I'm new to this forum and i swaped an LQ4 into a 72 GMC truck with a 700r4 behind it. I had it dyno tuned and the numbers were a bit disapointing 323rwhp and 342tq. it runs a 13.6 @99 and what i want is to run about a 12.9 or so and put down 400hp. It has the hot cam 525lift 218 in and 228 ex with 112lsa, long tube headers ls6 valve springs and truck intake manifold. power peaked at 5K and stayed flat till 6k. I am thinking about going with a fast truck intake along with a 90mm throttle body dbw, and changing the cam i read bad things about the hot cam thinking of a tr 224 with 112 lsa, i like the lope and don't need to pass emisions even in cali due to the year any suggestions i've built a few gen 1 small blocks but am new to ls engines thanks also gear ratio is 3.5 ford 9in rear, numbers were with converter locked by switch, 275/60 r15 tires steel rims thanks

 

A different cam, fast intake and some ported heads will make 400 after a retune

 

X 2 that cam, a good set of heads and a tbss intake/injector swap will put u over 400 and im sure ud reach ur goal

 

tr224 and PRC ported stage 2.5 5.3 heads
no way i would spend all that money on a fast intake setup...heads are the same price and will out perform an intake manifold
400hp look up truckshop he has a dyno of his 6.0 setup like this

 

considering the cost of the FAST 102 setup, i agree. send your heads out to TEA or AI and let them run their CNC program. it will cost just a little more but give bigger gains. have them milled to bump your compression and have a professional spec your cam to match the heads. i had no problem getting my smaller cubed LS1 over 400 HP using the truck manifold and some low budget heads.

 

Mine makes 403rwhp 390tq through a 4wd transmission.

LQ9
MS3 cam
Lightly ported/milled 317's
TBSS intake
Marine 8.1's
90mm TB
Shorty headers
3'' exhaust no cats

 

i made 390rwhp LQ4 AI ported 243s AI custom grind cam 226/230 600/600 111+3 4.10s 3600 stall i should be well in the 4xx range since i put the LSXRT on

 

just send it to CAGRacing, he'll get you 400 at the crank and a 10 second truck

 

I was reading through that thread a minute ago and all I've got to say is WOW!!

 

thanks for the replies i was thinking about doing heads but when i looked at the graph and saw the flat line i was thinking maybee it's the intake holding it back i saw carcrafts lq4 build with the same cam and it made 480 at the crank i know things might be a little inflated for advertising but i didn't think that much and for the compression i didn't think a half a point was quite that big a deal and also i can only get 91 octane fuel another question is the 90 mm throttle body necesary to make that power in wich case i would have to swap intakes anyway but might go with a cheaper truck intake with 4 bolt pattern, and txsilverado did you have the 90mm throttle body on your ls1 with the truck intake