need trans info, which one to run???

[tucsonjwt]

I have had a 73 C20 2WD with a 454/TH400 and now have a 83 454/SM465 4spd granny and 4:10 rear with gear vendor. I never had a 4WD or monster tires, but the 454/TH400 was the best combo in a truck I have owned. I have never used the 83 to tow much, so I never really needed the gear vendor, but since you have a 4:56 rear end, I think that is going to restrict anything else you do to your truck. A 3:23 or 3:73 would seem like a better option to open up the top end speed. Gear vendor only advertises a 20% change in final drive ratio, and fuel economy, so most of your gain is in towing or performance.
The thing about the gear vendors is that they seem to hold their value very well - always seem to go quick and for a good price on Ebay, plus easy to ship because they are relative small and light, compared to a transmission. Once you get the driveshaft mod and adapter, I think you are into at least $2K used. There is a driveline place in Las Vegas that specializes is rebuilt gear vendors, but they are still pricey. I have seen a few old suburbans and pickups with an installed gear vendor for sale, so that might be an option for someone who wants one.