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V8 in M37 pros/cons

Posted: Fri Apr 29, 2022 7:22 am
by M6Scout
Hi folks I’d like opinions on v8 swap , I will be over the road more than off roading, very hilly here in upstate NY.
I appreciate any input.

Thanks

Re: V8 in M37 pros/cons

Posted: Fri Apr 29, 2022 12:35 pm
by PoW
The ring & pinion in the M37 will not tolerate much more torque and road speed than stock.

I put some 250K on my diesel/overdrive M37, only ruining 13 sets of gears.

Most of the gearsets were NOS complete units back when you could get such.

When I used just gears, synthetic lube, tight or loose setup, nothing made any difference.

PoW

Re: V8 in M37 pros/cons

Posted: Fri Apr 29, 2022 4:41 pm
by W_A_Watson_II
Axles are the weakest link (I've broke MANY), I've only broke one ring gear pinion, and it was due to me abusing it and the ARB Air Locker letting go.. If you up the tire size to 39.5", you can get good speed. I run 3,000 RPM at 60 MPH.

Re: V8 in M37 pros/cons

Posted: Sun May 01, 2022 9:05 am
by M6Scout
Thank you for your reply :D

Re: V8 in M37 pros/cons

Posted: Mon May 02, 2022 12:41 pm
by 06boblee
If you pair that V8 with an overdrive trans, it will help a lot. Check with Charles at M series rebuild on the strength of these differentials, they are plenty strong if set up correctly.

Re: V8 in M37 pros/cons

Posted: Mon May 02, 2022 9:44 pm
by PoW
People just don't listen. Parts didn't break, they wore out.

The differential (spider) gears never did develop problems; the problem is the ring & pinion just won't hold up in the long run (10K mi/year) turning some 3000 rpm at highway speeds.

As far as setup was concerned, most of those that died on me were complete factory new dropins. If Dodge didn't do a good job, it can't be done.

Then again, if you never will drive it much, it won't matter.

PoW

Re: V8 in M37 pros/cons

Posted: Tue May 03, 2022 4:48 am
by sturmtyger380
The V8 will give you more top end. I would invest in getting disk brakes at least on the front. Charles offers a disk brake kit.

Re: V8 in M37 pros/cons

Posted: Mon May 16, 2022 8:51 am
by superbee70
Upstate NY here also, if you call WNY upstate.

I'm in the middle of a swap/regear. Unless you love driving 45MPH or less, especially on hills, you won't like the straight six standard axle setup for long. I'm swapping a 360 plus front and rear axles from an 89 dodge 3/4 ton. Swapping axles gets you better brakes, better gearing, better choice of rims and tires. Not a difficult swap, you either need to shorten the passenger side front axle or offset the spring 1.5". I'm not looking for great road performance but would like to drive the 30 miles back and forth to work at a reasonable speed.

Re: V8 in M37 pros/cons

Posted: Thu May 26, 2022 3:23 pm
by Kyjim
So I'm assuming they don't make any new ring and pinions for these axles? You have to excuse me i just became an owner of one and just trying to find out a lot of info. Thanks!