i bought a used 2003 extended cab short bed that was to have a 5.3L in it. after driving it for a few days i realized it was way stronger than my tahoe that has a 5.3. it also sounded as someone has put different exhaust in it. very strong tq off the line and stalls about 3k. so yes i bought a used truck with some stuff done to it from a car lot... well i get under it to look and first thing i noticed was there was no rear o2 sensors... there are 3 inch pipe duals ran to the stock muffler...yes the stock pipe was replaced with 3inch and they took the "y"pipe out and ran another 3 inch to the stock muffler. they cut a whole and ran it into it!!! it really sounds almost stock at idle but when you get on it, it sounds great some how. so i need to replace all of that not sure what with yet.

now the other problem is after looking on this site for months i see that the 317 heads mostly came on the 6.0 motor... so i look and looked again it does have 317 heads.. could they have came on the 5.3?

also i have hp tuners and i go and check the vcm and sure enough all kinds of stuff changed in there... speedo set at 255, gears are set at 4.10, so i know stuff has been changed

so i got alot of work to do..lol

my main thing i want to know is how can i check what motor is really in it? it is the 317 aluminum heads for sure but i don't know where the other places i can look to check the block.

the tranny has been replaced for sure also but it is still a 65 it shifts great so i will leave it alone for now.

just think i will go with long tube headers, no cats (they are not there now) to a magnaflow dual in, dual out dumped

ever hear of something that crazy!!

 

geezzz....sounds like you bought a truck off pt.net!

 

how much did you buy it for?

 

sounds like you got a pretty well modded truck, except for the muffler lol. i think you can pop the oil pan off and tell if its a 6.0?
also 317 heads never came on 5.3s only 6.0s

 

Sounds like you got yourself a hot rod that the car lot didn't know about. I would bet if they are infact 317's you ahve a 6.0 in there.. Nobody would put 317's on a 5.3, if they did, it would lose power.. You got a good deal there.. Post some pics up of it Lemme guess your from texas ??

 

well. wait.. He said he has a lot of work to do? You wanting to make it stock? your going to have less power than you have now and probably lose MPG's.

 

I'm guessing that you have a 6.0 there...

 

i got it for only 5k with 120k miles on it so it was in great shape except a small dent in the hood. a good price i think. when the way it runs i am pretty sure it is a 6.0 but just wanted to know 100% yea i want it to run dont care about it being stock. i am in Alabama. i will take some pics this weekend.

looks like to start i need to order some pace setter long tubes and a muffler.

the tires on it are new (stock) but i am going to change them to something else after i finish other stuff. you cant hardly touch it off the line without spinning both so i will pull the rear cover this weekend also to see what is in there.

 

sounds like a good deal to me, i had the same prob when i got my truck, it already had stuff done to it and had to go in circles finding out exactly what was done. good luck with it and let us know how it goes