Ok so i was going to go with aluminum aftermarket heads for my olds 350 engine but i think i might go ahead and get some head work done to my factory heads instead. My question is does anyone know what the factory combustion chamber cc's were for a 1973 olds 350 engine on the #8 heads? Thanks in advance.

 

Hello 1973oldsomega, here's the link to the wiki page that talks about cc in small block heads.

http://www.oldsmobilewiki.com/index....eads#Details_2


It shows the #8 as having the most of the 350 engines. I don't know a lot about the small blocks as I got into the 455's a long time ago and am partial to them. But it sounds to me like you would be ahead of the game if you got a set of older castings to work with. If you decide to do that please post your location with your parts wanted ad. Shipping can really add to the price if your shipping across the country. John

 

I replaced my #8 (79cc) heads with a set of 7a (64cc) heads on the 350 in my 75 Supreme. Along with a cam change, and a few other things, it really woke the old gal up.

Brad

 

#8 heads do have a place in Olds performance, IMO. One issue we have is the lack of piston selection. If you are going to replace the pistons with either a flat top or a small relief piston (Speed Pro or Probe) the larger chambered #8 head will yield a compression ratio that will allow you to run pump gas, where the older heads will bump it up into the mid 10's, too high IMO. So, what are you piston plans?

 

Edelbrocks (77cc and big valves) were designed for use with the 455. Not the best choice for a street 350.

79cc.

Norm

 

7a heads will be 68-70 cc's without milling. FACT
That link is wrong ALSO.

 

Even though I did not cc my 7a's,I got that figure from 442.com's FAQ page. You may very well be right. But you miss the point of what I was trying (not very well) to say. If you take off the 8's and put on an earlier (pre-emissions)head,you will see a pretty fair performance increase. I also used Fed-Mog forged pistons with a .076 dish. It runs well on pump gas.

Brad

 

I have the speedpro flat top pistons with no valve relief on the way im pretty excited about that.

 

So, with a 68 cc chamber, you compression ratio will be over 10 to 1, with the #8s, mid-high 9's. The #8s also have larger exhaust valves and hardened seats, but could use some work on the exhaust side. What cam are you planning? Gears, converter? Pump gas?

 

I already have the new cam installed. Its a edelbrock performer rpm cam. It has a .496 intake and a .520 exhaust lift on it. ill be using 3.73 gears in the rear end. B&M holeshot 2400 converter and yes pump gas 100 octane or 91 octane.