Ok my 47 has been in the body shop for a year now so I'm just now fixing my low rear end and tranny problem. Anyway a mechanic friend of mine gave me a 2 speed powerglide out of a 69 camero and swears it will get me up to 65/70 w/o changing the rear diff. Does anybody have any experience with that and do you know if I will get any more of a top end?