4.3 Chevy Swap

Been wondering about swapping in a 4.3 chevy TBI for a while. Just thought I'd start a thread about it to get some of my questions answered. Basically, wondering what the total cost would roughly be? I'm thinking of getting a 1990-1991 astro van complete, so I can test drive it for power and drivability and overheating, etc., then I'll have the motor, radiator, all the wiring, all the accessories, etc. for doing the swap. Would it be wise to keep the 4l60e auto tranny or mate the 4.3 to my t-86 I have right now (and plan to upgrade to a t18 whenever money allows, but would keep the auto if I went that way instead, instead of putting auto in then getting t18 later). Is the 4.3 with auto combo too long? and will it mate to my dana 18? I can get an entire astro van for roughly 500 bucks, and I am decent at fabbing brackets and things, and a buddy can weld good. So, what am I looking at roughly for cost to get the rig back up and running from start to end for the swap? I know I could go a few different ways with things, such as headers or not, the stock auto behind the 4.3 or my t-86, so if you have any opinions, thoughts, ideas, etc., let me know, and if you have done a swap like this already, let me know what way you went with everything and why you did it that way, what it cost, and how you liked the end product. Pics are always good for stuff like this too! So post up, lets see what ya got! Thanks.

 

If you have a T-86, does that mean you have a 225 V6 now? A swap from a F134 to a 4.3L would make more sense, but the F134 was aways paired with a T-90.

 

Or as in the case of my '66, a T98.
I have also thought about doing a possible 4.3L swap. Advanced Adapters has a engine-T86/T14 adapter (http://advanceadapters.com/product/2166/712506.html) for a reasonable price (under $300) and later get the one for the T18 (a lot more pricey but not beyond reason, $400-450).

 

yes, right now I have a 225 v6 with a t86. It seems like a new (for me/rebuilt) 225 would be the faster and easier way to go, but I don't know what the cost differences would be. And it does get kind of tiring trying to find parts for the 225 vs. a 4.3, so just thought I'd open this up for discussion.

 

I'm in the process of putting a 4.3 in my '51 CJ3a. In an effort to keep things cheap I was initially going to adapt it to my T90 (I even bought a used adapter), but I recently bought an SM420 and long style Advance Adapter from termin8ed. I don't know how tight it would be in an early CJ5, but I would have a six inch long driveshaft if I tried to put a 4L60E/7004R in my flatfender!

 

Frame is already setup for V6? Buick 350 will bolt right up, and you can retrofit a GM junkyard TBI for not too much money.

 

hmm, interesting, I'll look into the buick 350 v8 then. check out power numbers and whatnot. Only thing, I really don't seem to have any extra room on the front side of the motor to add two more cylinders. My fan clears the vacuum advance by about 1/8", and there is about 1-1.5" clearance from my fan to my radiator. Do I just lose the fan and put an electric pusher fan on the front of the radiator instead? The Buick 350 v8 literally bolts right in the exact same motor mount location? And I'd assume it's evenfire, to get away from the whole funky oddfire thing, huh? Whats parts availability like for the Buick 350? It come with a big two barrel, or a 4 barrel?

 

Haven't done it, but have seen one in a Jeepster and lots of pics on the 'net in CJs. The one I saw fit like a glove. I plan on doing it if my V6 ever goes out. The engine mounts and bell pattern are the same as 225/231. Distributor is still at the front just like the V6. You can swap the grille and radiator with one from a '72+ AMC 304 for clearance, or run an electric fan as a "pusher" on the front of the radiator. The Buick 350 was before EFI, but it would be well matched for a TBI swap out of a Chevy pickup; extremely plentiful in the boneyards right now due to the recent "cash for clunkers" program (the TBI not the engine). Here's a nice writeup on how to convert a carb engine to TBI:
http://www.bustedjeep.com/projects/junkyardtbi.asp

 

The 350 will bolt in BUT you will have to cut the front radiator support out so a new mount can be fabbed closer to the grill. There is also going to be exhaust problems too.
We just went from a buick 350 to 225 and the motor and trans just bolted right up but we are also using a T90 with adapter.

4.3 and Auto, not sure there is an adapter for the D18 to 700r4 but there is one for a D300. The D300 requires a centered rearend. Autos will fit if you push the engine all the way forward and doesn't hurt to push the rear axle back a couple inches too. There are adapters for the TH350.
http://www.earlycj5.com/forums/showthread.php?t=66584

 

http://www.novak-adapt.com/catalog/kit_107.htm

Go big or go home. The 4.3L and 700R4 is sufficiently different from your 225/T86 to make the swap worthwhile. The 4.3L/T-86 in place of the 225... why bother? The Buick V8s fit easily, but I'd worry about the T86/T14 paired with one ... The Buick V8 is great in the Jeepster with TH400, but I'm not convinced it's such a great pick over the V6s with the weaker 3-speeds.

 

I would not waste the time to adapt a 4.3 to a T-86. WHEN it goes pop parts are getting darn hard to come by. The T-86 was marginal behind the 225. Start adding more torque and it's a matter of time.
Before getting too antsy, wait and see if everyone can help you figure out your existing problem.
Unless you are bent on fuel injection and a larger motor.

Remember, exhaust, wiring, cooling system, stronger transmission, computer, vehicle speed sensor adapter, motor mounts, exhaust, fuel system mods (adding return line, electric fuel pump), etc. It adds up quick.

 

If you are going to use gm power, be it a 4.3 or the 350 (the Buick 300 and 340 will also bolt in but the parts availability is about the same as the 225), I would just use the sm 465 or sm 420, both of which offer better gears than the T18, and buy the adapter to the Spicer/Dana 18. Personally, I would use the sm465 because the new adapters are less than an inch thick, gaining you a couple of extra inches for the rear driveshaft. I think trying to put any of the auto trans in will be a major headache-something akin to trying to fit an NV4500. That said, I am sure it has been done. Cost wise, there will likely only be a few hundred dollars one way or the other for all the options and my philosophy has always been to build it like I really want it even if it costs a bit more. It usually pays you back, both in fewer problems and more pleasure actually driving it. Trying to put an actual $ figure on it will be difficult as one never knows what the cost of all the parts will be unless you have them all collected before you start.