Hey all, it’s been many moons since my last post, at least since my TA was sold a while back.

I have a question about heads but let me elaborate on my situation first. I am building a SBC for a marine application and this is all new to me. Apparently low compression and quench are very important because of the different loading on the engine comp aired to an automobile (an online article in CHP mag stated optimal comp to be 8.2 to 1 for a marine engine). So with a set of flat tops, 75cc heads, and a quench area set at .035-.045 I will be able to ward off detonation.

I have a set of SBC heads that are casting numbers ending in 775. They are for 1963-67 Chevy trucks. I need these heads because I have to run an open chamber with a flat top piston in order to maximize quench. I can’t run much more than 9 to 1 either.

Did a search hear in this forum for 775 heads but got only a few non related threads. Will these 775 heads flow better than a set of swirl port heads? (no accessory bolt holes is not a concern at the moment)

 

Looks like they came on 283s and have tiny little valves. You might be better off with the swirl ports lol.

 

Yeah I am afraid of that too.

The guy that I take my machine work to thinks he may be able to go to the larger valve sizes and open up the bowl area slightly as long as they are a heavy casting. He won't do it if he thinks there's any chance of it not working.

We'll see. I have nothing into them at this point.