5-90
NAXJA Forum User
- Location
- Hammerspace
The AMC I6 can be put in, but it takes fab work and firewall mods (probably front Xmbr mods as well, and you'll have to fab engine mounts. And get the transmission as well - the AX-15 is easiest to swap in, as the AW4 is electronically controlled, and the Peugeot is only worth something as scrap metal.)
An effective (and simpler!) upgrade would be to grab the 4WD 3.1L/3.4L drivetrain out of an S-series along with the electronics - that will net you PFI (an improvement over the Weber,) additional displacement, an engine that won't make like the Exxon Valdez with oil, and you can pick up the THM700R4 (with an overdrive gear) and the NP231C transfer case (an improvement over the NP231J.)
The "Baby 904" used behind the 2.8L V6 was a three-speed Chrysler box with a GM bellhousing pattern. The THM700R4 (1988 and later, through the 4L60 used in S10/S15 and K10/1500) gives you an overdrive gear and is a stronger box. Don't get the 4L60E (later models still,) because it's an electronically-controlled box. Unless, of course, you feel like doing a second brain transplant and trying to make the wretched thing work (which is pretty hit-or-miss.) 1987 and earlier THM700R4 have a fatal flaw in them - according to GM, the only effective repair was outright replacement. Once you get a good box, the 700R4 is a decent automatic. (Not on par with the classic "grunt boxes" - THM350/400, A727, C6 - or on par with the AW4, but still rather solid in its own right.)
The advantage to the 3.1/3.4, THM700R4/4L60, & NP231C swap? The engine mounts are already in place (the 4WD/RD V6-60s all mount the same,) the THM700R4 should be simple to adapt to fit the crossmember (I haven't looked at the situation in person, but from what I recall it shouldn't be too bad,) and the transfer case can be improved without having to go to a whack of effort. You'll probably have to adapt the Tcase shifter linkage (simplify things - get the conversion linkage from Novak. I believe it's fully adaptable to nearly anything you're likely to run into...) and you'll probably have to have driveshafts made - but you'll be better off overall once you're done. The expenses should be neatly covered once you've started making use of the overdrive range in the THM700R4/4L60 (conversion shifters can be had from most speed shops - the THM700R4/4L60 is a fairly common four-speed slushbox in swaps,) and it can be cable shifted, so that takes care of that little nuisance (no worrying about rigid linkages.)
Another option would be to try to swap in a Small Block Chevvy V8 - you can get a drop-in mount cradle from Advance Adapters (bolt-in or weld-in.) This mount cradle should also accept a 90* V6 - you can score a 4.3L V6 with THM700R4/4L60 or a decent five-speed and NP231J in S10/S15 and K10/1500; or you can get the small block in K10/1500, K20/2500, and some K30/3500 (with a four-speed auto or five-speed stick and NP231C behind it.) I think the NP3500 was used behind the SBChevvy in the K10/1500 and some light-duty K20/2500, and New Process tends to make good gearboxes. If you get one with an NP4500 you will have to do transmission tunnel and firewall work, if you get one with a Getrag you may have to do transmission tunnel and firewall work. However, Getrag gearboxes are also nice and solid - so it's still an option. Find 4WD versions of these powertrains in K-series pickups and Suburbans.
