Najania

Im in the middle of an ls swap, with the engine still sitting in the stand for easy access.

I have the 98' 806 heads on it right now, engine completely stock, looking to do some upgrades before i swap in it.

What heads would you use for the following combo:

Plans are Longtubes, CAI, GM Hotcam kit(or equivalent with 550 lift) LS6 intake, ported TB, and one set of heads im not decided on yet.
99% streetdriving 1% track, with a slightly bigger stall and some 3.42's in the rear. Driveablity is important to me. And i'd like to keep the engine "all gm"

1)I already have nice clean 799's off a L33 with 80k mile.
2)And some lightly ported 241's that i would mill before using due to some idiot scuffing them slightly on the underside.
3) Stock perimeter bolt 806 heads that i port myself.

I have built many engines, and made several LS swaps, but never ported heads.

Option 3 would be cheapest as i could reuse valvecovers, coils and coil brackets, and fuel rail.

Option 1 and 2 would cost me more money as i would need new coil brackets, or perhaps just adapt the existing ones. Im not 100 percent sure i can reuse the inlet/outlet fuel rail if i change over to the centerbolt heads either that usually is with a returnless fuel rail. I do have the valvecovers though.

So. What would you do?
-Just port the 806's where i know everything will fit.
-or go with the slightly ported 241's and buy some coil brackets and possibly coils and rail.
or make room for further gains in the future and go with the 799 heads that need the same parts as the 241's to be used.'

I wont be doing further upgrades to it than H/C/I and the usual boltons. No supercharger, turbocharger or n2o in the future. And i wont ever need 500rwhp or more in this LS swap.

RPM WS6

iTrader: (3)

As for the 241 vs. 806 portion, there is absolutely no advantage to a 241 over an 806 once both are ported. At that point, any advantage lies in the port work and not in the casting itself. So the only question between these two is, do you want to do the work on the 806s, or source the parts to make the slightly ported 241s fit? There is really no other difference between them as all LS1 heads (806/853/241) have exactly the same power potential. In this case, it sounds like the work already done on the 241s isn't much, and they need some cleaning up on the bottom, so perhaps you'd be better off just doing the 806s proper from the beginning and then reusing all the perimeter bolt hardware. That's what I would do in this case, if I was going to stick with an original LS1-specific casting.

Najania

Thanks.

You wouldnt consider doing no porting at all and just slap on those 799 heads instead?

RPM WS6

iTrader: (3)

If you're already removing the heads, I would not personally want to put unported 799s back on (too much work for not enough gain.) A well worked 806/853/241 head should show better results than a completely stock 799/243 head.

If you're going to source the parts to make a center bolt head fit, then I'd just port the 799s. Otherwise I'd rather port the 806s and not bother with finding valve cover parts.

Would you not be willing to port the 799s? Seems like that would be the best option if you're already willing to port the 806s, and also willing to source the parts to make a center bolt head work.

Najania

Well. I havent ported any heads so making the 799 my first project is a bit dangerous i feel. I':"d rather practice on the 806 heads, or finish up the 241's, before i try my luck with the 799's.

I found some interesting info though, on ls6 intakes with ls1 vs ls6 style heads. Being that im going with a relatively mild cam(hotcam) im leaning more and more into using 806 heads.
1 thing that makes me want to use the semi finished 241's though is i only need to grind a few spots in those to make it work and that they have the triangle casting marks on them which i have read always duno 5-7hp better than other castings somehow..

Anyways, thanks for the tips so far. I appreciate the feedback

Najania

Najania

If i add up the increased cfm numbers and make an average of the mumbers from the ported ls1 heads with ls6 intake, versus the stock 243 heads with ls6 intake, the ls1 heads with ls6 intake flows in general 10.3 cfm more in average across the board.

Now this would require me to be real good at porting to achieve those Ls1 heads numbers. But it's still an interesting comparison.

Compared with ported ls6 heads, the ls1 castings still are superior up until 400 lift, and not much behind higher up in the lift range. Meaning, to fully utilize ported ls6 heads is need a better intake.

RPM WS6

iTrader: (3)

I didn't fully understand that you would be porting them personally and without experience; by "you" I thought you meant either a local shop of your choosing (vs. core exchange with a mail order shop), or that you were comfortable with doing the job yourself.

If the porting work is of equal quality, there will be no difference in performance between a 241 and an 806 or 853 head. No LS1 casting is inherently superior or inferior to any other once ported. 241s have a slightly better casting finish from the factory, but that's negated once either had been ported.