does anybody know what size chamber these heads have.
3986388....68-76...307/350
i want to put my ported 305 58 cc cylinder heads on this 350 i just got. Also it would be helpful if anybody could tell me how much the ocmpression will raise by switching heads...the engine has about 8.5:1 compression...what wopuld it be if i switched form 76 cc to 58 and from 64 cc to 58

 

Specs on those heads should be listed here.

 

i looked..it doesnt say the chamber size

 

www.mortec.com

 

dude guys mortec does not list the chamber size on these. All they say is what i included in my first post

 

I believe you'll find that those are either 72cc or 75cc.

Doesn't much matter though; they are the dung. They are the sort of thing that I threw away dozens and dozens of sets of, all through the 70s, as people would come up with them saying "I got these cheap, what can I do with them", and my answer would always be the same, "throw them away and get decent cores". You have no idea how much I laughed at people who thought they could re-invent the laws of physics by being "different", and spent gigabucks on big cams, carbs, Torker 2 intakes, Doug Thorley headers, etc. etc. etc. etc. to go around them; and the more they spent, the slower their car got.

It's beyond pointless to try to look up "specs" for some old motor, and then guess what the CR will be after a head swap. That doesn't work. A better way to go about it would be to determine what pistons are in it, first; don't worry about what the CR is now, at all; and concentrate on identifying or measuring what you've got, to determine what the best course of action would be.

 

Those heads use tiny 1.72/1.50 valves. Any head that uses these small valves has no real performance potential. Chamber size means nothing if the intake runners are so restricted that they won't flow enough air to get any performance.

 

Click on this link

 

ok ok...dont worry i wasnt planning on messing with these heads at all. Is there any way to check what size the dish is on pistons once i tear the top end off? I dont have the heads off yet but it is a virgin motor and the insides have never been touched. I just wanna know if ill be able to run 93 with the 416 heads off the 305. the chambers are still 58cc because i didnt do any bowl work, just the ports. Im thinking about tapping the heads for screw in studs to allow me to run a bigger cam with my new converter but i have never done it before. Is it hard?