So in light of all the warnings about the .63 OD ratio being too high. I have two choices. Find a transmission gear set to bring the overdrive into line. Which I prefer. Second choice is to install a 3:73 rear axle, which at 70 mph with a 27" tire puts me just barely over the 2,000 rpm point. Hmmm, decisions, decisions. -- Mark Price Morgantown, WV 1969 AMC Rambler, 4.0L, EFI, T-5 -------------- Original message ---------------------- From: "John Elle" <johnelle@xxxxxxxxx> > > Snip > cruise at 76 mph @ 2400 rpm. > Snip > That works out to be 31.6 mph/1000 rpm, a number that I have found to be > pretty much about ideal or at least a good compromise. > My Donohue cruises easily any freeway speed with a Mustang T5 and a > 3.15:1 rear axle using P205-70R14 tires and > 5th is easily used at slower non freeway speeds. > My two 80 Spirit based cars with a factory 2.53:1 rear axle, the Spirit > with P245-60-15's and the AMX with P205-70-14's both will cruise easily > at freeway speeds. One with a factory stock smog legal carbureted 258 > and the other with a not so factory stock smog legal fuel injected 258 > and automatic transmissions will easily pull the hills with the > carbureted one getting just a bit poopy at the upper end due to being > under carbureted. > The P245-60-15 combination works out to about 31.5 or so miles per > hour/1000 rpm also. > Personally I would not want a rear axle in the 3.5x+ range on any of > these cars or the ones I am building. > That has been my experience so far. > John. > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > http://www.amc-list.com/pipermail/amc-list/attachments/20070522/673e5457/attachm > ent.htm > _______________________________________________ > Amc-list mailing list > Amc-list@xxxxxxxxxxxx > http://www.amc-list.com/mailman/listinfo/amc-list _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list