advise

[huntingbear]

Hello, I have a chance to buy a 1986 4 wheel drive comanche for 200.00 with the 2.8 engine(not working) I understand that the 4cy would go in easy what about the 4.0

[Eagle]

The 2.5L has the same bell housing bolt pattern s the 2.8L so you can use the same transmission. The motor mounts are also the same. The 4.0L uses different motor mounts (but in the same location), and a different (larger) bell housing, so you would beed a complete engine/transmission/transfer case setup from the 4.0L. Also, the early firewall wasn't designed for the 4.0L, and the 2.5L/2.8L radiator isn't large enough to cool a 4.0L. Some 4.0L conversions have been done that didn't require much modification to the firewall, others report that fairly major surgery was necessary. The entire front sub-assembly that supports the radiator has to come out, and be replaced with the corresponding parts for a 4.0L radiator.

 

In general, a much easier upgrade for a 2.8L is a GM 3.4L V8 out of a rear-wheel drive car like a Camaro. It's the same basic block as the 2.8L so it's largely a bolt-in conversion.

[huntingbear]

With the 3.4 would you also need the replacement of the radiator?

[CWLONGSHOT]

With the 3.4 would you also need the replacement of the radiator?

 

Our trucks have marginal cooling to begin with.. YES, I would recommend a good 3core replacement regardless of how you go...

 

CW

[Eagle]

With the 3.4 would you also need the replacement of the radiator?

You should replace the radiator just because the original is more than 20 years old and probebly not working very well, but you would NOT need to replace the radiator supports and convert to a 4.0L style radiator. The 3.4L uses the same block as the 2.8L. Use your 2.8L exhaust manifolds and it's a bolt-in conversion.

 

There is an issue regarding balancing of the flywheel. If you decide to go the 3.4L route, we can address that at the appropriate time.