hellhound405

Does anyone have an idea of how much HP I will gain from putting on a set of 806 heads with ls6 lifters, ls6 pushrods, ported and polished, bigger valves (not sure what size yet) and stock valve springs? Just looking for a round about number..

RPM WS6

iTrader: (3)

All LS1 heads have equal potential as ported pieces, doesn't matter of they are 806, 853 or 241. Beyond that, you haven't really given enough additional info for a reasonable estimate.

sillysspeed

iTrader: (21)

15-25hp depending on the rest of your combo. Invest a couple $$'s in better valve springs. You will be giving up some higher rpm power if you don't

usnfenix

iTrader: (11)

honestly for the cost of the work and pain of the install you might as well spend an extra 350-400 and get some 243's for the better flow numbers and then do all that and make more power with a better flowing head. Correct me if im wrong but wasn't the 806 the first LS head? the design has seen multiple improvements from 806-241-243

RPM WS6

iTrader: (3)

806 was the first LS1 F-body head (I don't remember if '97 C5 used this same casting or not), but the 241 is not an improvement other than the casting finish - and that is obviously negated once both heads are ported. No point in swapping between 806/853/241 just for porting, unless it's to make core exchanges easier and/or to switch valve cover arrangement for applications where this might be beneficial.

243, of course, would be an upgrade.

sillysspeed

iTrader: (21)

I agree with going to 243 heads if the budget will allow. Especially if you can get your hands on a set of coils and valve covers for cheap since you will need to change them. Depending on your goal you can make good power and quick et's. I still run 806 heads and have been 10's on motor with ls1.