Big block M109A2

[t120r]

Hi all,

Have not posted anything in about a year. My M109 has been out in Wyoming and I get to use it a few times a year . After using it for a couple of years I have come to the point where I want power to cruise or at least keep up with traffic.

So I am thinking to just put a big block Chevy or mopar in it. Even a 500 CI caddy engine possibly. I can get the adapter plate for the bell housing of any old school bus with a BB Chevy even a dodge truck (old() for that matter

The multifuel has proven to me anyway a dog . It is slow and not inter cooled so at high elevation you have to watch the pyro gauge full time. It is turned up as far as it can go. It even has burnt a hole in the bottom of the turbo.

so what do you guys think Chevy BB or Mopar BB. I am thinking 454 or 440.
The parts are available and are cheaper to build;d then buying a dt466 or something similar.

My combined GVW as it sits with trailer is 28,600 pounds so. A rebiult Dt466 is around $6,500 but I can build a big block for about $5,000 and have 350 HP or more

I drove these in Vietnam for a while they were dogs then and they are dogs now.

Any ideas would be nice.

T120R

 

[clinto]

As someone with experience with both, I can say the Chevy will be cheaper, other than the initial cost of obtaining a good core.

 

[drgreg]

I have a 427 followed by a 6 speed in my Kodiak. Don't expect real much, it's still a heavy truck.

 

[nk14zp]

Put a 5.9 in it.

 

[Atwater]

ditto on the 5.9, around here you can pick up a decent one for around $1500, $3500 aught to get you well on the way to 350hp + 700ft

 

[wreckerman893]

It will suck the bottom out of the fuel tank and it will still be gear bound.

You might be quicker but you will not be much faster.

Taller tires will help you get a few more MPH but not much.

Then you have the issue of the single cylinder brake system.

If you have plenty of GO but no WHOA life can get interesting in a heartbeat.

The deuce and its deriviatives were not made to go fast...they were made to drag heavy loads over various terrains while being driven by young soldiers.

For every action there is a reaction.....you put more power somewhere you get more strain on something else.

It's you dog and you can whip it if you want to......just don't expect too much.

 

[OPCOM]

The caddy has loads of low end torque. Either way. Just watch the speed as stated above these trucks don't have the best brakes. It's probably fine to run 60 or even 65 if you leave plenty of room, but overspeeding the drivetrain especially with the double reduction axles increases wear and inefficiency exponentially. Most people want primarily to lower the engine RPM at a given speed so it can be driven on the highway without redlining. That said, I had no issues running slowly at 50-55 even with 11.00x20's which would provide 59MPH @ 2650RPM. The engine RPM was lowered and the whole thing was happier with less RPM at 55. The 109 is pretty heavy with that box, in relation to its cargo capacity. There's nothing wrong with the original engine except your cmplaint that it's a bit underpowered, and you'll find it's more efficient than a gasser. Bigger tires will help a lot for improving your situation. Keep in mind the deuce transmission is rated 300FT LB torque and 5th gear is a weak link. A big block can exceed the capacity easily, so watch the lead foot if you do the swap.

 

[wsucougarx]

Way off topic but I'd like to see more pics of your truck! That 109 looks outstanding. Do you have a build thread you started?

 

[bighoss0331]

do the big block

 

[wheelspinner]

2 1/2 Y/O thread revived. Now I gotta know, did this project ever happen?

 

[welldigger]

I have a Chevy Kodiak with a 8.1L (496) with a 6 speed Eaton manual. With my drilling rig mounted on the back this truck tips the scales at just shy of 24,000 pounds. I can tell you right now if your expecting mind blowing power....your barking up the wrong tree. It does have considerably more power than the MF. Considering this truck weighs double what my deuce does but expect that engine to be thirsty. I would reconsider using a dt466 or 6bt Cummins. Either way your stepping up from the MF.