lq4 build. need some advice.

[LeonbergerG]

I'm getting ready to build an lq4. And I've got a few questions on my options for heads. I have 241 heads on my ls1 now. The motor I bought has 317 heads. I'd really like to run one or the other seeing how I'm building this on a budget. Shooting for around 500up at the crank using the stock bottom end good heads and the right cam.. is that plausible?

[STEVE-O]

They are the same head except the 317 have a bigger cc and therefore have lower comp. Cam only 5.7 ls1 cars make 400+ whp so I would say with ported heads and a cam you would be close to your goal. People like using the 317 heads when they go boosted.

[LeonbergerG]

Thinking about sending the 317 heads out for a nice port and polish and milling then I think they will work good in the 6.0

[GSXRAntwon]

I'd put ported 243s on it, they're pretty much the best heads to put on the LQ4, when going N/A

[LeonbergerG]

How cheap can you get a set of 243's though. I already have the 317's budget in mind think I can hit my goal with them.

[GSXRAntwon]

I wouldn't expect much more then 5-15rwhp by bolting on the 243 heads, not from flow but from a compression bump. 317 and 243 heads flow the same which is usually around 260-270 cfm at .600". You will definitely notice the power increase because the over responsiveness and low end power are going to change because of the added compression. LQ4 motors have a valve relief in them so they will be around 10.2:1 with those heads on them. Much better then before either way you look at it. Id stay with the 317's and get them ported....

[Cordell]

They are the same head except the 317 have a bigger cc and therefore have lower comp. Cam only 5.7 ls1 cars make 400+ whp so I would say with ported heads and a cam you would be close to your goal. People like using the 317 heads when they go boosted.

 

This is incorrect, 241 heads are not the same port shape as a 317. 243 and 317 have the same port shape, not to be confused with the fact that the heads are all interchangeable.

 

I wouldn't expect much more then 5-15rwhp by bolting on the 243 heads, not from flow but from a compression bump. 317 and 243 heads flow the same which is usually around 260-270 cfm at .600". You will definitely notice the power increase because the over responsiveness and low end power are going to change because of the added compression. LQ4 motors have a valve relief in them so they will be around 10.2:1 with those heads on them. Much better then before either way you look at it. Id stay with the 317's and get them ported....

 

This is pretty accurate, but since you said crank hp of 500 and these guys seem to be thinking more along the lines of wheel let me put in my $.02. Cam choice, compression, intake, and exhaust are going to have a big impact on final numbers. If you are going to be drag racing and are looking for top end numbers you should be able to hit your goals with a little work to the 317s and an aggressive cam. In my opinion if you're going to do a lot of driving in the car I'd ditch the aggressive cam and settle on less top end, but thats just me. I'd spend the money on a set of rods and pistons which would allow more power down the road and really get compression up with out milling a lot off the heads.

[LeonbergerG]

I have an ls6 intake and mid tube headers. I just need to pick the right cam. Trying to build an 11 second dd.

[Cordell]

I have an ls6 intake and mid tube headers. I just need to pick the right cam. Trying to build an 11 second dd.

 

Well my Z28 will run 11.90 on a 10 inch drag radial the way it sits now, engine is an LQ4 with Scat rods, Mahle pistons, junk 853 heads (ends up at 10.2:1 compression), TSP 233/239 cam, made 390rwhp through a 4L60 and 9" 3.75 gears, went a best of 11.60 at 117mph really leaning on it with a 4200 stall, 11.5" radials and a 1.53 60'.

 

I've been happy with the way the car drives, recently put a tighter 3000 stall in it which is a little small to be doing as well at the drag strip, but I'm not really interested in that anymore. Let me know if you have any specific questions I'd be happy to try an answer them as it sounds like you're going down a similar road.

[Cordell]

I should also state that it was set-up for nitrous and went 10.60 on a 150 shot, which is what I built the motor for in the first place. Once I got up to a 250 shot the car started getting scary, and i could never get a clean pass.

[LeonbergerG]

Yeah it does. I have an m6 12 bolt 3.73's 315/35/17 mt et streets. I think with the right cam and a nice job on the 317 heads in should be able to get there.

[SinisterSS]

if your gonna mill the heads then be very careful with your cam choice piston to valve clearance will be an issue, and speaking from experience upgrade your rear diff if you haven't already

[LeonbergerG]

12 bolt was in the car when purchased. Looking into a cam that's right around .600" lift. Is that going to be an issue?

[gillbot]

12 bolt was in the car when purchased. Looking into a cam that's right around .600" lift. Is that going to be an issue?

 

depends on the duration, after you get your heads right, call and ask about cam choices.

[SinisterSS]

12 bolt was in the car when purchased. Looking into a cam that's right around .600" lift. Is that going to be an issue?

 

the cam in my SS is a .608/.612 duration @ 0.50 .242/.248, if your gonna run a cam that size I wouldn't mill the heads unless your gonna change out the pistons also you'll need a 4.30 or higher gear ratio, I too have an M6, I'm running 4:56 gears, so you know I've gone through 3 transmissions, 1 rear diff, 4 sets of ring and pinion gears, 1 engine block, and countless other crap.

 

so make your cam choice based on how often your gonna drive this car, remember gas isn't going down anytime soon, a cam that size in a DD is gonna put a strain on your wallet over time along with broken parts when your out beating on it for fun.

[LeonbergerG]

depends on the duration, after you get your heads right, call and ask about cam choices.

 

That was my plan. But going to try and pick up a cam either used or a cheap New one.

[LeonbergerG]

http://ls1tech.com/forums/parts-classifieds/1420187-complete-lsx-cam-kit-new.html

 

This is the cam I was trying to buy 694/609 lift 234 242 duration

[LeonbergerG]

http://ls1tech.com/forums/parts-classifieds/1420187-complete-lsx-cam-kit-new.html

 

This is the cam I was trying to buy 604/609 lift 237 242 duation

Edited May 26, 2012 by LeonbergerG
smart phones right

[Cordell]

With milled heads you'd want to check it, but I'd think with the dished LQ4 pistons you're likely to be fine.

[AWW$HEEET]

Surprised no one has mentioned l92 heads. Car craft did a similar build up with numbers at or close to what you are looking for.

[Cordell]

Surprised no one has mentioned l92 heads. Car craft did a similar build up with numbers at or close to what you are looking for.

 

Well seeing as how he wants to stay on a budget he already has this stuff. While they are good heads that will work on the LQ4 he would also have to get an intake manifold, injectors, fuel rails, different rocker arms, throttle body, and a few other adaptors in order to run them. It didn't seem to fit what he was asking.

[LeonbergerG]

Well seeing as how he wants to stay on a budget he already has this stuff. While they are good heads that will work on the LQ4 he would also have to get an intake manifold, injectors, fuel rails, different rocker arms, throttle body, and a few other adaptors in order to run them. It didn't seem to fit what he was asking.

 

Bingo!

The guy im getting the motor from has a set of l92's but we discussed that it would be more then I want to spend on the build. And I can still get good numbers out of the 317''s

[LeonbergerG]

Ok.... thinking hard now about going boosted. Anyone have a boosted lsx? Want to keep air and power steering.

[gillbot]

Nobody around has a boosted LSx, they are all stock. ;-)

[LeonbergerG]

Well maybe I could be the first then?... rrrrright..think I'm just gonna go N/A for now. Maybe boosted in the winter??