How much to you gain putting 243 heads on a lq4
#21
Dang I never knew the 317s had a bigger chamber than the 243s. I had read they were basically the same. I've got an LQ4 but it's the early style with iron heads so I've been trying to decide what heads I want. Was trying to find a cheap set of 317s since they are cheaper than 243s.
I think I'm going to go with L92s and an LS3 intake. LS3 intakes are as cheap as LS6s and the heads will only be a little more, but that combo will make more power than 243s with an LS6 intake.
I think I'm going to go with L92s and an LS3 intake. LS3 intakes are as cheap as LS6s and the heads will only be a little more, but that combo will make more power than 243s with an LS6 intake.
The L92's will make more power than the 243's...short answer, yes.
But ONLY at high RPMS. The 243's offer the LQ4 more power at low/mid range.
You will not be able to bump up your compression as you will with the 243's.
The following users liked this post:
Homer_Simpson (12-07-2021)
#22
TECH Enthusiast
iTrader: (9)
These are LS2 heads (799 or 243 castings) but do not come with the sodium filled valves.
Check around with your local GMPP dealer, they gave them to me for the same price.
#23
TECH Regular
iTrader: (12)
http://sdparts.com/details/gm-perfor...parts/12576063
These are LS2 heads (799 or 243 castings) but do not come with the sodium filled valves.
Check around with your local GMPP dealer, they gave them to me for the same price.
These are LS2 heads (799 or 243 castings) but do not come with the sodium filled valves.
Check around with your local GMPP dealer, they gave them to me for the same price.
#25
I'd like to get some 243s and mill them to 10.5:1 compression on my LQ4.
#26
TECH Resident
iTrader: (14)
PTV is affected by head gasket thickness, deck height in relation to how much (if any) the piston protrudes from the block, valve size, chamber size (milling) and camshaft duration and ICL, not max lift. Max lift occurs closer to BDC, and isn't a factor.
Last edited by Squirts11; 11-04-2011 at 03:24 PM.
#29
By the way, most LQ4 pistons that I have seen do not have that cross-shape to the dish. My LQ4 is from a 2005, and the center dish has no cross. (or valve relief indentation)
#31
I can modify pistons or buy them so that is not so much a factor. What i am really curious about is how much meat can i lop off the heads before they become too fragile to handle the added compression. I want to build the LQ4 motor I have to it's max potential ... and like everyone else would like to do it the most economical way possible. I want the highest compression possible to run on race gas. Keep in mind i am running a Carb. My thinking here is use the best flowing head with the smallest chamber and cut them to the limit. Do whatever i have to to run my Texas Speed cam with .603 lift. TO get my name in the record books and keep it there i am thinking i will need close to 500hp; on gas;with no power adders or computers. Is this possible?
Fred
Fred
#32
After reading the whole thread I was wondering I have lq4 or lq9. Not sure witch one because I have not taking the 317 off yet. But I have 243's, ls6 cam,fast 90mm intake, 90mm intake, fast fuel rails, and ls6 injectors. How much hp and torque will that make an will a stock 4l60e hold it.
#33
I think that would be a great move as the 243s will pick you up a decent bump in compression which will help quite a bit with driving this motor on the street. The heads flow right about the same but the compression bump is more then enough of a reason to do the swap in my opinion.
#34
11 Second Club
iTrader: (88)
Came across this thread doing some reading...some bad info in here..
I have yet to see a factory LQ4 with "valve reliefs" in the pistons...all the ones I have seen are dished. That pic above the piston on the right is a 5.3l Piston...you can even see it's smaller in the pic compared to the one on the left.
I have yet to see a factory LQ4 with "valve reliefs" in the pistons...all the ones I have seen are dished. That pic above the piston on the right is a 5.3l Piston...you can even see it's smaller in the pic compared to the one on the left.
#35
TECH Senior Member
iTrader: (26)
some lq4's did indeed come with valve reliefs for one valve.
https://ls1tech.com/forums/generatio...t-pistons.html
https://ls1tech.com/forums/generatio...t-pistons.html