My friend has a 87 Dakota with the 3.9L engine and we found a 91 with the 3.9L EFI engine.

He is having a problem with a stuck rod and would like to take the 91 heads and have them rebuild before he takes it to a buddies shop next weekend to replace the heads and also redo the timing chain and some other upgrades.

Also, we were wondering if there would be any benefit to changing out to the EFI intake and 'carb' (don't know what else to call it) and if it would involve many modifications. He would only want to do the intake swap if it didn't involve too many modifications. The goal ffor the swap would mostly be to get better fuel MPG.

He is planning on keeping the truck for a while.
Thanks
KC

 

Those heads ought to be identical.
You're looking at swapping the ECM, most of the wiring harness, fuel lines, and fuel tank plus a few incidentals along with the manifold and throttle body if you want that TBI to work in a safe and road-legal way in the '87...

 

^ +1

Heads should be identical.

You need to find out if the body connectors are the same between the two year's wire harnesses and if so, swap out all under-hood electronics and wire harnesses and plug them into the existing body harness. If not, you'd have to figure out how to splice the different harnesses together or swap harnesses across the entire truck.

You need to mount the ECM.

You need the intake manifold and complete fuel system for the TBI system. Carbs, throttle body injection, and port injection all run at different fuel pressures, so you need the right one for the setup you are going to use.

Also, you may want to consider upgrading to the 42rh transmission (if you have an auto that is...) from the 32rh. Its not neccessary, but you may like the overdrive and the computer will throw codes if the transmission connectors are open.

 

Cool, thanks guys

the heads will make him happy...We thought they would work.

I'll pass on the info about the EFI/TBI, and let him make the decision
Sounds like alot of work.
KC