I noticed the other day a statement that Quik made when discussing the LS4 intake manifold on a truck.

Now Quik,
How much more stout would this 5.3 be exactly?

Im sure the compression ratio would raise a hair because the compression chambers on the 243 heads are like 54.8 or something like that. Arent the stock chambers on 5.3 heads around 62 or 63cc's? How would 4.8 pistons affect this engine? I thought they are the same pistons but the stroke is shorter on the crank or are they flat top pistons compared to 5.3 dished pistons? If that is the case and 4.8 pistons are flat top or the availability for flat top pistons is there for a 5.3 then would it be safe to say that with the added compression of the heads and pistons that a cam larger than 224 or 226 could run very healthy.

Now with this combo youve got about a billion different directions you could go. If your looking at the flow rates from those heads and intake mix and now your increased RPM range which would people suggest would be the best cam to go with this. Youve got a little more compression to work with now so you can go bigger if you want. One of the harder questions is now how much lift do I want and what time of lobe would be the best for this set up. Then once you get that figured out a stall would be need to be matched up. If I decide to go a route like this then I would look at 4.56 gears to help with some of the low end area but also a cam with a lot of under the curve power can help that too. Keep in mind im riding on a 31" tire and the 4.56 will definitely help there.

Goal for me is mid 12 to low 13 second daily driver. I dont want to go the 6.0 route because if possible I would also like to gun for the 5.3 NA title. Right now im stock so I know I would need full exhaust and LTs to help cam obviously but my main concerns are if I choose the heads and intake first then that can help me choose a cam and a stall follows that obviously depending on the range. Anyways all and any advice or opinions are taken wisely and greatly appreciated.

 

ls6 / 243 castings have a 65cc
5.3 / 862, 706 castings have a 61cc

 

oh okay...well the ls6 heads from summit that are part of the ls1 to ls6 conversion package say 54.something cc chambers

 

I thought you couldn't do that due to the piston pin being in a different place.