Here's what I have. I have a 1979 350, 600 cfm carb, comp 270h-10, new lifters, new springs, new double roller timing chain, holley street dominator 300-38 intake, and a new holley mechanical fuel pump. Should I keep my 350 heads or switch to my 305 heads? About how much would this combo be worth as far as h.p. ?

 

What are the 350 heads, 882 castings? If so, probably go with the 305 heads, depending upon what they really are. So, what heads do you have?

There have been several posts recently about porting. Check them out.

If your heads are 416, 601, or 081, ported w/1.94" intake valves, with headers and decent exhaust you can expect a good 300+ HP.

 

whatever was stock on a 79 chevy van. Wasn't the original motor that was in it, but they said it came out of another 79 chevy van

 

Truck heads - not good for performance.

Go through your 305 heads (assuming they are the '86 LG4 or LB9 that came with the car).

 

what's the vin code for those motors? I'm not sure I'm thinking lg4 but I'm not sure

 

LG4 = H (had a q-jet carb stock)
LB9 = F (had TPI fuel injection stock)

Available on the thirdgen.org homepage Tech Data link.

 

it's an H

 

The lg4 heads have a lot of potential if they are ported. I say do a DIY port job on the 305 heads and put them on the motor. Chances are your 79 van motor has very low compression and terrible heads on it. Just about anything late 70's probably did.

 

any suggestions on porting (how, how much, where)? Do Ineed new head bolts?

 

I won't be able to use my 305 heads. That would put my compression to 10.96