C15 Cat Question!!!!!

Both are the same engine as far as the parts to build them are concerned. The 435 can be uprated to a 550 with a flash if the driveline will except the torque.......check to see if the 435hp truck has a 1850 torque rated driveline. The Acerts like low rpm..........so I'd be looking at the 550 truck with the 3.36 gears if both have the same size tires on them........are they both on low pro 22.5's or is one on low-pro and the other on 11R22.5's?

As far as the engine and problems..........most of the major problems were worked out by the serial number range you listed in the 550. Anything later than MXS26000 has the software issues worked out. The VVA still act up, but not as bad.........flash with a PDI stage 1 program and you'll be very happy with the way it runs

 

VVA = variable valve actuation......Mr Haney can explain that far better than I could !!

VVA = PIA in my world..

 

I would be a little concerned with 550hp with a 10spd as far as i know 10spds were only good for 475hp rateing, on another note i have a 06 c15 550hp and its bin a pretty reliable motor a few small problems but nothing realy major the worst was a turbo due to the manifold spacers comeing apart and mpg ranges from 5.8 to 6.2 every quarter after 514,000 miles.

 

so what year of the cat is the "good" motor. im wanting to buy a truck thats around an 07. i was considering a cat till i heard all the problems. im thinking of goin with a cummins this time.

 

just my .02, but the best years of cat were 2003 and earlier, just my .02 of course. but the bxs/mxs/nxs twin turbo, which would be yrs 2004-2007? are decent by now most of the issues have been upgraded and warrantied, but if was buying a used twin turbo I would buy from a reputable dealer with a excellent warranty or, get the truck approved by a cat dealer for extended warranty, if available, before I bought 1.

 

I don't think that's the case anymore. Not sure what year they may have changed it but you can get a 10spd rated for 1850tq. (I still wouldn't want one but a deal is a deal)

 

thank you country29. but alot of the cats i was seeing for sell that were in the 07 had very low miles. usually around the 200 to 300,000 range. i was wondering why there were so many low mile cats for sale. then i found another forum that was telling of all the problems with low fuel mileage and power. there was also a well known problem with the bolts holding the rockers on the valve train. it seems they would break.