rcdynamic88

You guys here on CO have me looking at these Pro Comp heads for my SBO...I have a question about intake manifold choices, if there even are any options. On the eBay ad for Bernard Mondello's Pro Comp heads he has this in his listing:

Note: When using these heads on a small block Oldsmobile engine: 350-403 an Edelbrock 7111 aluminum intake manifold MUST be used. We also have this item available.

What is the reason for only the 7111 manifold? Intake port size? Could an Edelbrock OL4B from the past be port matched to the Pro Comp Aluminum heads?

olds 307 and 403

It has to do with port height, most SBO manifolds don't have enough material to cover BBO ports.

firefrost gold

The intake you are talking about can be had for not to much money if you dig around . The rmp is a good intake and unless you are trying to run the 70 -72 OAi I would go with the Rpm intake. The 68-to 69 style OAI will work with the Rpm with no clearance problems

joe_padavano

Yes, this is exactly the issue. I don't know if the OL4B has enough meat or not. Some factory iron manifolds also have enough meat to be port-matched.

oddball

The difference between BBO and SBO intake ports is the height, and it's all in the roof. Most SBO intakes only have enough material to cover the SBO head intake port, so putting them on an engine with BBO heads would leave a large gap at the roof of the port.
As far as I know, the Edelbrock RPM is the only one that has enough material in that area to cover the entire BBO port and can be ported to match the larger port.

firefrost gold

The victor also will work but is a high rpm beast .

OldSoldier

I'm interested in knowing what intakes will fit under an OAI hood for a 70-72 with procomp heads on a SBO. Hopefully someone has gone down that road before and can enlighten me.

joe_padavano

The carb flange on a stock SBO sits about 1.5" lower than on a stock BBO due to the shorter deck height, so you won't have near the problem fitting under the O.A.I. with a 350. In fact, the O.A.I. adapter on SBO cars uses a taller foam ring to make up the difference. If anything, you'd just need to use the BBO foam ring.

67 Cutlass Freak

Don't forget to make sure you tell the supplier that you will be using these heads on a SB. You will want to shave the head to get the combustion chamber closer to stock CCs. If you are planning on using a mechanical fuel pump, the head will need to be clearanced. Smitty can help you, or Bernard Mondello. Both are great guys to deal with.

bccan

AFAIK RPM & Victor are the only SBO intakes w/ enough material to port match the height of BBO port. I was just paying attention to this when I swapped on Street Dominator. The SD has just enough material on the OUTSIDE to cover the BBO port which iirc appx 3/8" - 1/2" taller than SBO port.

https://classicoldsmobile.com/forums...bbo-heads.html

There are some pics posted of BBO/SBO gasket comparison, post # 115

https://classicoldsmobile.com/forums...hniques-3.html