Few thoughts from the old guy. Since your not going to be running deep rear end gears you really don't need overdrive for the street - with the combo your talking about you would turn about 3000 rpm @70mph and it's not a daily diver. That being said you could run a 350 trans - a TH 400 (equivalent to 4l80) - and if your serious about the drag racing a glide. Either would be a cost savings over 4l80 plus the savings of the non lock convertor. You are going to get what you pay for in a converter, I've seen some of the cheapy's w/ over 10% slippage.
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