1966 what gears??

[losthope]

I posted this in the drivetrain section and had no responses so ill try here:


I have a 1966 chevy c10 with the stock rear end in it the front shaft part is seeping/leaking gear oil(not pouring but small spot on the ground after it sits for a week or so), so i figure it needs to be gone through, and while i have it at a shop maybe swapping in some better gears if that can even be done....since i have no clue where to even begin or if it can be done id ask you guys what can be done to my stock rearend??? I really like to keep my 6 lugs and dont have a decent welder at my house thats a rental that only has 110v, so i really dont want to get into swapping in a new rearend if i have to weld new brackets and things like that...if gears can be swapped in what would i be looking for or tell the guy at the shop what i want him to do to it??? can i just order something from summit or jegs or else where and take it to a shop to be installed? like i said im clueless on what im looking for,just want the best combination for my drivetrain setup.......Or is 3.73 gears the best with my set up and i should have the seals replaced?? i will be driving mainly in the city but would be driving on the freeway every so often.

I dont know what info you guys need but figured some might help...let me know if you need something else:

stock crate 350
rebuilt th350 shiftkit
tire size:p15/75/r15 's
stock 66' rearend (i think it has 12 bolts)...book says/numbers i found:
C14....... (3.73) (exc. positraction)........HA

thanks for any advice !!

[Calvin66c10]

I have the same set up as you and find that the truck is terrible on gas on the highway. Even at 50mph or 80km/h (i don't have a tach) but i think it runs roughly at 2200 rpm. Its not great on gas, if your looking to get better mileage and don't care about acceleration i would put highway gears in it. Like maybe 3.08s or something of that manner.

[newbe351]

I'm running 3:54 (GMC) and was thinking of going up to 3:08 just for millage. I've since stuck a Tremic 5-speed overdrive in it and kept the 3:54's. JAWS in Sacramento can set you up with anything you want. Drop by or give them a call. Really helpful guys...

http://www.jawsgear.com/

[61_FL_Apache]

3.73's are great for the track and around town, but you may find them too low. I have almost the same setup as you with a 3.08 and im very happy with that setup. Its still kinda quick off the line and I can cruise at a decent speed on the hiway.

[losthope]

thank you for the replys! someone else suggested using a calculator on the internet to find what gears would be best , maybe ill give it a shot but so far from what you guys are saying is

if im going to be driving mostly in town to just stick with my 3.73
or might want to put 3.08

and if im doing more driving on the freeway to put the 3.08's in it..

[jocko]

Yes, but. Consider the fact that your TH350 has a 2.52 1st gear (higher gear, lower numerically) than a stock 66 3-speed (2.94 1st gear, I believe). So, going with a 3.08 and a TH350 - you're off the line perf is even less than that of a stock 66 with a 3.08 and 3-speed. Just some food for thought. Your TH350 and 3.73 combo has slightly less accel off the line than a stock 66 3.73/3-speed combo for the same reason (lower numerically 1st gear in the TH350). So, in order to not risk very poor performance off the line, I'd stick with the 3.73 and suck up the mileage loss on the highway for now.

Better yet, don't blow money on your rear end (that sounds bad...) just fix the leaks, then - get better perf off the line (and I'm not talking Funny Car launch here...) AND much better mileage with an o/d trans. If you had an o/d trans - your 1st gear will feel like it has MUCH more accel (consider my T5 has a 3.97 1st gear compared with your 2.52, and we both have a 3.73 read end) while on the othe rend of the spectrum, your 3.73 will actually be a 2.6-ish with a 0.7 o/d 5th gear. The best of both worlds. And a lot more fun. My 2 cents. I'd fix the leaks and save my $$ for a T5 or 700R4, and enjoy all the things you want without compromise.

[losthope]

Thank you "jocko" that was the answer i was looking for!! ill just have it inspected and serviced, May see if my buddy will go through it with me so i can try and learn how to do it......i never messed with a rearend before i tend to just check and add oil if need be(thats even if i remember to do that)...