Someone that did something similar to what I did...

I have a long story to tell...

I have a 1999 Chevy Tahoe LT 4x4, and was not happy with it. At 38K miles, I bought a Procharger for it. The motor was dead after 500 miles. I foolishly added a set on Gibson shorty headers to the mix, when the motor was already detonating. 6 broken piston lands later, I have learned volumes...

Fast forward to present day... The truck now has a 383 forged motor, with Etec 200 cylinder heads, a Comp Cams XR264 cam, Comp Cams Magnum Roller Rockers, the Gibson shorty headers w/ Jet Hot Coating. Electric fans are worth the $400 they cost. Some people know how bad that the stock CMFI is; it's why my Procharger checked out. I have a Holley Commander 950 MPFI controlling the whole setup. I had some custom exhaust done from the headers (all 2.5 inch pipe) to a set of highflow cats. To get the power to the tire, I got a Mega Raptor 4L60E with a 2400 stall converter.

And it passed my state emissions test to boot.

I can race my younger brothers 1.8T Jetta and just about beat him (He runs a 14.5). The truck dead hooks in the street (hence the broken sun shell in the trans thanks to the 18" wheel and tire combo I got.) Not that is could be considered accurate, but using that Desktop Dyno software, the engine combo I have is good for 410HP and 480TQ at the flywheel.

Phew, okay now, any feedback? Questions, comments, thoughts?

-George

 

'

Read my previous post... I would definately consider electric fans, I love mine. And for the love of Louie Chevrolet dump that CMFI.

 

When I had the stock bottom end and bolt-ons it was a strong running "stock" engine. Even with lots of miles (over 100,000) it ran 15.3 in the quarter. Then I put nitrous on it and ran 14.1 @101, then I had a backfire and ported my heads and put a different cam in (not to mention the fuel injection that I melted) With just ported heads and cam (LT4 hot) I put down 300 hp and 310 tq. Keep in mind this is with the same short block that I had run nitrous and had a backfire. It then ran a 14.8 at the track (crowded so only one run) but I knew it was good for at least a 14.7X. After awhile bottom end couldnt take it and the motor threw a rod................which leads to where I am now. I drive it everyday, but it does eat gas......10 in town and 16 on freeway. I'm happy, but remember that LS1's put down similar horsepower with just bolt-ons. I am real happy with the torque!!!!! I gained 70 foot pounds from just 33 cubes!!!!!! I think I can get 340 out of it if I put on electric fans, I just had to prove that it could be done with the (sucky) 1st gen vortec trucks. I'm hoping for low 14's (14.1-14.4)

 

Can an LT1 intake manifold be adapted to the Vortec heads? Or just that Holley setup?

 

No offense but a guy over at FSC akaGMC350SS or something like that said he went 14.8 with a bone stock engine...

I am heavier than you but I have been hoping for low low 15's with my 99 Tahoe n/a but I have not put the converter in yet.

I think you should run 13's on just motor not 14's.

 

Chevy Thunder17....................Finally!!!!!!!!!!

I thought I was the only one!!!!!! Our combos are very similar, and I would love to see what yours puts down!!! I have full exhaust as well. And now I will definitly install some electric fans....but ouch $400!! How much was your tranny? And where did you get it. I will need a new one soon.....the torque eats at the tranny and its slipping now. I know the CMFI sucks, but before I spent the money on aftermarket I wanted to give it a shot. I think I disproved alot of people. It's legit. making 400-420 hp at the crank, which many say couldnt be done with my system.

 

It wont run 13's its too heavy......plus wind resistance. Its an extended cab.

 

What does the truck weigh, is it a 2wd?

I went 16.3 bonestock at 83mph with slipping 2-3 shift and 3.08 gears.

L31 scene is sort of lame nobody has ever gone 12's.

 

I would need to make 500 HP to make 13's in the 1/4, and my cam choice dictated that I lose some HP in the name of torque, which is what I was in the quest for. I originally intended on keeping my Procharger, but money necessitated the sale of it.

I have the compression of the motor @ 9.0 to 1. I have just killed the built 4L60E I had. Not sure what to do now. But for making in the 400 HP neighborhood weighing in at 5600 pounds having 18" wheels and 285/60 tires, I am right about where I should be. If any of y'all got any ideas motor/cam wise, that'd be cool. I could always change the cam I suppose.

The alternative is a turbo... It's a built motor, it can take it. It was intended for A.I. (Artificial Inspiration...

 

I don't think the LT1 manifold would work out due to the Vortec style setup. I am however considering that I should change the heads and manifold to a non-Vortec setup. Perhaps that is part of the problem...