Originally Posted by flattracker
Thanks for the input. One really has to start with a Cummins already from a Crown, since the oil pan, oil pump, oil pump pickup,compressor, and bell housing are special to a Crown. The rest of the engine is the same as what came in OTR trucks. The replacement engine in my "new Crown" came out of a Peterbuilt. When researching the issue of re-powering mine after the main bearing failure, the Cummins parts book listed only one engine block, but two oil pans, one being the type used in Crowns. I know that later they replaced the cast oil pan with a stamped steel one so technically there are three different oil pans used in the Cummins. The other issue may be in the differential, since with 4.10 gearing one runs out of RPMs at 63 mph. (at least for a Cummins)
For Detroits too. 63mph is what you get at about 2250 rpm with 4.10. Period.
That's why I recommend a rear-end ratio change or an overdrive transmission.