350 cummins question

even more than that and quite simple for a mechanic

 

You need to get the cpl # and call Cummins to see if the engine can be properly uprated. There should be a tag on the left front of the engine behind the accessory drive pulley. Most of the 400's have lower compression than the 350's. You might wind up doing an in-frame to do it by the book because of the compression. Usually turning the engine up would involve different injectors, recalibrating the pump, possibly changing the timing and maybe the turbo. A Holset turbo will help but you have to be careful if the engine has Jake brakes, you need to make sure the jakes have autolash adj. screws or you can damage the engine with the Holset turbo.(bent pushrods usually) Most of the jake brakes can be converted or modified to work if they don't already have autolash screws. Also is it a small cam or big cam? You have to be careful when turning up the fuel on any NTC engine but the small cams are really easy to mess up the injector lobes on the cam when you put too much fuel pressure against them, they don't handle the pressure well. If your compression is too high and you turn stuff up too much you might have a problem with head bolts breaking if they are too old and fatigued. I know this from experience. If you are not too far from Denver I know a place that is pretty good with these engines I could recommend, they could probably tell you what you could get away with without hurting reliability too much and what it would cost. I used to have a good idea on prices for the parts but I have not had a NTC Cummins in a truck for about 5 years now so I am afraid to guess what the parts would cost.

 

I had a friend who modified a 290 into a 400 bigcam, pulled great. I drove turnpike doubles in the early eighties with 400 bigcams that pulled better than most of the newer engines.

 

Don't get stupid and use vise-grips on the fuel return line to raise the fuel pressure. LOL

 

Why did you give him the idea???...lol

 

Doesn't everybody know that trick? LOL

 

You could just get one of them old stingers an put in it.

 

Yeah drill a small hole in a dime and put that in the fuel line....you might need the vise grips on the fuel rod linkage