obs 1999 tahoe build

[99thomas]

I have a 1999 tahoe which the tranny went out last year. I had rebuilt the engine earlier in the year after realizing the intake needed to be done while i was installing the new water pump. And that was after i had just installed a new 6 in bds lift and tires a couple months before.


But my plan is to build this 14 sf i have sitting here with a new posi but i;m not sure if i should stick with 3.73 which i currently have in my 10 bolt but i;m getting a new 4l80e with stand alone computer unless i can find a 6 speed setup somewhere that someone has done on this body style.

motor is my question spot, i have thought about the 383ht but not much power for the money and then there is the zz454 and zz502, thought about the ramjet 502 but sounds like there is still issues with the computer which i don't feel like sinking more money into. fuel injection/carb is still questionable but not important as this is a street rig when i decide to drive it but not used as a daily driver as its been sidelined most of the last 2 years.
I'm new to forums and i'm sure there is plenty out there on motors but whats the opinion on the best route. zz454 zz502 lsx454. along with that what about the axel ratio to keep road worthy since im not sure how much the motor matters. I guess also has anyone used or heard much about those new front axel shafts, rcs i think it is?

 

[purple 'hoe]

For the price of a create motor 502 or 454, I'd just build and swap a LSx truck motor. LM7, LQ4 and LQ9's can all be found easy. With plenty of aftermarket support out there. You will not find much info on any forum when it comes to the GMPP motors. Reason is because the LSX truck motors can be found easy, there is plenty of info on them, and ton's of performance builds. They respond well with boost (turbo or supercharged) or N/A builds.

Transmission wise I'd go with a 4l80E or even a built 4L60E. You could keep looking for a 6 speed swap, but it's not as common.

What size tires do you plan on running? Assuming you have a 6inch lift, and are running 35 inch tall tires, 4.56 gears will be the best option. Swap in your 14sf with new gears, trutrac and what not. Also, regear your front differential.

 

[99thomas]

Just has 285/70/17 right now hasnt been on the road enough yet for the 35s haha. Ive thought about the ls motors but for instant power without sc/tc it seems best to put in big block. I wanna go with just motor and no add ons. Was thinking about the lsx 376/454 motors but power bands being at higher rpm ranges makes me question since the thing will prob never hit 4000 but they seem to be built stonger. Now you said lsx as in lq9 lq4, same as the other lsx with the extra head bolts and thicker heads or no? I did just come across a 6.2 i dont remember if it was with tranny for 3500 i think the other day.

 

[95TwinTT]

The big block would be best for low end power for N/A. I would check with some of the engine builders for possible deals on exchanges.

Transmission wise, the 4L80e would be trouble free compared to a "built" 4L60

When choosing the axle ratio keep in mind that the gear ratios of the trans make big difference on performance.

4L60e ratios 1st 3.06 2nd 1.75 3rd 1 4th .70

4L80e 1st 2.48 2nd 1.48 3rd 1 4th .75

6L80e 1st 4.02 2nd 2.36 3rd 1.53 4th 1.15 5th .85 6th .67

If you can afford it, the six speed would be the way to go.....

.

 

[99thomas]

Im going to be looking into the 6 speed for sure. Im not a tranny guy by any means so anything technical as in ratios im clueless. But im not rebuilding the 60e at all. Now im sure theres a calculator somewhere but what ratio would you use with a na bb running 450-500 @ motor and a 4l80e for street use but not stuck at the line if i wanted to give it some?


Most of the builders around here are more into race motors and i know they dont have longevity built into them but on that note i want a virgin block and at that rate i could just put one together myself.

---------- Post added at 01:48 AM ---------- Previous post was at 01:36 AM ----------

Anyone know anything about the rcv shaft setups? Im not sure but do the ifs shafts interchange between the trucks and tahoes?

---------- Post added at 03:08 AM ---------- Previous post was at 01:48 AM ----------

Think id just stick with the 4l80, from everything i have found they are a nightmare with the electronics to do a 6l80/90 swap and seen them only hooked up to an ls motor.

 

[foreverfalcon40]

If you are serious someone in the NY area is selling a Ramjet and built transmission in NYC. Guy was running 13's in his limited if your interested hook you two up.

 

[99thomas]

Im serious but im in the planning stages and sinking my money into the 14 bolt i have right now. Motor and tranny a few months out. Shipping im sure would be deadly from ny to mn.

 

[foreverfalcon40]

R-O-A-D T-R-I-P

Come on down to NY, lmk drink beers and spit on some hookers.

 

[Monstar_est87]

Did N E 1 else notice 95TWINTT posted here... I heard an old wise tail some1 thought they seen him but wasnt sure... He was just a fast blur...

FF40- Pictures? A link..? Anything please bud...

 

[992dr]

Did N E 1 else notice 95TWINTT posted here... I heard an old wise tail some1 thought they seen him but wasnt sure... He was just a fast blur...

FF40- Pictures? A link..? Anything please bud...

Hah, I was just thinking holy shmoly, he's a l i v e