383 build help one piece at a time

cletus said
All the information I have been able to find on these heads on the interwebs says they have a 73.5cc chamber. All the specs I can find on the interwebs show a 1965 383 having a stock compression ration of 9.2:1.

Also, FYI, I used a pair of the same heads from a '65 383 on my 440, when I took them to the machine shop there was hairline crack at one of the exhaust valve seats. The machine shop I deal with usually works on big diesel engines, my cousin had the head sent to their guy to have the crack welded (he assured me they do it all the time on the diesels and that it wouldn't be a problem) before installing the hardened seats. The engine now has probably 3 - 4 hours of run time on it, and so far so good.

Concerning the question of exhaust valve size for your application, I really would like to hear what IQ52 would have to say about it. While I consider myself to have a fair amount of engine knowledge, this dude is like an encyclopedia.

You do what you can afford. If it's me, any big block iron head, for any purpose, gets the hard exhaust seats, 2.14/1.74 or 1.81 valves, throats blended into the bowls and bowl porting.........minimum. I've posted dyno runs with these very heads to show what happens and with other heads changing the valve sizes only to show what effect the sizes make.

However.....sometimes you just do a valve job and reinstall the heads. You don't starve the family because you want your engine to be a bada$$.

Like I've said before, my motto.......There are three secrets to making horsepower. The first two are cylinder heads......and third and most important....is cylinder heads.