Question about porting my own heads
Hello. I have a set of heads that I am very confident I can port myself.
The heads are casting # 333882 they are sbc heads that have been cleaned magged, etc. I am not sure what they came off of, but I am going to put them on a 4-bolt main 350 block from the '77 -'79 era.
The motor is being set up for street use with the rpm range from 0 to no more than about 5500. I was initially going to go with a 383, but decided against it.
I have read plenty up on do it yourself head porting and I know I can do this if I am careful. The specs on these particular heads are as follows;
Intake flows about 137 cfm
Exhaust flows about 95cfm
The two obvious things that come out at you are the exhaust number and the large chambers. I plan on alleviating the large chamber size by running a domed 11 to 1 piston to get the compression to about 10:1. As far as cleaning up the runners. I am going to use a few intake manifold bolts to postition an hold the intake manifold gasket in place on the head--using the gasket as a template--to scribe out excess material on the intake runners. Basically I am matching the intake runners to the gasket. I am not going to get to carried away on the intake side, however on the exhuast side I am going to spend a little more time to bump up that exhaust number of 95cfm. I plan on cleaning up the bowl area staying a 1/2 inch or so away from the seat area. The idea in using these particular heads with 1.94 intakes, 1.5 exhaust, and not heads with say 2.02 intakes and 1.6 exhaust is so the velocity of the mixture going into the chamber will be a little better. At higher rpm--above 5500--I know the 2.02's would probably be better.
Can anyone provide any additional insight, potential problems I might encounter, or there own success on doing the same job?
Yeah, I know I could have bought aftermarket heads that flow better right out of the box, however; I basically got these heads for nothing, so there you have it.