ls3 top end for 408 lq4
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Joined: Jan 2013
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From: Bear, De
ls3 top end for 408 lq4 Started this in the gen 3 section with no avail, I got a truck engine a while ago and got started on it. This is going in my 72 Nova setup for roadcourse and autocross but more towards roadcourse and street. The lq4 was an 04, I got a forged rotating assembly from Texas Speed, lunati crank, lunati rods with ARP bolts, weiseco -3cc pistons and ARP main and head studs. The bottom end has been machined and assembled by the shop doing the work and I'm looking to try and figure out my top end. I'm still looking at l92/ls3 heads, either stock or prc, still open to suggestions though and a victor Jr intake with a 4150 throttle body retaining the fuel rails. The motor should handle boost fine if I decide to add it one day but that's far away so I could use some more compression now. I will also need a cam to match, keeping in mind the car will see mostly street but also road course and auto crossing. Any thoughts or suggestions are greatly appreciated especially since I'm deploying and would like to have the motor complete for when I come home. I will be backing the motor with a t56, I'm shooting for over 500 at the wheels, and I've already setup my current exhaust for the new motor, full 3 inch mandrel with x-pipe and SLP loudmouth 2 mufflers and tailpipes.
http://www.advancedinduction.com/LSX...cGMLS2Head.php
http://www.advancedinduction.com/LSX...cGM823Head.php
These are 2 somewhat budget friendly options.Phil at ai or Martin at tick performance can also give you some good cam spec options.
If you want to to lay down the big money.
http://www.allproheads.com/Images%2013/AllProCat13W.pdf
http://www.mastmotorsports.com/2010/...0-%20Assembled
http://www.advancedinduction.com/LSX...cGM823Head.php
These are 2 somewhat budget friendly options.Phil at ai or Martin at tick performance can also give you some good cam spec options.
If you want to to lay down the big money.
http://www.allproheads.com/Images%2013/AllProCat13W.pdf
http://www.mastmotorsports.com/2010/...0-%20Assembled
You should be able to make it to 500 rwhp without ported l92/ls3 heads especially since you have quite a bit more cubes. Ive got a 370 lq with stock crank that made 460 thru a TH400 and 9". Should put a stick car right around 500 rwhp. Cam is pretty large though 251/265 .650 .650 115+4 shifting around 7000
With PRC LS3 heads, 102/102 Fast, TSP LTs, 4"exh, Elec WP, cust cam, pulleys, AC...with Lq9 408, etc, etc..all the good stuff. I do have stock rockers though, but they were new. Got 517/497 through 6spd. Just a street car that saw about 200 miles last year.
Thread Starter
Teching In
Joined: Jan 2013
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From: Bear, De
Thanks for the replies guys, I'm really set on the single plane intake as it still gives the old appearance and I'm really set on keeping a 14" air cleaner since I don't want to have a tubular intake pipe and cone filter.
Thread Starter
Teching In
Joined: Jan 2013
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From: Bear, De
I've been looking more at the GM cnc ls3 heads, they are pretty cheap since I don't have castings to start with and with a good spring upgrade should handle about anything I throw at them for around 1500. I would probably be looking at the prc .650 double spring kit with titanium retainers, and keep the gm valves since they come with the hollow intake valves.
My next question is since they come with 68cc combustion chambers what do you think my compression ratio would be? I have -3cc pistons, I would probably go with a mls .040 head gasket that has a bore of 4.035, 4.030 bore, 4" stroke, the calculator I used showed around 11:1, does that sound right at all or am I going to end up with less or more?
My next question is since they come with 68cc combustion chambers what do you think my compression ratio would be? I have -3cc pistons, I would probably go with a mls .040 head gasket that has a bore of 4.035, 4.030 bore, 4" stroke, the calculator I used showed around 11:1, does that sound right at all or am I going to end up with less or more?
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