As Hank said pick a trans with the right ratio. You need to know for sure what your rear end ratio is. If you are lucky it will be on a tag on one of the differential cover bolts. If not it may be stamped somewhere on the center housing or one of the axle housings. It will for sure be stamped on the ring gear. $200 isn't bad for a Saginaw 4 speed with a Hurst shifter if they are in good shape. I like the 3.11 first gear for my pickup with 3.55 rear end and 30" tires. My 270 GMC likes to run a 3000 RPMs but I like for to run closer to 2000. With OD I'm at or near 2000 between 70 &75 mph. Here are a couple of tables you can play with to help you sort things out. And again as Hank keeps saying there is the whole Borg T5 tranny swap. That may be easy in your case if you have room for the long tail shaft and don't need the short S10 tail shaft so the shifter clears your seat. But there are some changes. The saginaw should bolt right in. Beater
