flamed 73

I'm interested in finding out the best heads to use on my 1973 olds 350 cutlass. It currently has stock #8 heads on it and I know lots of people have told me to use older #5 or #6 heads, but today somebody told me that big block olds heads fit them as well and suggested "C" heads. How much of a difference will it actually make in the end anyways....is it worth it? Or should I just get a big block 455cid motor, or even change to a chev big block 396 or 454 or something else all together, opinions would be appreciated

coppercutlass

I wouldn't use the bbo heads. Too much chamber unless you are doing a zero deck flat top build and too much runner volume . I would use the #5's if they are low milage or cheap and in good shape if not the procomps are all the rage now lol. It also comes down to your performace goals. I ran a 73 block stone stock with 7A heads with just a few bolt ons and tweaks ran 13.86 .

MDchanic

At the risk of performing the activity described by your handle, I must say that based on your post, the first thing you need to do is to learn a bit about engine design and function, and then decide what your needs and wants are for the engine in the car.

As Copper points out, combustion chamber volume, intake and exhaust runner volume, valve size, displacement, compression ratio, desired RPM operating range, desired fuel octane, intended use (street, strip, highway, etc.), desired fuel economy, and vehicle weight are all important factors to consider when putting together an engine.

You will need to tell us more before we can help you.

- Eric

olds 307 and 403

Milled Procomp or Edelbrock aluminum heads are the only BBO heads I would consider. Any 330 or 350 heads in good or rebuilt condition would boost compression and flow a bit. I would also run .011" shim or .028" composite head gasket, to maximize your gain.

flamed 73

I bought this car last summer, it is a complete driving 1973 cutlass supreme. I don't know the exact specs of the engine as it is, but it is gear drive timing with a fairly big cam, an edelbrock intake and demon 4 barrel carb, and has nitrous. I would just like to get a little more out of it but it is just a street car. I noticed that it has stock #8 heads and was only looking for some suggestions. Some people are quite willing to help and or make constructive suggestions and I do appreciate them as there are certainly a lot of informed oldsmobile guys here that could save me a lot trouble, others just take the opportunity to insult....thanks for nothin

1970-W30

How can asking for more information, so usefull constructive suggestions can be given, be considered a "thanks for nothing" insult?

flamed 73

Point Taken...thankyou

coppercutlass

So what are your goals . I would go with bbo to move that land barge.

olds 307 and 403

What piston's are in the engine? If they are flat top forged, 350 heads will put you over 10 to 1. If that is the case and the cam is large, then use the Aluminum heads for sure. What converter and gear? Stock you will be at 7.9 to 1, with the original head gaskets.

MDchanic

So you are driving a car with an engine that has probably had some kind of serious internal work. You just don't know what any of that work was.

Without knowing what sort of head work may have been done (were they milled, for instance?), what size valves you have, what kind of pistons, and what head gaskets and deck height, it is impossible to know whether different heads will help you or completely screw up your build.
The #8 heads on there may be modified, in which case switching to "better" heads may give you a worse result.


How much more? How much are you getting now? ETs? 0-60s? RWHP?


With a gear-drive cam and nitrous. Okay.


You're welcome.

Point taken.

Hope you get real good help after providing zero useful information.

Good choice of handle, though.

- Eric

coppercutlass

Flat tops with #8 heads will be under 10 to 1. Unleasss the heads have been seriously milled and the deck cut. #8 heads have 79 cc plus chambers

flamed 73

I would like to help more but I really know nothing about the internals, the guys plate was "I RUN 13" and he said it did. It is supposed to be 350 H.P. engine with a 150 H.P. single stage nitrous shot, it has 17 inch alloys with 4 wheel disc brakes. You can here the whine of the gear drive and it is a bit lumpy a idle. It also has a spooled rear end and dosen't like sharp turns. I have not tried the nitrous yet though there is some in the bottle. Maybe it would be best to just leave it alone? It does about 2800/3000 rpm @ 90kmh(56mph)

aretubj

Do you have the tubbed out red supreme?

Joe

67 Cutlass Freak

I think everybody here wants to help you. I agree more information was needed. I think you should go to the track to establish a base line. Tweek what you've got. Then try to improve on that. Which Edelbrock manifold do you have? The SB Victor is a different animal than the Performer or RPM performer. What size exhaust are you running and does it have headers? How fast do you want to go and how much money do you have? Is this your daily driver or are you going to tell us you want to get good gas mileage next? I have to agree with the others about using the BB heads. I specifically built a short block with dome top pistons for use with the BB heads. There is only a couple intakes that will work. Most do not have the roof material available to match port to the heads. I think you should ditch the gear drive and find out what cam you have in there. Some pretty big gains can be found by switching to a good roller cam as long as your top end can breath and all your components are properly matched. First you need to find out exactly what you've got. Can you contact the original owner to find out more of the engines blue print specs and what internal components were used? Were the #8 heads modified, (ported or milled)? Does your bottom end have any support, (studs, halo, girdle)? As long as it's running you may want to start building another high performance engine from the bottom up so you can continue having fun with your car. Build it at what ever pace your finances allows. If you do decide to build a BB the trans may not be strong enough to handle the extra torque. You should find a reputable Olds builder to help you. Pick up a copy of Bill Travatos book - "How to build a Performance Oldsmobile".