Well I found a 360 that I want to operate on and build a 408 . I was wondering if anyone else has built one with OBD1 Computer system . My truck is a 95 and the 360 I will be using is out of a 95 . Will a Mopar PCM be sufficient ? Or do I need to Order a new Flashed Computer from B&G or something to have it run Properly ? Thanks for any replies and advice in advance . My 5.2 is getting tired with over 360,000 kms and started to smoke a bit until it's warm . My plan is to build my new engine and have the transplant ready to go when I finally kill this under powered block of steel .

 

I would suggest a B&G flash for it. In fact, I wouldn't bother on an OBDI engine, too much hassle.

You will need to really be careful with injector choice and I'm pretty sure the fuel pump will need to be upgraded.

If you can swap out the harness and PCM for a '96 or later, SCT would be the way to go. That trans won't last with a 408, do you could also upgrade to a built 46re.

 

why will his fuel pump need to be upgraded?

 

The older fuel pumps are only 39psi, IIRC. switching over to a 96+ year needs 49psi.

Not sure if a 39 psi pump can feed a 408 properly.

 

Nothing to do with pressure and the pump doesn't even control the pressure, the regulator does. Flow on the other hand is what the stock pump lacks, at 4000RPM at 5PSI boost my fuel pressure would flatline at 20PSI, stock pump would not keep up. Granted I'm using more fuel boosted than an N/A motor needs at WOT, but the Walbro 255 upgrade is still a good idea. Most injectors are rated at 43.5PSI so at 39 PSI you do lose a small amount of injector flow, but unless you're cutting your injector size very close to what you need, it's a non-issue.


FWIW I would run it on a standalone but a B&G flash with some 30lb injectors would probably be the next best option.

 

Well Thanks for the response. Sounds like I would have a really tough time to get it to run right . Guess I will just rebuild that 360 and have it ready when the 5.2 gets really tired .