[Super Steve]

ok my dad wants to put a v8 into his 89 Yj, lifted 4" on 33 bfg mudders. we were either gonna do a 304,360, or chevy 350. hes leaning towards a 304 or 360 because we've heard they are simpler swaps than a 350. will the 304/360 bolt to the existing 6 cyl engine mounts? also will the radiator be big enough to cool a v8? finally will the ax15 bellhousing bolt up to the 304 or 360?


Thanks guys
Steve

 

[Jtjwrangler]

Most people say dont waste your time with a 304. Go with a 360. You will get more power for the same cost and it will amost bolt right in. f you can find one why not a amc 401. They all share the same block. For the 350 swap you are going to need a bellhousing, motor mounts, and radiator just to start. But you can build a chevy 350 alot cheaper than any other engine out there.

 

[MadJeeperCJ5]

The 304/306 (amc V8) will not bolt to the AX15 bellhousing. There might be an adapter out there.... I don't know. Advance adapters? You guys would probably be much better buying a complete engine trans and t-case setup out of a totalled truck and go from there. SBCs are easy to find. Lots of adapters for it to. I beleive a triple core radiator be enough to cool it, depends on what you have for radiator. Compare the dimensions from the original V8's one. The inlet and outlet on the original rad might not be on the good side depending on what engine you put in. I know there are some adapter aftermarket rads for jeeps with sbc.

 

[Hackfabricaton]

Given the choice between the 304 and the 360, you're better off going with the 360 if you want Jeep power in your Jeep. But nothing really 'drops in', or 'bolts up', without some modification/fabrication.

Does your dad's YJ have the I4 or I6? If he's got the 2.5L swap in a 4.0L. If he's got the 4.2L, and just looking for some more 'oomph', I'd consider building it up. Stoker, 4.0L head, EFI. Both options are closer to 'bolt up' and 'drop in', then transplanting a 'bastard' motor.

If your dad's just gotta have a V8:

I'd suggest a 302/5.0L HO or 351W/5.8L.

In my area of the country you can pickup SBF engines all day, every day for a reasonable price. Hell there's a guy on one of the local boards that has a 351W crate motor for sale (with 8 hours of run time) for...$800! http://www.greatlakes4x4.com/showthread.php?t=60684 You'll pay hell finding a decent 350/5.7L for that price, as most of the junk I've seen is way over priced. Believe me, I'm looking for a SBC to drop into my 89 R30 flatbed. But hey, maybe you'll get lucky.

Get a wrecked F-250 or F-350 and strip out the entire drivetrain. Heck you can even use the axles (solid front, not TTB), on your YJ. If he wants to run EFI, there are few systems simpler to adapt than the EEC-IV.

Problem with the SBF is that there is limited support in the aftermarket for the swap. But it can be done:

You can build a powerful SBF for the same amount of money you can build a SBC. IMO, it's no 'cheaper' to go SBC.

 

[butch6924]

If your dad's Jeep has a 6cyl, he probably won't see much gain in going to the 304 unless he puts some time into it before it goes into the Jeep.

IMO, the SBC is the way to go. The motor may cost a bit more, but parts for those motors are avail at every gas station and cracker barrel in the country. Adapters are almost as easy to find. If you're looking for simplicity, that's got to be the way to go.

 

[Super Steve]

yes it has the 6cyl, hes looking for cheapest and simplest, we have a few 350s laying around but one is goin into the other jeep (95 yj soon to be full width) this is just his crruiser that he wants more power out of, ive done a search and found that i guy bolted a 360 to the ax15. is that true?

 

[SHARPMACHINE]

The 4.2 is the same as a 360 to bolt-up to a tranny. I removed the factory frame mounts and built my own frame mounts (perches), it was easy. I like my amc 360, it works well and was a simple conversion. I am still running the 4.2 radiator, but would probably have problems if I lived in a warmer area. When it gets to 90 outside, I am running pretty warm at times.

 

[kab5437]

why not stroke the 4.2? I know you said cheapest and easiest, but it doesnt get any easier that pulling the motor and rebuilding, its a direct bolt in too.:flipoff2: just my 2 cents

 

[CJ4U2NV]

in a CJ an AMC Vhate is somewhat more simple than an SBC swap. but in a YJ it is unquestionably easier to use an SBC 350. after market parts are everywhere for the SBC conversion and much harder to find and more expensive for the AMC conversion. you're putting an AMC motor in a chrysler vehicle, not an AMC vehicle.

then to, long term costs are WAY CHEAPER with the SBC.


EDIT: why use the ax junk? you can pickup an entire cheby truck with a good complete drive line cheaper than the adapters you'll buy.

 

[mika360]

yes it has the 6cyl, hes looking for cheapest and simplest, we have a few 350s laying around but one is goin into the other jeep (95 yj soon to be full width) this is just his crruiser that he wants more power out of, ive done a search and found that i guy bolted a 360 to the ax15. is that true?

Absolutely. ALL AMC engines through the TJ years all share the same block bolt pattern. I've heard some race AMX guys use a 6 speed out of a TJ Rubicon behind their 390 or 401.

If I were you a 360 401 swap is the easiest you can do. No drivetrain modifications can even re-use your old shafts if you position the engine correctly. Only thing you'll need are some new motor mounts (you can fabricate your own) and I strongly suggest upgrading to an HEI distributor. Can find them on e-bay all day long for $150.

In conclusion you need new motor mounts (AA $150), new distributor (Proform $150) re-use everything else. No wiring to mess with nothing.