Chevy & GMC Vans

Okay everyone. I'm doing some bench racing. The top end gave out on my 2002 AWD. I think even one of the heads are cracked. She has 365,000 miles so I really want to just replace the engine. I called a couple yards and can get an exact replacement 4.3 for $450 or I can get a 5.3 with 87,000 miles from a 4x4 1500 with computer for $500. I don't know much about these newer motors. Would they use the same AWD V8 conversion mounts or do I need to fabricate something? It sounds easy to me but I'm sure I'm missing something. Any experts out there?

The 5.3 wont bolt to your transmission is the first problem I see. The motor mounts will also be different. That would be a good swap as swaps go IF you get the complete engine/transmission from a 4wd truck along with the computer and all its wiring. Otherwise I'd slip another V6 into that thing. Stan Millard

The transmission won't bolt to it? I thought they both used 4L60e's? Did they change the bell housing or something? Maybe they have removable bell housings? They offered 4.3 v6's in a 2001 C1500. That's the same drivetrain as the Astro, Right? Am I missing something else?

What V8 engine would bolt to my transmission setup? 4.8, 5.3, 6.0? LS1?

5.7

Logan wrote:The transmission won't bolt to it? I thought they both used 4L60e's? Did they change the bell housing or something? Maybe they have removable bell housings? They offered 4.3 v6's in a 2001 C1500. That's the same drivetrain as the Astro, Right? Am I missing something else?

What V8 engine would bolt to my transmission setup? 4.8, 5.3, 6.0? LS1?

None of the new gen III engines bolt to the older transmissions. The bolt pattern on the rear of the blocks is different. The newer 4L60E transmissions have a removable adapter between them and the engine. You could probably change that to a gen III one but I'm not sure about the flex plate/flywheel/torque converter.

My understanding is the stock transmission can be used but adaptors may be needed. I found this thread over at LS1Truck.com. (There are others talking about the same thing, but I didn't take the time to find them.)
http://www.ls1truck.com/forums/lsx-truc ... tions.html

I seem to recall the transmission bolt holes all line up except for one, but lots of folks have run with one missing bolt with no issues. (I also seem to recall there is a cut-off date on which 4L60e's can be used and I think it is around 96. I think that is when the removable bellhousings came into play. I'm a bit foggy since I did my initial research more than 2 yrs ago.)

This is my swap... unfortunately I haven't tried to bolt my 5.3L to my transmission to know for sure...

As for motor mounts, it's true the regular AWD V-8 swap mounts won't work. But... I wonder if they would work if combined with a set of LS plate mounts designed to provide a normal small block mounting configuration. (The plate mounts allow a LS series motor to mimic a regular small block and bolt in to any GM application that had a small block.) I had a link to these mounts from advanced adaptors, but can't find it now. Other companies also make these mounts and I suspect a diagram is on the web somewhere so anybody could have them made...

The next question though is exhaust manifolds... My 5.3L manifolds look to dump pretty close to where my 4.3 manifolds do. This is critical on the AWD and there isn't much room for them to go anywhere else. If it isn't right, headers will be needed... and I don't have a clue which application would work.

Okay, cool. Thanks Matt. I think I'm going to do it if I can get the MONEY borrowed. I talked to my guy at the J/Y and he says I can get the 87,000 mile 5.3 with transmission (without the transfer case) from a 2001 4X4 silverado for $1000. Including computer and wire harness. I'm gonna drop the subframe and may do a body lift at the same time. My only real concern now is the accessories.
I agree the LS adapter plates should work fine (in theroy). I'm gonna hang around ls1truck a little more too.

Wasn't there a guy somewhere around here that did a 4.8 swap??

If you can, get the vin number from the doner truck as well. On my Cali trip with the LS1 Astro, the MAF screwed up and the local Chevy dealer in Little Rock just used the doners vin number that I had stuck right over the test port under the dash and had the answer in a matter of seconds. The techs "test ride" took three times as long as the work ;-)

That's a great idea Stan!!

I talked with Mike at Advance Adapters and P/N 713088-P is the plate adapter that changes the 4 bolt square patterns on the 5.3 to and traditional small block 3 bolt triangular pattern. Which means I can install the AWD V8 mounts onto those mounts!! YAY!! One problem solved! A million to go!!

Look at my LS1 2wd swap and you'll see what to mod on the battery box/puter holder to make the gen III puter fit in the Astro spot. By using the truck engine you don't have to change oil pans, make 240 splices in the wiring to get the computer to fit in the Astro, I think the fuel systems are the same and they weren't on the LS1, since both vehicles are at least 2000 models you won't have problems with the fuel gauge like I had installing a newer engine in a '98. You may have problems fitting the ignition coils with the truck inlet manifold but maybe not. It's something to think about tho. That's about it off the top of my head, Good luck...

.... this maybe be off topic but stan i think your going to hate me, i'm going to bug you soooooo much in the future that LQ9 idea is still rolling around

HaHa, maybe Logan will have his going by then and take some pressure off..

I DID IT!!! I'll be picking up the motor and transmission combo sometime next week. I'll be tearing my AWD apart this weekend. My goal is to have it up and running by at least Christmas!!!! I'll post pictures!!!

Awesome Logan! Can't wait to see pics and see how she performs!

when i come back i'll be lookin' for pics i'm going to be following this