4.3L to a 5.7L

[Rcookjr70]

The donor motor is out of a 89 GMC 1500. Any major issues should I be aware of? I heard this is one of the easiest V8 swaps to do. Any suggestions will be most grateful.

[doyoulikeithere]

I heard this is one of the easiest V8 swaps to do. Any suggestions will be most grateful.

Welcome.
Your in the right place. you can probably find everything you would ever need to know right on this site, if you look for it....

[markmitchinnh]

Welcome to the site. Depending on what year your van is: You can take the stock V8 block mounts and get two pieces of 1/8 flat steel approximately 3x4 to 3x5 in size and drill and bolt your block mounts to it then bolt them to the frame mounts
set the engine in so it lines up with the transmission then mark the steel where the block sits on the steel. Then you pull it back out and drill the steel where you marked it. Bolt them to your engine block then you have your motor mounts. if you are going with a TBI system and your van is TBI I have more info. I have never done swaps newer then the TBI stuff.

[markmitchinnh]

Sorry make the steel 3x8 or 3x10

[1Gary]

http://www.jagsthatrun.com/Pages/Parts_ ... ounts.html

[Rcookjr70]

Both motors are TBI. Astro is a 1991 and the 5.7 is out of 1989 gmc 1500. Maybe installing a mild cam and the hedman headers before dropping it in but thats about it. But any suggestions are welcome.

[markmitchinnh]

Pull the computer from the truck if the numbers are 7747 you can swap it into the van, if the truck is a 4x4 you may need to buy a 2 wheel drive oil pan. so basically you will need the TBi unit , the computer, possibly the Y pipe from the truck along with the motor. You may either buy the motor mounts or make them as I did. depending on the mileage on the vans transmission. You may wish to install a trans cooler as the V8 tends to up the trans temp from my experience.

[1Gary]

You didn't post how many miles are on the 5.7.Because after a V8 is installed in these vans is so tight,I suggest you at least reseal the 5.7 with a fresh gasket set.Maybe take a look at acouple main bearings and rod bearings while you have the pan off in the engine stand to see where your at.Put the cam in the engine in the engine stand too.One helpful tip is we found with just a 2" lift,it helps to work on the engine in the future.(a 2" spacer between the sub frame and the body)It's the rubber mount that you buy that provides the lift.You might be able to get by with just a chip from the V8 ECM if the cam is within 10% of the original.While I am talking about that,you want a cam and kit not using maybe weak worn springs that are on there even if the cam source tells you it's ok.They are saying that using new OEM springs as a ref.Normally all you got to do is extend the wires and reset the TV cable.

His original post is for a rwd.

[Rcookjr70]

Yes I planned on putting in a fresh gasket set and going through the motor before installing it. The motor had 150k on it. The only reason my dad replaced it was it blew out the rear main seal. It ran great before that. Compression is good. But now that you mention it, I may just buy the master rebuild kit and go through the whole thing. Do you need to extend the steering shaft with the bodylift? And is it absolutely needed? Never done one on a van, thousands of trucks and SUV's but never a van.

Thanks for the help.

[1Gary]

Yes I planned on putting in a fresh gasket set and going through the motor before installing it. The motor had 150k on it. The only reason my dad replaced it was it blew out the rear main seal. It ran great before that. Compression is good. But now that you mention it, I may just buy the master rebuild kit and go through the whole thing. Do you need to extend the steering shaft with the bodylift? And is it absolutely needed? Never done one on a van, thousands of trucks and SUV's but never a van.

Thanks for the help.

No.With only a 2" lift you don't have to do anything with the steering shaft.The only thing you need to do is bent the e-cable bracket alittle.Overlands vans sells the rubber mounts for that.It sure does help working on the engine.You have to trim the fan shout alittle.It will allow a larger tire too.I think a 29" would fit.The rear end part of it Overlands sells the parts for that too.

The early vans like yours the engine comes out two ways.The top haft of the rad support unbolts so you can take the engine out the front.You have to have the van lifted almost on it's rear bumper to get the cherry picker in there.The other way which I admit is more work is to drop the sub frame engine and trans in all.

Now you asked me if a lift was necessary.My answer is no.There are plenty of guys who have done swaps that haven't lifted their vans.It is just something for you to think about.

The engine.Well you could just fix the main seal and let it go as is.If your reseal it that would be a good move too.What I am concerned with is if you get into too deep,you might find as a example bores that are worn and are not round,but oval.SBC's do that on the thrust side and that is normal.If you put in a new set of rings,they might not seal.

Guess you got to tell me what are your goals in this swap and we can go on from there.

BTW-this is what the rwd V8 swap mounts look like:

[1Gary]

And what the truck cast iron exhaust headers look like: