I was thinking of buying another rear end but I want to go original. I have 12 bolt 373s in now and I want to do some hwy driving and was thinking what hwy gears came with SD 68 Beaumont any body have any recommendations?
Agreed, if you are running an automatic with no lockup converter (as in a TH400), the 3.07 12 bolt ratio would be bearable.
I ran 3.31 with the tallest 14" tire I could buy and at 70 mph that was too much rpm for my liking if I was on the highway for any length of time.
It certainly will reduce the launch feel though if you have 3.31 or 3.55 now. If you don't care too much about bottom end, I go as far as 2.73 to make it highway friendly. I hate a roaring engine on the highway. All these new vehicles with high ratios and overdrives and lockup converters have spoiled me. I used to think close to 3000 rpm at highway speed was no big deal but it sounds awful now.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
You should hear my car Carl at 4500 RPM at 95 KM on the highway with my 4:56 gears , it's just plane insane! I have a set of 3:91 gears I am putting in as it's a GM gear I bought off a rear end shop. Not sure what they would have come in though but it's the lowest gear I can run on my 4 series carrier. I would love to run a 3:31 set up in my 12 bolt but just don't have the extra cash presently.
I was thinking of buying another rear end but I want to go original. I have 12 bolt 373s in now and I want to do some hwy driving and was thinking what hwy gears came with SD 68 Beaumont any body have any recommendations?
Hi JJ...
Another option you might consider is a 5 speed transmission. I have 373's in my '68 Z28 and with a Tremec 5 speed (.68 o/d) the rpm was reduced from 3200 at 60 mph to 2300. this of course depends on what your wheel & tire combination is.
Just saying....
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1949 Pro Street Meteor Coupe, 468 BBC, 4L80E, Narrowed 9" 3.50 posi
1966 Biscayne post, 427 L72, M21, 4.11's 16600 original miles
1966 Hemi Satellite 4 gear 59K original miles 1968 Z28 302MO, M21, 3.73's, cowl plenum induction