Old School Engine Discussion - Small Cam Cummins Driveability

1800 is fine, if your Pyro is not too hot.

Assuming a 2300 RPM limit that should be a nice rpm at cruise.

Availible power to the drives are not going to be that much after taking away all the loading. (Belts, shaft, transmission etc.) It will slow a bit on upgrades. Try using a run at the hill and momentum over it. Im not a turbo man with the boosts and all. Anything over 15 has to be good.

I don't have too much experience with that particular engine. Mine lies in the slightly newer big cams. I did have a Autocar in cement mixing once in a while but we did not drive it much because literally the Federal Court House was a few minutes down the road to pour the underground pillars, we racked up more time waiting at idle than actually driving a Autocar.

 

Compared to? The old turbos had a lot heavier wheels so they were comparitively slow to spool. It's been so long since I drove a 290, I can't remember if the old international had an intercooler. I do remember it was good for about 15mph with a 9 speed and full load up a 6% grade and very quick to overheat.

 

A 290 shouldn't have a intercooler. I drove a 77 western star with a 290 and a 9 spd back when l first started trucking in the late 80's. 1800-2000 rpm was a common cruising rpm for those engines. We would gross out at 92,000lbs so they will pull the loads. But there were good reasons why guys loved 425 CATS and 350/400 Macks at the time. I would've killed for a 13 spd back then! Lol

 

Shiny 290!!!

 

The only way to know what you got is put it on a dyno.
Then you can make decisions from what you see.

 

put a n14 intake and turbo on it with a air to air

 

I've had a couple of small cam 350's both with 5&4's-one with 4.63's and one with 5.29's. I usually ran 1850 to 2150 RPM except before a split I might take it up to 2250 plus. I always kept a close eye on the stack temperature as it would jump up pretty quick. Like the OP I tried to give it as much air as I could but that really didn't help all that much. I pulled lowboy with them hauling my own equipment usually. 5.29's with a double over would give me 62-65 mph

 

Does it have an aftercooler? Those engines like higher RPM then most people are used to today, some were factory set at 2450. Many also have a fairly narrow RPM band they like to operate in. Go through a low power trouble shooting list, you can surly find one for it on line. It is just a good idea to make sure you do not have some other problem before trying to jack HP.
If it has a tag on the fuel pump what is the CPL # ? Are the seals still on it? Surly not! Just curious.
Getting rid of the log exhaust manifold plus adding a Holset turbo were a good upgrade.
Big problem is you have no idea what you have and if it was assembled correctly. As an example it the cam is out of time 1 or 2 degrees it could have a dead spot no matter what else you do.
I cannot answer all those questions but the best way to test, flow, check and clean those injectors is recons. Unless you have good buddies at a good pump shop the price difference is not much. Check AFC, Throttle lever brake over and fuel pressure under load.
If it has good power and mileage, that was about 5-6, maybe just do upgrades when regular repairs need to be done.

 

It's a 39 year old Motor in a 43 year old Truck. That's the way they were back then. With approx 900 foot pound of Torque as apposed to 16-1800 foot pound Today..


If you want to keep up with the modern trucks Go buy a Modern truck..

Just relax & enjoy it for what It is..
Just My 2 cents worth..