Would ls1heads shaved for more compression, be better flow-wise than the stock 4.8l heads?

 

They would flow better, but you would still have less compression. I have a set of P&P 4.8/5.3 heads and they made a big difference on my 5.3. But I bent a couple of valves when I blew my motor, so right now they are being used as paper weights till I get around to getting some new valves. Then Ill probably sell em

 

4.8T put a set of stock LS1 heads on his 04' 4.8. The compression ended up around 9.1:1, but it had noticable power increase through the entire rpm range and was pulling 3 more lbs of air. I'd say with the stock LS1 heads and tuning a little more he easily gained 20hp up high. Mill them .050 which will cost $100 and they will be just above stock compression. Dont forget new pushrods if you mill them more than .020.

 

make sure to get 241 casting LS1 heads as they flow the best.

 

they do not flow any different than the 853 castings

 

That is correct. Just different foundry's.

Richard

 

Richard,

Thank you for that, there are some people that will argue until they are blue in the face about that.

I have a question on your heads though, do you see much of a pickup going from the 2.00" valve compared to the 2.02 on the ls1 heads?


Ryan

 

4.8/5.3 heads have 1.96 intake valves. LS1 heads have 2.00 valves.

 

How would a pair of stock LS6 heads work on a 4.8? I have a set lying around in my garage, including an LS6 intake and Lunati Cam 224/227 112 .589 lift.

 

They flow better than the LS1 heads on the exhaust side due to the "D" shaped port. They will also not drop as much compression due to the chamber size ( 65cc vs 68cc ).
Using the intake will cost you a ton of low end power over the truck models, plus you would need to install the LS1/LS6 belt drive system ( the car intakes are lower and the TB interferes with the water pump outlet ). The truck intake shows as good or better at all RPM's below 5000.
The cam would be a nice combo with the heads as long as you get the CR up a tad.