Before we could buy our 1985 310 I had to replace the radiator in our 1983 Winnebago so we could sell it. Central Radiator Distributor in Little Rock (phone 800-632-9638) was able to order an exact replacement for the Winnebago which is also on a P30 chassis. They were even able to source a radiator for my 1960
John Deere crawler. It appeared they have catalogs for just about every radiator made.
Air forums # 1674
1974 20' Argosy Motor Home
1974 31' Excella trailer (parting out, as of 4/1/2015 I have wheels, brake drums, windows & holding tanks left to sell)