camz28arro

iTrader: (12)

yep, same casying just different valves, the lighter ls6 valves shouldn't show any gains on a dyno though.

I'm porting some 241's and will be selling them shortly, looking around $475-500 for them and should be done in a couple days. They should flow better than stock 243s too.

oiLS1

so then, which are better if similar, the 317's 6.0 or the 243's?

and would a set of 806's ported be better?

also will they be better than a set of 241's unported?

im 346 ls1 5.7L stock, just installed longtubes headers and will be using a 220/220 515or525.lift camshaft

and will installing an ls6 intake help or not, since all the info is confusing and im not sure about the numbers yall are mentioning in certain different areas, its true 'i guess every single detail matters and results vary lol

Mike Morris

iTrader: (55)

317s will lower compression-better with boost
Use the 243s for n/a cars and mill them if you don't have a huge cam.

JoshuaGrooms83

iTrader: (2)

ok, so whats the typical HP gain to the wheels with just a 243 head swap from stock LS1 heads and nothing else? So lets say my car, which is making 301RWHP and stock 98 ls1 heads, was to go to 243 heads, what would i be looking at for gains?

mark21742

Stock for stock switching from 241 heads to 243 heads you would be looking at maybe 10-15 HP.... Not worth the time and effort in my opinion unless the heads you are putting are worked over with a valve job, port work and maybe some milled off of them. Swapping out stock heads for worked head can net you 30-50+ HP depending on the rest of your setup

oiLS1

And how much hp gain in stock 98 806s milled ? Ported? Or both? They charge me350$ but the 317s are 150$ unportedstock. Help. I've read that all ls1 heads are almost the same in performance if done by a good porter. And is a 220/220 525.lift camshaft small medium or large? And boosted means what? That it will have nitrious turbo setup or supercharger?

intenseblue

iTrader: (1)

On a budget a 241s are better in ported and milled fashion than factory 243s by probably 20-30whp and you won't lose compression like you will with 317s. Check out Advanced Induction. I believe they port for $600 and have plenty of dyno results, track numbers, and testimonials from board members to back them up. If $600 is too high just get factory 243s.

oiLS1

Thanks a lot folks. Would I be right on saying that it all depends on the porter&price? Since there's a 350$ porter 30minutes away I assume it be better to buy him the 317s for 150$ plus pay extra 350$ for portpolish = 500$ or should I just have my stock 98 806s that are already milled for a port&polish job and pay only 350$ ?would I be missing out on alot if I don't buy those 317s? Help

ramairjohn2000

iTrader: (3)

Old thread sorry but will the 243s. Bolt right up to 5.7 ls1? I was told yes.....

madmike9396

iTrader: (29)

Yes......

ramairjohn2000

iTrader: (3)

gracias one more dumb question What would I need to install new heads? Gaskets bolts, anything else?

ricco texture

I have a set of 243's if interested. I'll sell or maybe a partial swap . I'm in need of a 2000 lm7 for my yukon xl 4wd

G Atsma

You quoted a post made in 2008... and he's LOOONG gone....