'82 GMC engine swap questions

[Joes69c10]

Alright guys here goes. My brother in law has my old '82 GMC 3/4 ton that has a 250 6-cyl. and auto trans. Him being 18 he wants the 250 pulled out and has a 4.3 v-6 from a chevy astro van given to him. The 4.3 runs perfect because it's still in the van which has no title "lost in a bank loan". Is this swap even possible? If so what will it take? I'm trying to talk him into trading for a 305 or 350, but some people just don't give up. I'm not saying it's a bad idea, but what kinda problems would this be? Thanks in advance for the replies JOE

[gchemist]

Is he keeping the fuel injection? If so then it the swap is better. Read this on engine perches from I'6s to V8's. http://www.persh.org/Pickup/perches.htm
Converting to the 4.3 is like converting to a 305 or 350. My Jimmy has a 4.3 and I'm pressed with the little engine. I'm not so sure on the tranny bolt pattern. I know at least one I6 had a different bolt pattern.

[kevinr1970]

I pulled a 4.3 to put in a 305/350 in my '87.
The frame towers for the 4.3 are different from a V-8 so I am sure the I6 are different again.
Also the fan shroud is quite a bit deeper for the 4.3 vs. the V-8. I would assume the I6 is unique too.

If he is convinced he wants to do this I still have the towers and shroud...

[beaterC10]

The trans cooler lines and accelerator cable will also be different. I had an 86 with a 4.3. I wouldn't go through the time, effort, and cost to replace antyhing with a 4.3 in a full size truck.

[crossy]

I f the kid is just looking for a dependable everydday truck that does not get used to tow heavy loads then i disagree with the others and say the 4.3 is great. If it is from an 85 86 astro then it will have a carb already on it. If it is a fuel injected 4.3 the manifold will have to be changed and a suitable carb found and, also the the exhaust manifolds will most likely be differnt and on an on. _ i have nothing against the 4.3 but the swap is a lot of work and some boneyard parts will have to be found to do the swap right.
I have had good luck selling good running 4.3's so maybe he could sell that off and toher parts from the truck and buy a complete 3/05 350 truck that is rotted out or something so that all the parts are right in front of him. The guy better be well versed at turning wrenches anyway you look at it..
Alll other things considered the tranny will bolt right up from the I6.

[VTKidder]

I'm on the bandwagon with the above guys....small blocks can be found CHEEP!!! Granted, they aren't free, but for a couple hundred bucks, and some searching, you can find a 305 or 350 complete from pan to intake; just slap a carb on, hook up some exhaust and off you go.

The swap will be some work indeed, and he doesn't want to get the 4.3 in and go "huh.....thought it would have more power than this." and wish he'd gone with a small block.

[Joes69c10]

Thanks for the info guys, crazy thing is he was just offered a 305 motor in running condition for $125.00 but he passed that up. The 4.3 runs good but will need some work after a while. the whole problem is he's wanting me to help and i don't have the time to work on his truck. If it was a simple swap that would be fine, but he's wanting the 4.3 in there. Kevinr1970 I appreciate the offer I'll let you know about getting them and thanks to everybody else that has replied. Thanks JOE

[VTKidder]

Sounds like one of those deals where you'll end up doing all the work. I'd steer clear of this one buddy. Let him make the mistake of the 4.3 if he's so hard-headed about it. I know how those "hey man, can you give me a hand on Saturday with my truck?" things works. Next thing you know, you're using your tools, your garage, your time and your knowhow to put lipstick on a pig.....I've seen it played out more times than I care to remember.

[Joes69c10]

Yeah VTKidder that's what he thinks, but I'm not even gonna try to help. He made me real mad sunday because my wife "his sister" told him I would help if he 1. Helped me 2. Cleaned up after his self 3. Helped me put all the tools back up and re-clean the garage, which I might add me and my wife spent about 5 days cleaning and organizing. But he had the nerve to say it wasn't his garage so it's not his responsibility! When I sold him the truck I was nice enough to put a front brake line and mastercylinder on for him "at his expense" and all he could do was halfway primer the tailgate while sitting down and fool with the radio. Sorry to go kinda off subject guys, but I need to vent some anger. I'm get tired of letting people use my space at my house and get treated like garbage, but this stuff is gonna stop. Sorry guys I feel a little better know. Thanks again for the replies, JOE

[D13]

Just looked at an 87 GMC 1/2 ton 4.3 TBI. And the 4.3 was available carbed for 85-6 at least. Best bet is to find a complete truck in yard and check oute the throttle cable, kickowns, and score the motor towers fan shroud etc. If you happen to be heading to MI I'll take the 250 off your hands...LOL.