Theres one issue to take into account. I run a 27" 255/60/15.... Anything I end up with will likely be better than the current final first gear ratio of 7:40-1! I use second gear most always right now. I am researching gears to find out what is actually available, Astroperformance in Florida has a fifth gearset in the high .7 range, also there may be a Ford .74 gearset. One site I found listed it in use in 83-84 5.0 trans. I haven't found an absolute positive answer, but so far it looks like World class and NWC fifth gearsets may interchange. if so I may be able to come up with something that will be better suited than the stock .63 and .81$$$ sets. -- Mark Price Morgantown, WV 1969 AMC Rambler, 4.0L, EFI, T-5 -------------- Original message ---------------------- From: farna@xxxxxxx > Isn't your first gear 2.95:1? Most stock cars are geared so that first plus rear > axle is around 6.0, +/- 0.30 or so. A 67 199 American used a 2.6:1 first and > 3.08 rear = 5.68. The big 67 cars used the same trans with a 232 -- 2.6:1 first > but with a 3.15 rear = 5.75. The 290 (in big cars) had a 2.57 first = 5.72. > Closer to 6.0 would be about the lowest you want. The four speed for 67 had a > 2.64 first and the optional rear was 3.54 = 6.18 (standard rear was 3.15). Much > lower than 6.5 and first is about useless for anything more than getting the > vehicle rolling -- pretty much a granny gear. 3.73 + 2.95 = 6.68. that might cut > it, but you won't be using first much. Second should be around 2.10:1 (well, 67 > AMC T-10 is) -- 2.10 + 3.73 = 5.83, which would be a good starting gear. > > ----------------- > Date: Tue, 22 May 2007 19:57:08 +0000 > From: Wrambler242@xxxxxxxxxxx > > 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. > > -- > Frank Swygert > Publisher, "American Motors Cars" > Magazine (AMC) > For all AMC enthusiasts > http://farna.home.att.net/AMC.html > (free download available!) > _______________________________________________ > 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