hcb1700

iTrader: (9)

I just want to know if it would be worth swapping the stock LM7('00) heads for some LS1('01) heads since they have bigger valves? My brother did a heads and cam swap on his Z28 and these parts are just laying there. Would they work/fit without any problems? Don't the LS1 heads have smaller combustion chambers, therefore giving a slightly higher compression ratio? I'm looking into swapping this engine into my '78 Z28 and need to know this before I drop it in.

chevyboy91188

iTrader: (15)

Ls1 has bigger chambers, don't know where you heard they are smaller? Think about this, ls1 is a bigger engine and compression ratio is what? Like 10.5 to 1, the 5.3 is smaller and its cr is 9.5 to 1 those are pretty close especially considering the ls1 has flat tops and the 5.3 dished pistons. The heads almost flow the same too. A common upgrade on ls1 is getting 5.3 ported and have bigger valves put in them. Really no one wants ls1 heads unless they have the l33 like me which has 9.9 cr due to flat tops in this model, and I would only need them to lower my cr so I could use forced induction.

deuce4935

iTrader: (2)

What I did was took the ls1 valves and installed them on the 5.3 heads, had them ported and polished along with a spring upgrade.

hcb1700

iTrader: (9)

What cam are you running?

deuce4935

iTrader: (2)

A Comp custom grind with low .600" lift.