Does anyone know the length of the early 3.9. I think the small block mopar is 29.5 inches long and I am trying to see if I might need to set engine back or not.

 

I have a Shelby Dakota. Shelby removed the V-6 and installed a V-8 using the same k-member. Your problem will be clearance issues at the water pump pulley and the radiator. He installed a double pusher fan inbetween the radiator and the condensor coil. So if you go the same route you won't have to push the motor back.

 

Eric-It depends on what year he has. 87-90 has a different core support which made the engine compartment smaller since they didn't have a v8 option at the time. 91+ has a bigger engine compartment since they did have a v8 option. Worst comes to worst, he switches to newer model (magnum) time chain cover and water pump but people put small block la motors in dakotas of all years all the time. big blocks even!

 

Also engine wont need to be set back at all. use should be able to use factory 340 mounts. the v6 engines were basically a 318 with the front 2 cylinders cut off, so the engine mounts were the same between the v6 and v8. The only place you going to run into a problem is with the trans crossmember if your not using a 42rh or 46rh (4 speed auto)