AMC guys HELP!!!! Very important

It looks like there are some knogable AMC six guys here so I'll ask this question. My local firedepartment has a 78 jeep (M37 I beleave) old military truck it has an generator/welder/ambliance box. The orginal engine locked up and quit running so we put a different used engine in it. The problem is the new engine dosen't have the power the old one had it works to move the truck at 40MPH the old engine would move the truck at 60 to 65 on five cylinders. This carrys many of our mosted needed stuff things like the jaws of life and the SCBA's. We must do something with it. Is it possibl we have a smaller engine in it now like a 232 and the orginal was a 258. That is my guess

What are the differences between the 232 and the 258. What parts have to be good on the old engine to make the new engine a 258. If I rebuild this engine what preformance mods can I make cheep very cheep the board will not want to spend money on preformance I'm looking for a cam or something that I can sneak in with an overhaul kit or using a higher compression head that maybe the 232 has. I know nothing about the AMC engines

I also need to know what tire or tire and rim will replace the 9.00 x 16's Accually a set off a low profile truck like 19.5's may work! Anyone know?

Thanks
Jeremy

I won't pretend to know everything about these engines, but I think the major difference is that the 258 has a bore and stroke of 3.75x3.90 while the 232 is 3.75x3.50. The 258 was available on AMC cars (don't know about Jeep) in '71. The HP figures are only modestly different, so I can't see that much of a difference happening on your Jeep if you did drop down to a 232.

Avenger supercharger makes a supercharger that they say will boost a 4.0L (258) to some very respectable numbers

Are you sure you don't have a M715 Jeep?
The M37's were made by Dodge in the 50's.

If it is a M715, your in luck. The old Hurricane 6 was a terrible engine and your better off with anything else.
Most of the guys that I know with M715 have installed a great number of different engines, since the transfer case is divorced from the transmission.

Since the truck has extreamly low gears, a small block V8 with an automatic trani would be a good choice. Along with some taller tires. We used to put 17-40's on them with no mods at all. It was like the truck was made for them.

The M715 was a serious off road truck that needs some more power desparetly.

John

The OHC Tornado 230 six was a great engine, just not enough torque to move a heavy M-715 around. Production was transferred to Argentina in the mid sixties and they were used in a Rambler hybrid called the "Torino" made by Kaiser Argentina (IKA). American mechanics didn't understand the rather exotic (for 1963!) OHC engine and generally dissed it because it was different. An IKA team took one to Nurburgring in 1968 or 69 and finished second or third in their class. The Hurricane was a 226 L-head six -- again, a work horse, but not a powerhouse. It put out decent torque, but size was an issue.

Back to the problem of the engine in the Jeep. The 258 puts out lots more torque at low speed than the 232, so that could be your problem. As noted -- stroke is the only difference. You would need a 72 or later 258 crank and rods (I think pistons too, pin height is different IIRC) to convert the 232 to a 258. Check clearance on the rods as they swing around, as they will be close to the bottoms of the cylinders. The block would probably need to be notched.

258s are easy to find in any 72 or later AMC car or Jeep. The earlier one (71 was first year for 258) uses a different transmission bolt pattern and crankshaft flange (used Borg-Warner auto transmissions 71 and earlier). You should be able to use any engine from a Wagoneer or Grand Wagoneer (360 V-8). The truck you're talking about looks like a big Wagoneer, right? If so it's virtually the same vehicle and parts will swap. Grand Wagoneers are common in salvage yards, so think about one of those 360s.

If you want to stick to an in-line, consider the newer Cherokee 4.0L inline six. If you use the EFI (not hard to do!) you'll have almost as much power as the 360. Use a 258 crank and rods in the 4.0L block and you get a 4.5L that has as much hp and torque as the 360 (with the EFI). You can use the 4.0L block/258 crank and rods with a carb as well (258 head or 4.0L head, 4.0L head is a little harder). You'd still get better low end torque and a little more power.

Military Jeep pichups were discontinued in the late 60s. They were only made for a few years.

Try the M715zone. Also the IFSJA (full size Jeep association) site has all the knowledge you will ever need. Great bunck of folks there also. I have been a member for several years, there is ove 6,000 members there now.

If it is really a 1978, then it is the civilian version of the Jeep pickup and would have had a 258 in there. you could easily have installed an older 232 as the blocks are the same.