[Mikel]

Hello,
I've painted myself into a corner. I have a mid 1994 Chevy NV4500 that I'm not sure if it's the early or late type transmission. It has the Chevy bellhousing - I also have a breadvan GM adapter plate setup as well.

I have a Dodge CTD flywheel that is about 1/2" larger in diameter (and the ring gear is larger too) than the flexplate the breadvan adapter plate came with, so its pretty obvious this flywheel won't work with the adapter plate. From what I hear, breadvan flywheels are far in between, and I was wondering:

Since the engine is internally balanced (flywheel being neutral), could I simply turn the OD the larger Dodge CTD flywheel so it will use the smaller ring gear from a breadvan setup? I have access to a pretty good machine shop, so doing this would not be a a problem. I'm sure I can get the flywheel rebalanced fairly cheaply too. When one adds the purchase price of a different flywheel, plus shipping, this becomes a very interesting option.

If this is doable, where do I get a ring gear that matches the breadvan setup?

Any thoughts? Thanks,
Mikel

 

[BobS]

The 6BT Dodge Cummins flywheel is not as thick as the 4BT Chevy P30 Cummins flywheel. You would have to do the calculations to determine where the clutch disk would be located on your input splines. This would be in relationship to the distance from the original GM NV4500 transmission face to the clutch mounting surface of the flywheel and also the distance to the pilot bearing. In other words you would be duplicating the distances found in the NV4500 from where it was removed. Then you would need to remove the starter gear ring from a P30 Cummins flexplate and install it on your resized flywheel. You will also need to redrill and tap new mounting holes for the clutch assembly.

As I have said in past postings - stay away from the standard shift Chevy stuff. It will be the most difficult and expensive route. If you want to run a NV4500 get everything from behind a Dodge 6BT and simply bolt it together. This also gives you the heavier 29 spline output coupler to your transfer case compared to the smaller 32 spline found in the GM versions.

Let us know how it turns out. Good luck.