So my fiance has had this dream of owning a badass 2 door tahoe. I came across an estate sale and picked up this 1996 2 door with the 5.7 vortec in it and the 4l60e transmission. It can go from 2wd to 4x4. As i am not a mechanic really myself ( i do the basic repairs like brakes,alternators belts pullys and water pumps ect) i amnot literate when it comes to building. We just moved to iowa from the east coast and i chose Karl Performance as my go too to complete this build. I figure "do it right the first time or don't do it at all". Karl suggested an LS swap. My goal is the have 500whp or more without forced induction. I know in regards to the l99 they will SWAP the D.O.D lifters and cams and elimate the AFM. Im searching for used motors and will be getting either a ls3 or l99 this week.

GOAL.... I want to keep this truck automatic and 4x4. Karl Performance said i can be tuned with a "very streetable cam" and new lifters be at 500whp or very close with a 3200 to 3600 stall. Cost effectiveness, engine recommendation and 4x4 axle recommendations would be a great great help! I wanr 500wheel horse power, be streetable (daily driver and automatic 4x4. I am having trouble finding 4x4 axles with 3.73 gears or maybe even 3.42s compatable so anywhere you guys can help would be greatly appreciated! She has no idea yet so i wanna have this all done in the next 60 days (karls said it can be done)

thanks

 

You may be hard pressed to hit that 500whp mark through an auto with 4X4 in a heavy truck without doing a rather big cam or even more.

Figure with drivetrain loss right off the bat that 420-430hp is maybe 350-360 right at the wheels. I don't know if you can get 130-140hp from a simple cam swap with exhaust work. Mid to low 400's should be no problem though.

You will need a beefy transmission and figure out what transfer case to run and I'm not sure what the shop thinks they will run for a controller. Likely has to be a E38 with that new of engine or full standalone with like holley or something. For sure that 4L60e is being tossed in a junk pile, it will grenade and can't be controlled using a new stock computer anyway.

 

Thats wha i have been reading. I assumed he was speaking of other qorked bei g added to bring it up to the 500hp make. He has not discussed how aggressive the cam is really going to be yet. I have been looking at trickflow aluminum heads but are a bit pricey. But id rather do it right first. The shop said they will recommend other parts once the motor arrives on tuesday. I know ill be doing longheadders, cam and aftermarket intake. As to get to the power level i am hoping for. What other things would you recomment from your experience that can bring me to the 490 to 500whp mark without forced induction?

as for the the transmission. Performabuilt said they can rig me up a 4l80e that can hold 850hp. That shoe be plenty do you think? As for controlling the tranny we havent discussed the controller. Would a ls3 pcm be ablw to control that? And is 4x4 more difficult to bring the hp to the ground? Biggest thing is i do not want her to have bad traction driving in the rain ect. Whats your thoughts?

 

A built 4L80 is going to be your best option for a trans. The rear gearing should depend how large you go with tires. That said, large tires are going to require more HP to turn and are a parasitic loss if you're measuring HP at the wheels on a dyno. So, the same engine and trans in a Camaro will measure more HP to the wheels than that same engine in a truck with large tires. I think your best cost option would be to select a cam that would play well with a supercharger later. Get it up and running with the new setup. Then later, when the power bug hits, you can put a supercharger on it.

 

The old TunerCat/ Jet tuner will tune the older electronic computers on the Vortec motors and trannies. Also lots of guys are doing the 411 computer swap as it was used for Vortec and LS vans.

 

You can't use a 411 computer on a factory LS3 or L99 though. Not without opening up the engine to swap reluctor wheels or having to buy a very expensive converter box. Then you are still left with a much older operating system that can't fully control all aspects of the newer engines.

All in all it's just easier to use the E38 that it came with.

 

Got you.

If doing a "plain" LS swap does give a little more latitude in the old truck/Tahoe with a little less work integrating the factory harness if the poster is not hooked on the later motors.