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#64734 08/23/2006 7:17 PM | Joined: Aug 2006 Posts: 2 Junior Member | | Junior Member Joined: Aug 2006 Posts: 2 | Hey All, I have been reveiwing this forum for the last 3-4 weeks and I think there is a wealth of info here. There is also a lot of great advice for the rookies like me. I recently purchased a mostly stock '66 3/4 with a 327 and "3 on the Tree". It is in really great shape and I don't think I need to make many upgrades (brakes, steering, AC, rear end ratio) to make it a daily driver. This post is to ask you guys give me some insight or point me in the right direction for swapping out the ring and pinion (if possible). I think I have the 4.57 rear (Eaton 10 bolt - round pumpkin), 8-lug rear axle. I would really, really like to go faster than 50 mph with the motor screaming. Is this as easy as getting a ring and pinion kit (say 3.54 or 3.73)? Any feedback would be appreciated  . | | |
#64735 08/23/2006 7:20 PM | Joined: Sep 2003 Posts: 2,384 Shop Shark | | Shop Shark Joined: Sep 2003 Posts: 2,384 | you can use a pumpkin from 67-72 automatic truck,,4.10 ratio,,welcome to the 'bolt,,brian | | |
#64736 08/23/2006 9:29 PM | Joined: Nov 2002 Posts: 1,002 Shop Shark | | Shop Shark Joined: Nov 2002 Posts: 1,002 | Fleetside is right.
The Eaton HO52 or HO72 (removeable pumpkin) are limited for gear ratios, 4.10 or 3.90. I was lucky and found a 4.10 with Detroit locker. There maybe 3.90 gears for it but they are scarce. Your best bet would be to find an overdrive tranny for it, or add the over drive to your current tranny.
Larry
I don't own a vehicle that isn't old enough to drink.
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#64737 08/24/2006 12:48 AM | Joined: Mar 2004 Posts: 734 Shop Shark | | Shop Shark Joined: Mar 2004 Posts: 734 | Yeah, nobody makes a ring/pinion for that rear. There was one guy a few years ago in PA that made a 3.90 but, it was VERY expensive and he died so I don't know if they're still in business.
By far the easiest thing to do is what 64fleet said, swap out the center for 4.11 and do a 215/85/16 tire. Your gain will not be as good as a tranny swap but, easier and initially less cost.
A .72 (or better) OD tranny will get you to 70 mph, no problem, with the stock rear. An S10 T5 with a .72 or a WC T5 from a Camaro/Firebird (bunch of these have .63 OD) would be the way to go.
I installed a .63 in my C20 and I tach 2600 at 80 mph.
-David | | |
#64738 08/24/2006 12:55 AM | Joined: Aug 2006 Posts: 2 Junior Member | | Junior Member Joined: Aug 2006 Posts: 2 | I really appreciate the input. What type of donor rear end could I use to replace the entire rear end in the truck that may allow me to have more options with the gear ratios? A tranny swap may be in the works down the road as well. | | |
#64739 08/24/2006 4:31 AM | Joined: Mar 2004 Posts: 734 Shop Shark | | Shop Shark Joined: Mar 2004 Posts: 734 | A later model 14 bolt. You'd have to fab some things up to make it fit.
A direct bolt-in would be a Dana 60. A few C20's had this rear. A guy with a Camper Special offered me one when I was in your boat a couple years ago. Since then, I've seen a couple at the boneyards here. It was a bit of a surprise as I'd only ever seen the Eaton rears. You'd have to replace the ring and pinion obviously. But at least you can get 'em for a 60.
-David | | |
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