7.3 idi in a '77 chassis

[fomoco390]

I've tried to research this as much as is reasonable and think I've figured out how to match this 7.3 into my '77 4x4 chassis. Let me run this by you guys to see if I have this straight, and solicit opinions.

7.3 from 92 F250
Bell housing/flywheel from 6.9

This should mate to my stock NP435 4-speed. It seems that the wiring should be fairly simple - pretty much wire up the starter using the existing truck wiring (same for the charging system). The pump should work off the coil wire. I think that's it?

I don't know about the engine mounts/perches yet - anyone have any experience with this? Also, I wonder if the clutch linkage will work for the 6.9 bell housing?

Thanks for any opinions.

James

 

[86truckpull]

sounds like a grate project hope to see it soon i wish i could be more help but i think your right about the bell hoouseing and transmition

 

[77f250diesel]

I've tried to research this as much as is reasonable and think I've figured out how to match this 7.3 into my '77 4x4 chassis. Let me run this by you guys to see if I have this straight, and solicit opinions.

7.3 from 92 F250
Bell housing/flywheel from 6.9

This should mate to my stock NP435 4-speed. It seems that the wiring should be fairly simple - pretty much wire up the starter using the existing truck wiring (same for the charging system). The pump should work off the coil wire. I think that's it?

I don't know about the engine mounts/perches yet - anyone have any experience with this? Also, I wonder if the clutch linkage will work for the 6.9 bell housing?

Thanks for any opinions.

James

The coil wire won't work, it's not a full 12 volts but there is another red wire in that same bundle that is ign. switched 12 volts.

The engine perches you'll have to fabricate or mod. (what I did) the existing perches.

Dennis

 

[Dieselcrawler]

clutch linkage wont work trans will most likly have to be moved back a little bit, and all the diesel bells were hydro clutch. yours is z bar.

 

[6.9l ford]

6.9l flywheel is weighted different from the 7.3l. If you use a 7.3 engine use the 7.3 flywheel.

 

[94f450sd]

i bet you can make the clutch linkages work.both styles push on the clutch fork.dump the slave cylinder and lengthen or shorten the push rod from the z bar.and weld up a bracket to bolt to the bell housing for the z bar pivot

 

[lindstromjd]

The coil wire won't work, it's not a full 12 volts but there is another red wire in that same bundle that is ign. switched 12 volts.

The engine perches you'll have to fabricate or mod. (what I did) the existing perches.

Dennis

I actually plan on doing a very similar swap with a friend's truck, only with a 6.9 instead of the 7.3, and into a 78 4x4 automatic. Which wire is the best switched one to use if not the coil wire? Is it the only red wire in the bundle? And how much do the engine mounts need to be modified and in what way? I figured I'd get it all worked out when I lined up everything in the truck, but knowing in advance helps a LOT when it comes to hybrid swaps. Do you have any pictures of what you've done?

 

[fomoco390]

6.9l flywheel is weighted different from the 7.3l. If you use a 7.3 engine use the 7.3 flywheel.

Gaaa! Really? Howso? This whole time I've been thinking/assuming they are the same. I've heard that the 7.3 is basically a bored out 6.9 with maybe better fuel. The one I have is a single mass unit, and I thought it would be straight forward.

 

[6.9poweredscout]

The coil wire should be 12 volts as long as you bypass the resistor that knocks it down....

-Jon

 

[77f250diesel]

The coil wire should be 12 volts as long as you bypass the resistor that knocks it down....

-Jon

The wire is the resistor.
If memory serves me correct it's the hot wire @ the connector going to the ign. box on the inner fender well.

I narrowed the perches (to line up with existing bolt holes) then cut them down and capped them with 5/16 plate.

Dennis

 

[6.9poweredscout]

Oh yes, late 70s ford duraspark....and the brain box. my bad.

-Jon

 

[biggin92]

You cannot use a hydro clutch fork unless you extend it for the z bar setup . i broke a bunch of linkage trying this on my 78. you have to find a fork for a z bar set up and hope it works or you have to extend the hydro fork to get more leverage out of it.Good luck on your project however!!

 

[plywood]

Just a thought here.

I wonder if you could just use an older 460 manual transmission bell, and just drill it out however "type4" did it. Then you could use the older clutch setup.

 

[biggin92]

Good thinking plywood!!

 

[plywood]

I've been thinkin' late 70s Bronco with an IDI lately.

I'll be on to something else next month.