4bt Conversion
 

Hello all i have a 1989 F-150 4x4 single cab short bed truck that has a 3 inch lift so i have beefier front springs and shocks a 351 Windsor under the hood and a 3 speed C6 trans with a b&m shift kit, as much as i love the motor i hate the gas mileage. I have been interested in a cummins conversion for quite some time now and i would like to get some opinions on this, like would would be the rough estimate for the swap, would my C6 tans work? where would i get motor mounts and all any help is appreciated :U:

Welcome to DB!!

I don't know if the c6 will bolt up but considering it will you will spend about $5000. The 4bt's run about $3000 to $4000 for a good low milage used or rebuilt. and the rest on misc parts. Probably have to build the motor mounts.

This is a good website.... www.4btswaps.com

Dito on the 4BTswaps site. I was there as Driverswanted for several years and the TDR conversions site before that site started up.
For checking out an engine and transmission combination driveability I like this site's transmission calculator. it revealed that my NV4500 5sp was going to have problems shifting from 3rd to 4th unless I increased my upper RPM limit on the governor.
Transmission Calculator - Z Design Studio
It's a real nice interactive program. Make a slight change to any parameter and you can get a good visual on where your shift points will be on the RPM range.
Drop your gear numbers, axle ratio and tire sizes in it and set your max RPM to 2800 and 3000 (if you install the 3K spring in the pump). BTW some of the 4BT engines are governored at 2,400. Those definately need the 3K spring in the pump.
Figure that you will want your minimum rpm shift to be around 1500 rpm with your vehicle weight. Your's is pretty simular to my 1985 Dodge W150 in weight. Below 1500 you won't have adequate acceleration and won't be a happy camper.
Oh, just remembered that there is a 3200 spring. It makes a world of difference with some of the transmissions.
The 4BTA is a very worthwhile project. I have my 4BTA making that same H.P. and torque as a stock 1989-1993 Dodge 6BTA and it only took a screwdriver, two wrenches and a 3200 rpm spring inside the pump.
Good Luck.

Hey ImSoAmish, do you have a link etc to your Ram w/ the 4BT. You have already done the swap that I'm wanting to do on my 84 W100 Ram.

I'll look it up at work today. I think you have tt join the 4BTSwaps.com forum to see my posts of pics

Yeah I browsed the site last night but only for a bit. I saw where the guy had done it on the ramcharger but I think he was doing more than needed to be done. I hope I don't have to cut a new tranny tunnel cause that would mean I would have to modify my T-case as well.

Mine is the buildup thread named: "4bt in 1985 Dodge Ram Prospector shorty"

4BT in 1985 Dodge Ram Prospector shorty - Cummins 4BT & Diesel Conversions Forums

You don't have to modify anything on the crossmember unless you have a forward positioned oil sump. Even with that you can buy a back side oil pickup and reverse the pan.

Is the W100 on the same frame as the '85 W150?

Yeah, the springs are what was different, W150 had a slightly better payload and towing over the W100. But I have swapped out my springs for W150 4" lift springs.

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Thanks I skimmed through it, as I have to work tommorow, but the 4BT looks right at home in our engine bays. I've heard most of the 4BT have chevy tranny mounts. I'm lookin' to stay Auto so I'm gonna have to read up on my Chevy trannies if that's the cause. My buddy found a 727 w/ a small block chevy bellhousing in a junkyard and this would seem like the ticket but if chevy has a 4 speed Auto that isn't computer controlled that may be better.