Replacing the 391 engine with a 460

[Bob Marlett]

I have a 1973 coach in wonderful condition but have always been puzzled as to why it was fitted with an underpowered 391 when the 460 would have been the obvious choice. The question I have is: what problems am I in for if I decide to replace the 391 with a 460? Will it bolt up to the transmission or will I have to have a special adaptor plate made? What other concerns should I have? motor-mounts? driveline? rearend?

[TechTalk]

Replacing the 391 engine with a 460 In the late 1960s and early 1970s, Newell built gas powered coaches with several different engines. In addition to the 391 Ford Industrial V8, coaches were built with 460 Ford V8s, 534 Ford Industrial V8s (expect 4 to 5 mpg), as well as 440 Chrysler V8s. Allison, Ford, and Chrysler automatic transmissions were used. A repower that would upgrade from a 391 to any of the above would probably require upgrading the transmission, driveshaft, rear axle, and cooling system--major challenges with a considerable commitment of resources required. In other words, probably expensive, with the additional investment not adding much to the resale value. You might consider trading coaches to get the added power. A big jump in power and performance occurred in the late 1970s with the availability of 92 Series Detroit Diesel power.