My '98 Silverado 4x4 ext cab has served me well but the stock 5.7 vortec is just not cutting it anymore. With nearly 208k+, she's getting tired. I really need more pulling power and more hp as well. So, I've been thinking about putting a new GM crate in it. What would you guys think of a LS3 525 6.2L in this truck?
It has the 4l60e but I'm pretty sure I'll need the 4l70e or even the 4l85e if I go big.

Granted that the computer system couldn't handle a new motor so would it be difficult to switch out computers?
Or should I just go with a carb engine and forget the efi? If so, I could put a Chevy zz454 or zz502 in it with a holly intake manifold and edelbrock carb. I intend to keep this 4x4 but not put a stupid lift kit on since I won't be full out mudding it, just normal off-road stuff. Mostly street though. My main question is, which should I go for, efi or carb. I want big power in this truck and the rear axle should be able to handle it. When it blows, I know a guy who rebuilds them for nearly nothing (well, since he's a good friend he wouldn't mind). Thanks in advance

P.S.- I do not even want to tear into the engine it has now, to many horror story's of rebuilds and not worth the time honestly.

 

That is an interesting dilemma, will the truck have to pass any state emissions testing or any restrictions on how you can modify the vehicle?

Personally I would go Big block with a carb.

I am in the process of getting my parts for my engine rebuild in my 95 stepside and I am going small block, voodoo cam and vortec heads and carb but my vehicle is exempt from any emissions testing.

 

I'm not to sure about the emissions or restrictions. I'll check it, although I live in missouri so probably not but it's still worth to check. And yes, I'm leaning towards the big block as well with the carb. Just looking at the dyno graph, the 502 puts out a steady power band form low to high rpms. The 6.2L has a really uneven, choppy power band. It makes its power up in the higher rpm. Which my truck would probably be better with more torque down low.

I like the idea that summit racing has a complete zz502 for much cheaper than GMs prices. Just with more torque, I'll need a tougher transmission. Will the 4l85-e have to be used or should i go with a different tranny?

I do plan to get lighter rims, tires more suited for street, electric fans, probably a new speedometer cluster, custom exhaust, maybe lower it an inch or so, possible a scooped hood, and the list goes on lol. Hopefully my budget of about 15k doesn't go over.

I may be able to cough up enough $$$ for a LSX454. Not sure but it's possible.

Sounds like you have a cool project, sounds interesting as well.

 

Well I live in MO also, and unless you live in these areas :St. Louis City, St. Louis County, St. Charles County, Franklin County, or Jefferson County you will not have to have emission testing done.

I have not looked up the specs on the tranny but if your budget will allow it I would look into getting a rebuild or replacement to a tranny that can handle the torque.

Electric fans on a set up will help gain HP the clutch fan robs about 5-10 HP from the engine.