swap to V6 or V8?

Sorry for a nebulous question but I'd like the opinions of a few people who have done swaps in the past. (yes I've reaqd through the forums and actually searched)

I have a '53 M38A1 that will be getting a new engine. I plan to use a T350 trans and the original T90 transfer case.

I have the option of getting a 283 SBC for free from a friend (not my first choice, but free).

I would rather pickup a 3.8 (very difficult to find in these parts) or a 4.3v6--smaller blocks should equate with more room for engine placement.

My goal is simply to have a "fun" jeep for mild offroading and plowing. Eventually I may try to make it freeway worthy. I don't care about big HP/TQ numbers. Obviously a budget is of some concern. The cheaper the better but I'd rather get it done right without cutting too many corners.

I'm anticipating a custom radiator--my original is not in great shape.
Do I "need" to change to a saginaw steering setup? obviously it's better but can I get away with placing a V6 or V8 and run headers maintaining the current ross setup? One concern is my PTO winch and if changing over would create headaches with that driveshaft.

I've read up on things on Novacks site. Any ideas or recommedations would be appreciated.

 

You must mean a D18 transfer case. The T90 was the transmission. My $0.02 is to go with a V6. I'd only go with a "free" V8 if I knew it was all there and in really good condition. I wouldn't put money into rebuilding a V8 if I wanted a V6. I don't have anything against a V8, but it sounds like what you want is a V6 and I would be surprised if you didn't have to put money into a "free" V8 to get it up to par.

 

I would have to learn towards the 4.3. Absolutly a fantastic motor with a good amount of umph behind it. The 283 is also a great engine, but like dvw said, it really all depends on how much money the "free" v8 would cost unless he is a REALLY good friend and its in perfect working order. The 4.3 would also allow for a little bit more room since your using the T350 and then the length of the adapter. Just my opinion though.

 

I have a rebuilt 283 (305 heads) with power steering conversion. I also have some other additions in the engine bay. It is a tight fit with a SBC and required a few modifications. I am running the T90A with a Dana 18 T-case. No regrets on the V8. The only things I have considered changing down the road are the gears in the differentials (maybe) and maybe an Sm 465 or SM 420 transmission when the T90 wears out. How much would the 3.8 or 4.3 cost? You could put that money in the SBC and have it rebuilt. Just a thought. I don't think you would go wrong with the 4.3 or 283.

 

There have been a lot of SBC V8 swaps into CJs, so you can put the 283 in if you want to. You're going to have to modify the firewall, or the grille/radiator, or both, to get it in though. V8 plus the TH350 will make engine positioning even more critical to success.

However, the V6s are more popular today because they fit in the engine compartment more easily than a V8. And, they are way more plentiful today than in the day when the SBC swap was popular. The Buick V6 is the easiest of all, because of its front-mounted distributor. The 4.3L Chevy can be installed without any firewall mods, but not as easily as the Buicks.

The only easier swap would be an inline 4-cylinder like the Ford 2000/2300, the Chevy 153/181, the Pontiac 151, or the AMC 150.

The main appeal of the 4.3L, I think, is availability. It's a fine engine with lots of aftermarket support, and it was used in a lot of (currently low value) vehicles. Look for Astro Vans and S-10 trucks. The Chevy can come with east-to-adapt fuel injection too. Plus it's likely you're going to be able to find a Chevy pattern TH350 more easily than a BOP pattern transmission for the Buick.

There are lots of engine donors out there. If you want the V8, go for it, but don't think you have to go with the 283 because finding a better engine donor will be difficult. Plus, starting with a bare engine will likely cost you more in the long run because of the extra pieces you'll need. If you look for a V6, consider buying the whole car - hear it run, and take all the bits you need for your project. Then scrap or sell the hulk.

 

I still remain a very big believer in sbc's and my opinion is that if one is going to all the work to swap a motor, the difference in installation between a V6 & a V8 is minimal. The torque difference, even with a 283, is not minimal. If you had to rebuild the 283, I would use a 327 crank and make it into a 307-they work great in a Jeep. A short water pump is a must and a small cap distributor also helps. One thing to check is make sure the 283 is late 59 or latter with the side motor mount bosses. The blocks with front mounts only require a plate adapter which REALLY gets in the way when you want to mount accessories.

