Another 370 LQ4 Question Thread*
Another 370 LQ4 Question Thread* Hi Guys I know these threads get annoying but tommorow I am going to a few local junk yards and look for a lq4 short block I know what I want to do with the engine but I dont know what I would use to get the result I want.
I know I want the Lq4, get it bored .030 over to make a 370 now the question is what type of piston to run flat-top or dome and if I will need valve reliefs. I want to run 11-1 compression so I can run 93 octane. My plan was to run L92 heads but now I am second guessing myself because I dont want to run into PTV issues. I am going to run a custom cam but will be close to the torquer v2 specs (Torquer v2 specs: 232/234 .595/.598 112 ). So I dont know if I should go with a set of 243's. I am going to run a Victor Jr intake with a 800cfm carb. I know you guys can point me in the right direction Thanks alot!
I know I want the Lq4, get it bored .030 over to make a 370 now the question is what type of piston to run flat-top or dome and if I will need valve reliefs. I want to run 11-1 compression so I can run 93 octane. My plan was to run L92 heads but now I am second guessing myself because I dont want to run into PTV issues. I am going to run a custom cam but will be close to the torquer v2 specs (Torquer v2 specs: 232/234 .595/.598 112 ). So I dont know if I should go with a set of 243's. I am going to run a Victor Jr intake with a 800cfm carb. I know you guys can point me in the right direction Thanks alot!
You can run the LQ4 with L92 heads and flycut the pistons. Thats what Im gonna be doing here very shortly. The problem is gonna arise trying to get 11 to 1 CR. With everything all stock with the 70cc chambers you would be around 9.64 according to my calculations. You would have to mill down to 58cc to get 11 to 1......by the time you flycut the piston you probably wouldnt have much piston left.
11-1 or 10.5-1 Somewhere in that range I want a high compression motor I can run on available 93 Octane. Yes that's what I am worried about so whats a good head to go with 243's ? Because of smaller valves and the bump in comp ?
Set on 93 octane, Well pretty much in my town you can throw a rock and hit 3 gas stations that sell 93 octane but have to drive an hour away to get any type of fuel over 93 octane. Ok sounds good I will look into finding a set.
I found a set off texas speed (http://www.texas-speed.com/p-4-prc-s...ted-heads.aspx) - How good of a set of heads are those ?
I found a set off texas speed (http://www.texas-speed.com/p-4-prc-s...ted-heads.aspx) - How good of a set of heads are those ?
Last edited by 973800CamaroRS; Nov 18, 2011 at 10:39 PM.
Why do you need such high compression? You can make power with lower CR. Im gona be pushin it to get 10 to 1. But i guarantee its gona peel the **** out. Do a LQ4/L92 combo search on here an see for yourself. Granted the 243's will be cheaper and you prolly want have to flycut. Your call.
FormerVendor
Joined: Jun 2011
Posts: 890
Likes: 3
Set on 93 octane, Well pretty much in my town you can throw a rock and hit 3 gas stations that sell 93 octane but have to drive an hour away to get any type of fuel over 93 octane. Ok sounds good I will look into finding a set.
I found a set off texas speed (http://www.texas-speed.com/p-4-prc-s...ted-heads.aspx) - How good of a set of heads are those ?
I found a set off texas speed (http://www.texas-speed.com/p-4-prc-s...ted-heads.aspx) - How good of a set of heads are those ?
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If he is going 30 over, he is probably going with an after market piston, no need to fly cut. If you get a domed piston it will have valve reliefs for the valves And still be able to hit 11 to 1
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I'm in a similar boat. Im going to have an LQ9 370 shortblock built and its going to have 11.7:1 compression. If you want to go with a stock casting I would go with LS3/L92 heads, but you have to get offset intake rockers and a rectangular port intake.
Well I am just like anyone and have a budget and no offence I just cant see me spending over $1600 on heads dont get me wrong I would love to have a set of AFR's. Yes I am going to go with an aftermarket piston probably a forged diamond piston with 2cc valve reliefs and I am now thinking ported 317's with 65cc chamber.Cause If thats what come on the engine I could have them ported and it would be a cheap method.
(http://www.texas-speed.com/p-1173-pr...ted-heads.aspx).
With that Combo I am looking at about a 10.9 comp ratio. The reason I am going high compression is because I dont want to leave any power on the table, not to sound greedy
(http://www.texas-speed.com/p-1173-pr...ted-heads.aspx).
With that Combo I am looking at about a 10.9 comp ratio. The reason I am going high compression is because I dont want to leave any power on the table, not to sound greedy
I have the flat-top Diamond pistons (with the 2.2 v/r) in my 370, running 12:1 comp using PRC 5.3 stage 2.5 heads and I am very happy. I haven't had any issues running 93 yet, granted it runs much better on 93+.
I strongly considered going L92 topend as well, and probably eventually will, but I already had everything for a head/cam swap for my old LS1 (that is another story..haha)
I strongly considered going L92 topend as well, and probably eventually will, but I already had everything for a head/cam swap for my old LS1 (that is another story..haha)
I know the l92/ls3 heads are great at flowing and are cheap but what I am worried about PTV clearance even with pistons with valve reliefs.
I looked at two junk yards today and only found two 5.3s and an iron 5.7 not a single Lq4/Lq9. Finding these engines may be harder to find than I thought. I'm Just looking for the block and crank or a shortblock.
I looked at two junk yards today and only found two 5.3s and an iron 5.7 not a single Lq4/Lq9. Finding these engines may be harder to find than I thought. I'm Just looking for the block and crank or a shortblock.
I know the l92/ls3 heads are great at flowing and are cheap but what I am worried about PTV clearance even with pistons with valve reliefs.
I looked at two junk yards today and only found two 5.3s and an iron 5.7 not a single Lq4/Lq9. Finding these engines may be harder to find than I thought. I'm Just looking for the block and crank or a shortblock.
I looked at two junk yards today and only found two 5.3s and an iron 5.7 not a single Lq4/Lq9. Finding these engines may be harder to find than I thought. I'm Just looking for the block and crank or a shortblock.
On The Tree
Joined: Oct 2011
Posts: 102
Likes: 0
From: Dirty South
Ok after you guys preaching the L92's I think I am going to go with them with a 65cc chambers to get my compression to abut 10.9-11 to 1. I'm still worried about PTV clearance even with the pistons with valve cuts in. I'm not running a huge cam I just want to make sure I wont have issues.
The Pistons (http://www.hawksthirdgenparts.com/di...ipflattop.aspx )
The Pistons (http://www.hawksthirdgenparts.com/di...ipflattop.aspx )
Now that you have picked heads, time to pick a cam. The torquer you have picked out ain't going to shine with k92 heads. With the l92 heads you can run a smaller cam and make bigger power. Best bet would be a custom cam.
Yes I know Custom Cam all the way. But I still want to run a cam similar to the torquer for operating range (2000-6500). This engine is going to be carbed with a Victor JR. I'm shooting for 450rwhp through a t56 you guys think it can be done ?