K well this is what is goin on, I picked up a LQ4 from a 99 cehvy truck. mileage was bout 70,xxx pick it up for 600$? good idk sounded like it though. K now i plan on swaping this motor into my 90 firebird formula, with a t56 from a ls1 based firebird/camaro. Now i have read somewhere that the LQ4, can handle up to 700hp with out any mods to the bottum end ( true?/False? ). Now i have a come up with a list for this engine, Heads, cam, intake, ext. First let me ask this, On the lq4 the year i got 99 i have to swap the crank (LS1) right? to make the t56 bolt up to the flywheel? correct if not let me no what i have to do.

Now for the parts list,
Heads-( Patriot LS6 series head combo )- chamber volume is 59cc, intake 235cc, exhaust 83cc. ( to much? that will raise my compression? but how much, dangerous?) cam specs-226/226 585 lift both in/ex 112 lobe seperation. ( if this combo wont work i was thinking maybe ported out ls6 heads? suggestions.
Intake-Edelbrock PRO-Flo XT with the fuel rails,
Throttle-body-fast 92mm
Injectors-(i was thinking maybe 32-36lb)
Headers-Hawks conversion long tubes

Now i no that the t56 stock prolly wont be able to handle this power amount i am thinking bout 400+ maybe 500. Or will it? rebuilt will it?

I have been thinking bout this, tryin to come up with ideas/combos for awhile and i need some help with it so maybe you gents can help. If not the ls6 heads what heads would be good to port and put bigger and new valves in? or is this patiot combo the way i should go? idk, The car has the 350tpi and i am sick in tired of putting money into it and gettin nothing back. So LSX has to be the way to go. I see these things putting done insane numbers with just topend upgrades, so let me no what you guys think of the partslist. I want the car to be a street friendly, not just drag, I want to be able to drive on the streets where I find the fun. So, and suggestions would very well appreciated.

K i tried to insert the picture of the crank where the spacer would be so maybe this will help to answer the ls1 crank / t56 question
but it wouldnt let me so here is a link ill try to get it figured out

http://img195.imageshack.us/i/1012464.jpg/

 

If you want a good set of heads, that will flow well, and have bigger valves in them, get a set of L92 heads. You'll have to run an LS3/L67 or Fast intake with rectangle ports though. But, you planned on spending the money on one anyways. Then, get a custom ground cam. Buying L92's would save you a lot of money on the heads, and they'll outflow the Patriots, stock. Only thing is, you'll have lower compression. You could also look into TSP's CNC'd L92's for around the same price as the Patriot LS6, and outflow them big time. On an LQ4, with the right cam, and the Fast LSXR 102mm intake, I could see making ~600 crank hp (~500 rwhp, through the 6 speed).

 

well, I wanna get that edelbrock intake, ( the dyno vid shows it making 30 more horses then the ls6 intake! ) So if i could stay somwhere in the ls1/6 route i will. Get some ls1 heads and port um, valves then that should keep a smile for a lil bit,.... right? I havnt heard to many good things obut the ls1 heads? the l92 heads aluminum? castiron? now when you say lower my compression what kinda lowering are we talking bout,... 9:5.1? what? hey do you know bout the crank thingy? if so that is my main concern,... ya no thanks though

 

Not sure on the crank thing. I've been trying to search for that too, since I've got an '02 LQ4 that'll be going into my car in the next few weeks. And, with L92 heads, the compression would stay the same as having stock heads on an LQ4, so 9.4:1.

 

ah,.... ok that sounds healthy, i looked up some stuff on the l92 heads i think i might fo with them. As far as the edelbrock intake,well that kinda stinks but i guess a FAST will have to do lol well thanks man and good luck on your build, if i find anything out bout the crank issue ill let ya no so you have a heads up.

 

I'm just about finished my 404 swap (stroked LQ9) in my 04 GTO. I can tell you now, if you go with the Pro-XT you Will have to cut your cowl to make it fit. I had to cut my hood

 

the 99 crank will have to go unless you want to get a 4l80e also as for the 02 that will work it has a spacer between the flywheel and the crank that needs to come off only other thing that will need serious attention is a crank relearn that you can get at any gm dealership