Hi,
First time poster although I've followed this site for awhile, its great. Anyway, I've got a 1990 F150 Super Cab short bed XLT 4X4, little over 180K miles on the 5.0 and M5OD/1356. Been kickin around a Cummins conversion for awhile, well I just jumped from the frying pan into the fire. A 105HP 4BT became available 10 miles from me, very clean, 140K miles. Includes radiator, electric fan, hydroboost, starter, alternator, power steer pump, hoses, downpipe, motor mounts , intake tubing. full exhaust and is bolted to a TH400 that is shot. I jumped on it and am picking it up tonight. I will install an intercooler and turn it up to 175HP or so. For the tranny/t.case I will probably do the NV4500/NP 241. But one question I have, does anyone make an adapter for my M5OD? I've had good luck with mine, no problems, could use a rebuild kit. Does anyone know the torque rating of the M5? I know an NV4500 is way better but if I can go with the M5/1356 I think I may try it. This will be strictly a play truck, no heavy towing besides maybe a snowmo trailer and no serious offroad work. I've got 3.55 gears at present with 31X10.5 tires. If I go to 3.08 gears it will be turning 1780 RPM at 70 mph with the NV4500. I may go with 16" wheels and 285/75x16 tires which would put it at 1650 @ 70 mph. I plan on using the original TTB Dana 44 in the front and the Ford 8.8 in the rear. I'll probably need a lift with heavier coils, right? The 4BT is about 100 lbs heavier than the 5.0 I think. A complete body off resto will be done with this so it will take awhile but will be fun Any comments on my plans so far? Thanks.

 

There is no way a M5OD is going to handle a 4BTA. I'm surprised in the TH400 tranny...

You'll need 4" of lift for 285s (33's). One of our shop trucks is a 96 F150 with a 12V Cummins 6BTA/NV4500/NP205/D60/8" Lift with 37x13.50X17 ProComp Xtreme A/Ts. Anything is possible... We pretty much had a hacked up dodge to work with.

 

Yeah, I didn't think the M5OD was a good idea although it has been fine for 185K miles with the 5.0, just had to fix the plugs on the top plate that leak. Don't think it'll handle a turned up 4BTA though, at least not for long. I'll just go with a 4500 and hopefully my 1356 TC. This came out of a Frito Lay P30 van, they originally had Chevy 350 then repowered with 4BTA but kept the same TH400. Now I've got a TH400 for another project... One question on your 6BTA F150, does it use the original Ford tach, if so, do you know how it gets a signal from the 6BTA? Thanks.

 

"repowered with 4BTA but kept the same TH400. "

I'm not familiar with the 4BTA. Is the TH400 the Chevy or BOPC bellhousing style, or is there an adapter bellhousing for the diesel?

 

There's an adapter to fit the GM tranny(chevy pattern). The 4BT is almost identical to the 5.9's they put in the Dodges. Even the performance parts fit the little 4BT. It actually weighs about 100 pounds more than a 460. The 3.55's with a 285 would be a better combo, it may not be able to run well on the freeway at that low of an rpm with the 3.08's. Of course, you can alwys add more power to make up for it.

 

I'm not sure on the Tach hookup... I didn't build the truck.

Advance Adapters (just google that name) makes a lot of bellhousing adapters.

 

If I go with 33X9.5 R15 tires with 3.08 gears it will turn 1670 at 70 mph with an NV4500 which is right about at the stock torque peak and with about 85 hp. If I can turn it up to say 150-175 HP I think it should pull those gears just fine. Does anyone have a HP/torque curve for a 1990 5.0 gasser? Its rated at 185hp/270 at something like 3500 rpm. With the present 3.55 gears, M5 and 31" tires I'm turning 2200 @ 70 with no problem at all and I don't have to keep my foot in it much to maintain 70. I'm thinkng that 5.0 can't be making much more than 100 hp at that rpm? If I can tweak the 4BT up to 175 HP at say 2500 RPM it should make about 115HP at 1670 just using a linear relationship between rpm. Probably not that simple but that's my thinking at this point. I'm sure I'll need another fuel pin for the VE pump, governor spring, maybe bigger delivery valves and injectors, intercooler, turbine housing, 3 or 3.5 exhaust.

 

Wilcap will make an adapter for you for anything you want.

http://www.wilcap.com/

 

I have seen cummins engines in stepvans that have had a factory ford small block bellhousing patten. Check ebay out. I have been kicking around basicly the same idea except I would like to install a 4bt in a 2000 F-250.

 

A Super Duty has room for a 6BT, why not use the bigger cubes?

 

Well, one good reason is I don't need them. The trucks main use is driving. I may use it to tow every great once in awhile. I am planning on installing a 3 spd auxillary transmission and a twin shifter NP205 divorced transfercase. I will have 4 gear shifters on the floor . The transmissions will take up some room. When all is said and done I should have more forward gears than I care to count. But I like to shift

 

Sounds like a plan, plus you get the 30mpg benefit you dont have with a 6BT.