Buying a 1966 Suburban & have a question!!

[mfd574]

Hey everybody!
So we have decided that we are going to purchase a 1966 Suburban to do some family outings with. It is quite nice and is originally a Southwestern car. It has a 283 with 3 speed on the column. My question is does anybody know what the gears are in the suburban? We want to be able to drive it down the highway at highway speeds and not at 45-50 mph. It has the original gears in it and wondering if I will need to switch the gears out or leave them in. If they are left in what is the comfortable mph we could go with it down the highway? Any help and suggestions are appreciated!!
Thanks Guys!!
Dan

[Clyde65]

Best way to verify is to jack up the rear end. turn the wheel and note how many time you make a full circle, also while you turn the wheel notice how many times the pinion nuckle goes around too. You will need the trans in neutral also. Hope this helps. because you could have anywhere from 3.07 to 4.10, the lower the better for highway runs. Also you can consider going to a 4 speed automatic like a 700r4. but gear change would be cheaper.

[protrash64]

They will be either 3:73 or 4:10's. I've been recently driving and I'm turning 2K rpm at roughly 45mph.

[mfd574]

I kind of figured that the gears would be 3:73 from talking to another guy. So if that is the case then do you think we will need to change the gears so we can drive highway speeds or can we drive highway speeds with the gears at 3:73. If they are left is what is the things to worry about if driving highway speeds? Sorry for all the questions!
Thanks
Dan

[padresag]

[QUOTE=Clyde65;4579830. Hope this helps. because you could have anywhere from 3.07 to 4.10, the lower the better for highway runs.

let's clarify this ratio thing. the lower the nbr the higher ratio(3.07).. the higher the nbr; the lower the ratio (4.11)
the lower(numerically) the better for highway the better; not necessarily true as you can go past the point of optium whereas you don't have the power to pull those gears. you might find that a set of 3.73 may be more efficient for your truck
ron

[Captainfab]

More than likely that Suburban will have 3.73's....mine did, although it was originally a 283, powerglide Burb. With 3.73's and a typical height tire of around 28" the engine will be turning around 33-3400 at 65-70 mph. Not exactly ideal for optimum mpg's and long engine life. I switched to 3.42's and the engine is still turning 31-3200 at 65-70 mph. One thing you can do to lower the rpm's that is realtively easy is go to a taller tire. A set of higher rear gears would be the next least expensive, but that 283 doesn't make much torque, so your performance may suffer, depending on just how high of a gear you choose. The best solution, IMO would be a OD trans, such as the 700R4. Although more expensive, it is the overall best solution to lower engine rpm's and better mpg's while keeping that 283 in it's power band.

[oem4me]

I have a 66 pickup and a 65 Suburban, both of which came with the 3.73 rear gears. I believe that gear is what was assigned to the vehicle when nothing was specified on the order sheet. Both the truck and the burb are not bad on the highway.
I also have a 3/4 ton truck that came with 4.56 rear gears and that was a joke. totally intolerable. Ended up swapping it for a 4.10 and 3spd O.D. trans, and now it's OK too. The O.D. does help a lot though.

[mfd574]

oem4me, Did you keep the gears in your suburban or switch them out? If you still have the 3:73 gears do you drive it on the highway without any problems in your oppinion. Also is yours an auto or manual?
Thanks

[oem4me]

Originally Posted by mfd574

oem4me, Did you keep the gears in your suburban or switch them out? If you still have the 3:73 gears do you drive it on the highway without any problems in your oppinion. Also is yours an auto or manual?
Thanks

Didn't touch a thing in the burb. It has a 283 and granny low four speed manual. I'm really not too fond of that noisy trans, but highway travel in 4th is good ...well, good enough anyway. The whiny trans (1st thru 3rd) is much more of an issue than the rear end.
If you are expecting relative silence like a newer vehicle, then you might be disappointed. But then again, at least in my opinion, road noise, whistling vent windows, am radio, and so on, is all part of the vintage truck experience.