V6 to V8

[SECA]

My brother has a 90 ram with the v6 and automatic in it. He picked up a 78 318 jasper motor and would like to install it. The guy that sold it to him fed him a line and said that all he needs to do is get a 90 distributor and put the motor in and that's all she wrote. Believe it or not the guy also told him that even though the 318 has a carburetor he could just hook the fuel line to it and it would be fine.

I am trying to convince him to just rebuild the 3.9 the truck afterall has 220,000 miles on the tranny and rear end

Can you guys shed any light on what might be involved in replacing the V6 with the V8

Thanks for your help

[Dodgevanman]

Most of what the guy told him is crap. Yes the motor will bolt in, but if your brother wants to keep the FI, he'll need the intake and TBI unit off of a 318...and computer. If you find a donor engine to get the parts from, he will need the distributor. Or he can just order a new one.

[SECA]

Most of what the guy told him is crap. Yes the motor will bolt in, but if your brother wants to keep the FI, he'll need the intake and TBI unit off of a 318...and computer. If you find a donor engine to get the parts from, he will need the distributor. Or he can just order a new one.


Thanks for the response!

So if I understand you correctly if he decides to stay fuel injected the following applies

existing fuel pump to remain
new TBI and Intake
New distributor
New computer



If he decides to go with the carburetor

New fuel pump - can he just pull the old one out of the tank and pitch. Should he use a mechanical or electronic pump?

What combination distributor/computer and wiring harness would he need

This is going to be a real mess for him as he does not have the kind of money needed for this swap

[Dodgevanman]

If he decides to stick with the FI, he can stay with the pump in the tank. It may be easiest just to go to a junkyard and find a donor truck to pull the intake, TBI, and computer off of. One more thing to add is that he will need the V8 engine wiring harness as well.

If he goes to a carburetor, he cannot use the in-tank pump. I would recommend an Edelbrock Performer intake and Edelbrock 600cfm carb. w/electric choke. Installing the mechanical pump would be easiest. Mopar Performance sells a complete electronic ignition kit, but your brother would have to make a wiring harness for the ignition system.

[SECA]

Vanman you have been a big help I appreciate it!

If he stays with the tbi what is so different between the v6 & v8 wiring harness?

Would the tbi from the old 3.9 work on the 318?



Wow in the old days all he would have needed was for the motor to bolt up with the tranny....

Thanks again very much

[Dodgevanman]

The more I think about what I wrote, the more I realized I was talking about multi-port injection. Duh!

In fact your brother may be able to use the throttle body unit itself. The reason I said that he may need the V8 harness is because there may be differences in the connectors to the computer, etc. But he can surely try and use his existing harness and if it doesn't work, then go and get the V8 harness.

[SECA]

Thanks again Vanman. I will let you know what becomes of it