I've been noticing some good prices on F3B and F7B units lately. Are these the same mechanisms as used in the F7A, FP7A, F9A or F9B? I'd like to get some undec shells to paint and would get some of the F3B/F7B for this purpose. I'd like to heard about your experience with the interchangeability of the shells and mechs. Thanks in advance!
It also appears that the F-3 and F-7 mechanisms can share the same shell. Doesn't appear to be a fit for the FT though because of the FT overhang at the rear. So the F-3 or F-7 shell and mechanism swap should work.
Thanks Ben and John. So the FP7 is not compatible. Are the F3/7 A and B mechs interchangeable? I'm really interested in doing an F9B too. Is that a different length or can I use an F3B or F7B under the shell?
I have several F7B's (if not all?) that use F7A chassis, snd those are fully interchangeable with F3 chassis so they're all usable. Is there even an Intermountain F3/F7 "B" chassis? Or are they all chopped in the nose to accomodate A units? I haven't deshelled all of my B engines but all the ones I have are A style chassis underneath. Edit to add- No, the FP7 is far too long. Same as the FP9 though.... and think about the same wheelbase as a GP38, right?
I just bought two f7a shells from ebay in erie railroad n scale and they will not fit without some significant modifications to the kato chassis. I bought two intermountain b units, bit the bullet, rather than ruining two kato mechs. Got a deal on two undecorated kato f3 shells, so now I will have to paint them to match.
I have speed-matched an A-B-A trio of IM CB&Q F3s from a group of about 6 F3A/B units. The IM F3A and F3B units use the same mechs. I did find that that IM F3s can run at very different speeds relative to each other. Andy Tetsu Uma
