Okay, here is some specifics on the stock motor size 27 x 38 mm with a 2mm shaft. I'm wanting to go as cheap as possible - realize I'm not working to build a super speed demon, just something mucho faster than stock. Basically I want to go with brushless and a nice little LIPO. I've got the transmitter/ESC/receiver part down - it's the specifics on a motor/how to mount it if i can't fit in stock config, as well as finding a rudder servo that would drop right in or if not find a way to mount it.

Back in 1988 when I got this thing new it was lucky to run 5 mins (if at all) and it would lose range within a few seconds. Was also pathetic on power, i doubt 5 mph.

Here is a picture of the bottom...