6.9 idi in my 79 ?

[FORDMAN300]

hey guys im seriously thinkin about switchin my 79 over to a 6.9 idi diesel, i think it would defintly be one of a kind and ive seen trucks like it . but my question is is do i have to switch to a 80's model 4 spped trans ?

 

[LEB Ben]

I'd imagine you'd want as many mating parts as possible. Not much help, but here's a bump for someone that can help.

 

[FORDMAN300]

one of my friend is a diesel mechanic, he told me he's pretty sure they make a trans mission adapter i hate to loose the 70s trans mission cause if i did i would have to re do front drishaft

 

[Fellro]

The bell is diesel specific, but 460 bells have been reworked to fit, but the easiest would be to get a bell from a T19 and use it. I have heard that the T19 and the NP435 use the same pattern. The diesel bell has an external slave, so it could definitely get reworked to accept manual linkage. However, if you want to do this, I would recommend going 5 speed if you want any real economy out of it. You may well have to rework the driveshaft anyway, depending on how well you can position it. The 6.9 is rear sump, so you would have to be sure it clears everything. Might have to measure things out, my understanding is that the 5 speed and the T19 are the same length with the adapter, which should be the same as the NP435. I can get you lengths on both the T19 and ZF5, don't have any NP435 4wd units around. I recently acquired a ZF5 truck.

You knew I would be by, didn't ya Ben?

 

[77fordbornandrasied]

My buddy has a 79 f250 with an old perkins diesel in it! truck seems to be pretty good wit the diesei. only thing is that he looking to swap dana 60's into it because twice now he after getting it truck and snapping the spider gears in this front dana 44. Also with the four speed his truck has 4,11 in the rear and she is almost to slow to drive anywhere needs to go to a higher ratio (3.50) or something as the diesel already has plenty of torque to swing even with higher ratio

 

[UNRULEE]

x2 on the larger front axle, oil burners are heavy. Why not go for a 7.3?

 

[Fellro]

If going IDI, the 6.9 has thicker cylinder walls. not a whole lot of difference between the two otherwise. The head bolts are a shade bigger on the 7.3, but head studs level the playing field....Use 7.3 rockers on the 6.9 and get a bit of lift. 7.3's are well known to cavitate through the cylinder walls.

 

[LEB Ben]

i would have to re do front drishaft

In the grand scheme of things, what's a couple hundred on a d-shaft to get set up right.

You knew I would be by, didn't ya Ben?

There was no doubt in my mind.

 

[Fellro]

Factory stock, the 80's and early 90's diesels came with D44's, and the extended cab and F350's came with D50's. The D60 showed up into the 90's on F350's. Depending upon what you intend to do, it likely won't make a lot of difference. Have yet to tear out the gears on either. If doing the 4x4 detail on pavement, expect to break things. If doing it the mud, then that can be different. Mud is hard on everything anyway.

 

[FORDMAN300]

Thanks guys!