Thinking about playing around with the 305 for a while before I swap in my 400 . Wanting to do a heads and cam swap . Wanting to spend in the area of a ccouple hundred bucks on the heads . If I do this I will put a ZZ - 4 cam in it . What do you think ? L-98's ? Vortech ?

 

From what i've heard, the 305 heads with a little modification work really well.

 

305 HO heads 416-castings.

 

I really like the 601 casting better. They seem to clean up a little better, are more plentiful, flow better stock, have the same valve size, and have a smaller chamber for more compression. 53cc vs. 58 cc. The 601s were used on LE9 Vans, possibly trucks, and SOME Monte Carlo SS L69s.

 

Sorry to bump this but I had to ask.. Are you sure they are 53cc? Everywhere I see them sold they are listed as 58cc. I bought mine from Peformance Chevy in AZ with the bigger intake valve already installed along with bigger springs.

They ran good on my 305 with dished pistons. It was almost like they had more compression than what 58cc would bring. So you have me wondering here.

 

I am 1000% sure they are 53 cc. I know of about 15 pair that cc'd that. There was a big debate in a race where one racer accused another of cheating. They tore the engine apart and found the 601 heads were 53 cc. My friend protested and we actually brought about 6 pair of stock 601 castings to be cc'd. All were right at 53 cc. The other guy actually brough 2 pair trying to prove that they were 58 cc, they too cc'd right at 53 cc. He emailed Mortec and they changed their listing on them.

14022601...80-86...267/305......1.72"/1.5" or 1.84"/1.5" valves, 53cc chambers

http://www.mortec.com/castnum.htm

The 601 castings are actually 267 heads that were put onto truck engines starting in 1981 with dished pistons. GM added a 4bbl intake, 350 cam, changed the exhaust up, recurved the distributer, added an knock sensor, and came with 9.2:1 compression. The power output was 175 FWHP @ 4,400 and 265 ft/lbs @ 2,000 atleast for the 1983 G-Series. The LE9 engine ran from 1981-1986.

 

Well that's damn good to hear. I am going to install a thinner gasket when I get my motor back together later this spring. Might get some healthy compression.

It's a reman 305 that's .060 over.
(no I was not stupid enough to do this. Parts America did) Don't know how long it will last with the walls being that thin. lol.