Cummins NTC 290 inframe build

The housings are the same. The difference is how much they are machined down at the gasket area. The attachment on post #11 shows housing numbers. I do not know if different part numbers were on them. Casting numbers probably mean nothing. Timing is adjusted by the thickness of gaskets between the housing and the block. Google or you tube jig timing N series Cummins or something like that.
The proper way is to jig time each box, housing. Working with some 100% commission guys they would time the first one and shim the other two the same.
There is a formula for how many thousands of cam follower gaskets equal push tube height. Those guys would measure the old gaskets. Then adjust for the for the difference. If done properly it would run fine and the job would be done quickly. No timing tool is required. If they screwed up the math, went the wrong way, it would have to be done again. This requires removing the accessory drive and the starter.

 

I was thanking a 335 had a roots type blower hung on the side of it. From your information I see I am wrong. Maybe that was the 385?

 

Thinking it was a 275…? Called a iron lung if memory is correct….

 

The 335 was tapered crank. And they had after cooled versions. Aftercooler was the size and looked like a beer case/box. 350’s were flat snout cranks. Some of the first 350’s were NOT aftercooled.
Most 290’s were bumped up at first overhaul to the aftercooled 350 CPL 160. Add aftercooler and good to go. The 160 was probably the most popular and best running SC CPL at the time. Much could be done with it.

 

Yes. But it was a 743cid. Old timers called it the “two and six bits”

 

Yes Sir you are correct….

 

I think an aftercooler might make a small improvement fuel economy and power wise.
Its not a big job to add an aftercooler. There is a big pipe plug in the right rear of the block
just above the flywheel housing where coolant goes to the rear of the aftercooler.
It will have to come out to install an aftercooler. That could be the deciding factor.
I would recommend timing all three cam followers for the time it takes.

 

Ac doesn't have to be added but it will be needed to get up to the 400hp range. The ac was added to the 350’s because they were fighting the same heating problems the 335’s had. They’d get pretty darn hot in a good pull. Ac brought the pyro temps down somewhat. The 350 I have with the pump set the way it is has over time blistered the paint on the top of the cooler were the charge air tube goes into it and I hardly ever work it hard anymore. A lot of guys chrome plated the ac tops on the old 350’s and the chrome would blue. Lol!