Keep the 3speed or go Auto?

[davidh]

Okay, I have a 67c10 that I was told the 3speed was rebuilt. The 292 is tired and I have several V8's lying around. One is a 305 from a Fbody 80's camaro. I thought about dropping this in with the 350 turbo behind it. However I do like the 3speed behing my 283 in my 63bel air. It makes the car somewhat "peppy". I was also going to put on a 60's 2bbl roch that's been rebuilt and ditch 2bbl smog intake. I want to have the most mpg. I have ideas on both tranny's. If you guys have a 3speed V8 let me know what you think.