engine modification or engine swap

Discussion in 'Trucks and Trailers' started by ADMIREDLAWNS, Jul 12, 2007.


    ADMIREDLAWNS LawnSite Member
    Messages: 39

    I have an 2001 Silverado 1500 2wheel drive, it has a stock 4.8 liter. I recently purchased what would be an enclosed tandem 5x12 & ii gave the motor a run for its money on the hour & half interstate drive back.

    Alot of the problem was the rearend gears, that I will be replacing. But I was also looking for opinions on if I should do some modifications to get more torque or just by a GM crate motor. I am still upside down in this truck so trading it in on a new one is out of the question for a while. The next one will be a box truck.
  2. MarcSmith

    MarcSmith LawnSite Fanatic
    Messages: 7,157

    do the gear swap and then reflash the PCM for the proper gear ratio... and then see what happens... putting some gears will hurt your fuel economy, but give you some grunt... if you do gears, I might recomend a a new diff with posi-trac if doesn't already have it.

    Really though how bad is it...does it tow the trailer, and it just seems sluggish, what kind of driving are you going to be doing. if its alot of highway, i woudl not touch it...once you are rolling set it at 60 and slugon downthe road. or around town were you need some low end grunt to get the rib moving, in wich case you coudl drop in some 410 gears....

    A gear swap will be the easiest,, still not something you could do your self, getting it all lined up isn't for the faint of heart plus you still need to reflash for the correct gear other wise your tranny will not shift at the right time and and you speedo will be off. after that I'd look into a differrent cam or exhaust, and Id do exhaust first and headers (cheaper) and something you can do on your own. these newer engines when you start tinkering with them, you almost need a computer degree...when you open them up...

    An engine swap would not be my first choice...a crate motor will set you back 3 large plus time to install...., you'd be even more upside down...plus when it come time to sell it and the engine doesn't match the vin, it will raise a few eyebrows and may affect resale value

    plus you could do gears, and exhaust for about a grand....

    ADMIREDLAWNS LawnSite Member
    Messages: 39

    Thanks for the input Marc. I called Jegs today & got prices on cold air intake, exhaust, gear & power tuner. This will set me back $1500 plus installation. This combo will give me about 40hp & 50ft/lbs of torque.

    I will be doing mostly inner city driving, i'm on the inner state maybe 10mins a week. This should help on everything I was trying to do.
  4. muddstopper

    muddstopper LawnSite Silver Member
    Messages: 2,341

    I'm guessing the truck has an auto tranny, cant seem to find a stick model any more. My suggestion is to not do the engine and exhaust mods until you have done the gear change, those little automatics dont handle power upgrades to well. I also suggest you add a larger tranny cooler to prevent the poor thing from over heating. Depending on what gear is already in the truck, a lower ring and pinion might also require a new carrier. typically, with GM, the 3:41, 3:73 and 4:10s ( my ratios might be off a point or two),all use the same carrier, but will need to be shimmed for proper gear mesh. 4:56 and 4:88's will require a new carrier if you truck has the higher gears. You will need someone to flash your ecm's and tcm's to get your speedo correct and to make sure the thing shifts when its supposed too.
  5. MarcSmith

    MarcSmith LawnSite Fanatic
    Messages: 7,157

    the power tuner won't do squat, except allow you to change gear ratios. I had a 94 impala with the 5.7 lt1 I got the hypertech III noticed zero change in 1/4 mile times. but once I got rid of the 3.28 and went ot 3.73's woo doggy... it felt like the car had loss about 500lb of weight...I ended up going with a dedicated tuner program and a laptop...but i was racing and was swapping tranny's out twice a year...god I miss that car...

    what tranny do you have? if you have the 4L60E get an extra cooler and install a shift kit...the 4L60E isn't really rated for towing...it will heat up quit...the 4L80E is a better truck transmission with a lower final drive...

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