i have an 83 H/O with a late seventies 350 block. 30 over with edelbrock carb and intake, headman headers, and a decent cam though i do not know the size. it has the original seventies heads heads on it and im ready for more power. i believe the heads are whats choke the performance. now i found a set of 394548 c heads from 68-69 442. im told their the best flowing heads for a bb. now if i understand oldsmobiles,(my first and certainly not last) there was not a bb and sb. a 455 is a punched out 350 or 400 right? the way i see it is i may lose some compression but the heads will flow better. understand that i am currently staioned in germany and have the only hurst in town if not the country. getting a 455 is out until i get back but i need a little more power. a full restoration is planned with a bigger motor stronger trans and 12 bolt rear but thats not til oct 2011. im just tired of getting blown of the road by some kraut pos... please help

 

Don't do it. You will loose A LOT of compression and you'll need an Edelbrock performer RPM manifold to make it work.
What is the number on the heads 5, 6, 7, 7A, or 8? If you have 8s then try and find some of the lower number heads and you'll wake it up.

 

Their are lot of things different about those engines. The bbo has 1 inch taller deck height over a sbo. All the engines have different size pistons. The bbo has a longer stroke than the sbo. It's not a good idea to use bbo heads on sbo. If you want to buy them and save them for a bbo build that's ok. A 403 has bigger bore than a 455. Something like 5 are pretty good. Buy the way the F bbo heads are considered to be the best flowing bbo head.

 

so what heads should i look for for a 350? should i just enjoy it until it comes home? if thats the case what motor should i be looking at? i want reliability, and long life with 500+ horse. other than headers the motor must appear stock. all i need is the air cleaner housing and the original stamped steel valve covers.

 

So that is the best route for heads, and how much would they set me back I am trying to figure out how much I will be spending on all of this before I get home. So I can have a knowledge on what to expect or the range I will be paying if you get what I mean.

 

If they are infact Perimeter Bolt Heads, they are for 98 F-Bodies only.On second thought...if they are Perimeter Bolt Heads, then they probably are stock heads, since I dont think any aftermarket heads were made with Perimeter Bolt Patterns.