
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Old January 31st, 2010, 08:29 PM
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Originally Posted by 2blu442 View Post
Oldsman71, nice looking engine compartment. Do you have more photos of your car posted elsewhere? Most of the time new members are asked to post pictures of their cars so we can all enjoy them. If that hasn't happened yet would you create a new thread showing us your car and telling us more about it? John
I just added pics in my album. I will upload more tomorrow when I get my other computer up and running.
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