I would go with the 3.5:1. I have a 3.25 with a 5speed and am looking for a 3.5. A 3.25 would do you well also with what you want to do. There were a lot of those installed in the automatics.

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"Tell it like it is or don't tell it at all" 1964 Falcon 2dr HT, 347V8 4V, dual exhaust, 5sp, pwr assist R&P steering, AM radio, heater with defrost and 2sp fan, electric windshield wipers, cigar lighter, dlx light group, bucket seats, console and full carpet.