 

Note that some 283s have steel cranks, and that 307s are probably the least desirable displacement of all the SBCs. AFAIK - my connection to this may be way out of date. The 283 may have some value as a restoration engine, depending on its age and history.

 

Gen 1 SBC’s have forged cranks, up until the ’68 Gen II block when Chevy switched from forged to cast cranks and increased the main and rod journal diameters. This is also when the 350 cid was introduced.

If your friends 283 needs rebuilt don’t bother with it. You can find a rebuildable 350 and rebuild it cheaper than doing the 283, not because a 283 rebuild is that expensive but the 350 rebuild is just that cheap.
Since it isn’t my money being spent, I’d go with the 4.3 V-6. They have the same bell housing pattern as an SBC so any of the transmissions that will bolt up to an SBC V-8 will bolt up to the 4.3 and your options are wide open.

 

You know what would be fun though?
Take your friends 283 and find a 350 or 327 block to put it in making it a replica DZ302. With Camel Back heads and a factory solid lifter cam I’ve read of those being dyno-tested with much more than the 300 HP claimed by the GM.

 

As noted above, the small journal cranks were forged. The 307 was an effort by GM to get more torque from the existing 3 7/8" block using parts that they all ready had on the shelf. Most of the factory 307's used a large journal crank, but the small journal version (68) was built. There is nothing wrong with these motors-they just were not factory built with high performance options. Again, they will make a better Jeep motor than a 283. I would agree that finding a 350 is a better option if a rebuild is necessary and may actually be cheaper to rebuild than the 283.

That TH350 is going to make for a really short rear driveshaft.

 

It would have to be a small journal 327 block to fit the 283 crank. Once upon a time, I had a 69 302 engine that I was going to put in the 3B. Good (or at least better) sense prevailed and I went for the LT 350 route using the 302 block, rods and heads with a new steel crank. That engine also left a lot to be desired off road but sure would have been a blast in the sand.

 

I believe that is the BOP TH350 (Buick, Olds, Pontiac) which is shorter than the standard Chevy TH350.

 

If someone really wanted to do it, Federal Mogul actually makes spacer bearings for using an early small journal forged crank in a later medium journal block. In one of the articles I’ve read, I think it was in Super Chevy mag., that’s exactly what they did to recreate the DZ302.
But yea, a motor like that is ridiculous for a Jeep. They make their power from about 4000 RPM on up and would be a temperamental diva if forced to idle around a slow trail.

Edit: that should be Clevite not Federal Mogul.

http://www.superchevy.com/technical...909_chevy_small_block_testing/crankshaft.html

 

Honestly, I didn’t either until I learned it on this board.

 

To the OP:

If you're not going for a "special" jeep then skip the V8 idea.

My choices would be:
1. 4.3 chev V6
2. 225 odd fire buick V6
3. 231 buick V6
4. ford 2.3 inline 4

I would not consider the turbo 350 auto but some people think it's fine. You just need to be aware of the possible problems before you try it.

YMMV

 

I have built a number of these, and they are a lot of fun in the right chassis------most fun is in a Porsche 914 I did.

Anyway, to make the HP, you have to twist their tail pretty tight, just the opposite of what you need in a Jeep.

The 350 block will only work with a DZ crank due to bearing size, unless you use bearing spacers or thick shell bearings----if they still exist. Pistons are hard to find also, but you can get around this is you use the connecting rods from the 1994/5 265 used in the Impala----they are longer rods, and the difference is exactly what is needed to mate 350 pistons to the 283 crank to achieve the correct deck height.

Good luck, have fun.

 

a t350 wont allow much drive shaft length be lucky to get 11 inches not very much in my opinion

 

the chevy TH350 came in 3 different tail shaft lengths, the shortest being the 4wd model, next refered to as a short shaft came in rear wheel drive cars, and the long shaft used in trucks/vans etc. AFAIK the BOP just came in the short & long shaft version, unless AMC had a short 4wd version in a TH350. not 100% for sure AMC ever used a TH350, but they did use a TH400 and the chevy version TH400 came in the 3 sizes i mentioned earlier in this post.