you will see a much bigger gain with the LS6 heads then the LS6 intake.
the ports are larger, the valves are larger, and the flow will be more then what you have now.
it will cost you less to rebuild a set of LS6 heads then to have your 5.3 heads,
ported. polished, milled, and cut for larger valves.

 

243 castings have the same size exhaust valve as the 5.3 and the same intake valve as a regular 317, which only main difference is the CC of the head besides that a 243 casting and 317 are same but also dont forget shrouding of the valves with the smaller bore

 

so what do you recommend quik?? should i try to find some LS6 heads on ebay, save up for some stage 2 patriots or take my current heads to be ported/polished? or just say heads later and then do the intake... with the custom grind im looking at im quite worried i will be robbing mself of alot of potential power due to the stock manifold

 

brian at TEA said just the opposite the other day. he recommended going to the FAST 90 with the LS-2 TB (or the LS6 intake for us poor folk) and just basically doing a home cleanup on a set of heads, with a "quality" valve job. he reiterated "quality" on the valve job, and that good flow comes from a good valve job.

he was also saying that without definitive proof, i.e. flowing a set of heads with a 3.78" bore plate in place you are pretty much shooting in the dark with an assumed increase in performance using the 2" intake valve on our small bores. flow numbers using a 3.90" bore plate and trying to use them in a 3.78" motor is not an apples to apples comparison.

 

oh forgot...

210/218, truck intake, ~5900