4.8l To 5.3

memarr2001 · January 31, 2010

I have a 2002 GMC Sierra w/a 4.8L engine and either a 4L60 or a 4L80 transmission. My truck has 235K miles with NO engine problems...until now. I seem to have cracked a head or blown a head gasket.

Instead of fixing it I want to switch the engine to a 5.3L from a 2007 Yukon XL w/ 22K miles.

My questions are this:

1. Will my transmission fit this new engine?

2. Will all of the wiring work with my old wiring harness?

3. Will the '07 engine work in my '02 without major changes?

4. What else do I need to know about making this change?

I love this truck and do not want to part with it, plus it is paid for!

Thanks for your help and advice!!!!

Marty

fcknmaw · January 31, 2010

Do you already have the 5.3? If not, pass on it and buy a 6.0

P71_CrownVic · January 31, 2010

I have a 2002 GMC Sierra w/a 4.8L engine and either a 4L60 or a 4L80 transmission. My truck has 235K miles with NO engine problems...until now. I seem to have cracked a head or blown a head gasket.

Instead of fixing it I want to switch the engine to a 5.3L from a 2007 Yukon XL w/ 22K miles.

My questions are this:

1. Will my transmission fit this new engine?

2. Will all of the wiring work with my old wiring harness?

3. Will the '07 engine work in my '02 without major changes?

4. What else do I need to know about making this change?

I love this truck and do not want to part with it, plus it is paid for!

Thanks for your help and advice!!!!

Marty

There is a person on www.truckmodcentral.com that's putting a 6.0 in place of a 4.8 in his 2000 Silverado.

LINK-TMC

memarr2001 · January 31, 2010

I would love to put in a 6.0L but it comes down to $$$$. The 5.3L I found has 22K miles and it will cost me $650, which makes it a great alternative to spending more money for the 6.0L.

I will be watching the link provided on the 6.0L mod...I wish I had the money and I'd do it also!!!!

clemsonblozz · January 31, 2010

going from a 4.8 to a 5.3 is not a problem.. The external dim's are identical, tranny connection, ect..

Now, if it was from the same model year,, you'd have to have the pcm reprogramed..

But, you are going from a 2002 to a 2007,, there are some items that will most likely be not the same..

Your 2002 is drive by cable, and the 2007 will be drive by wire.. 2007 will be flex fuel, and if yours is not, I think alot of the top of the engine stiff will not be the same.. Injectors, coils, ect..

Not sure if the 5.3 and 4.8 take the same injectors, but the flex fuel and non flex injectors different.

memarr2001 · January 31, 2010

My plan was to just use all of the parts that are the same to just leave them on, and those that are different just switch from the old engine to the new. Mainly just use the block and heads from the new, switch everything else.

Silverado4x4 · January 31, 2010

If your just changing the block and heads and everything else is 4.8 I dont see a problem. The differance between the 5.3 and the 4.8 is 96.0 mm bore, 83.0 mm stroke, 9.1 compression ratio and the 5.3 has 96.0 mm bore, 92.0 mm stroke, 9.9 compression ratio.

memarr2001 · January 31, 2010

Since Clem posted I've done some checking and the injectors are the same for both the 4.8 & 5.3 and the same for '02 & '07, including the Flexfuel injectors. Will my computer match up though? And, have read a lot about Blackbear programing...where can I get this done?

clemsonblozz · January 31, 2010

cool, I thought the flex injectors had a smaller plug, thus making the harness different.. I know the coils on my silverado have the cooling fins on the top, and the ones in my tahoe don't,, so that might be something to check.. I think the truck ones are the way to go,, they are made for more heat..

Blackbear has a ad on the right side of the page, right above the bilstein ad.... My truck is stock, but everyone raves about those tunes,, and if I ever get one,, I'll get the data log cable, and get a custom tune.. If you contact blackbear and tell em what you are doing,, I am sure it's nothing for them to tackle..

good luck, and you'll love the extra torque..

Visegrip117 · February 1, 2010

http://www.blackbearperformance.com/

Prokopchuk_9 · February 1, 2010

if ur gonna do a swap, dont waste ur time with a 5.3...find an LQ4. waaay better engine platform to start out on. i replaced a 4.8 with a 6.0 in a 2002 RCSB step side. with an NV-3500 tho. it was craaaaazy. not all that much work either dude. found the motor with computer for 1200 bucks at a wrecker out of a cop suburban. took a weekend and a couple boxes of beer.

thearborbarber · February 1, 2010

Also something to think of is GM went to a higher resolution reluctor wheel for the crank position sensor at some point between the years. Getting the PCM from the donor vehicle would be very advantageous. A vast majority of the timing is based off the cps.

memarr2001 · February 1, 2010

I just checked on the CPS and it is different...thanks! $46.00 at autozone.

I checked out the link and it sounds like my plan of attack after I get it up-and-running, but how do I reprogram it to get it up-and-running.

I would really like to go to a 6.0 but I can't afford it! With my Child Support, Bills and food, not taking into account my loss of income over the past few years, I'm lucky to be able to do what I'm doing. But ALL Advice is welcome and appreciated!

thearborbarber · February 1, 2010

The reluctor wheel on the crank is also different. That has to be changed also. Is the PCM not available from the donor vehicle?

Why not just swap heads and be done since that seems to be the only problem and you are on a budget?

memarr2001 · February 1, 2010

I was just reading about that, on another board, and was thinking the same thing...But my block has 235K miles on it and the Heads will have 22K. With all of the cost for putting on rebuilt heads vs. dropping in this 5.3L engine, plus getting a relucter wheel converter, it's about the same cost.