Stock rear gear ratio info

[SS Tim]

Here is a 70 C10 power team chart for you. It really helps to post what year and series you have when asking a question like this.

[Olive1970]

Thanks Tim, but yes it is a 1970 C10. I didnt know if mine had a different ratio than 3.07 because at 75mph the truck runs at about 3800rpms or so. I do have a built TH350 and 2200 stall converter however so that is probably part of the higher rpms.

[X Baldwin Motion]

Originally Posted by SS Tim

Here is a 70 C10 power team chart for you. It really helps to post what year and series you have when asking a question like this.

Tim (or anyone) do you have a chart like this for a 68 K20?
I have a burb that was a 6cyl 4spd and a pickup with 327 240hp 4spd
They both have the 10 bolt rear.
The truck screams in 4th gear at 50mph
Thanks

[SS Tim]

Originally Posted by X Baldwin Motion

Tim (or anyone) do you have a chart like this for a 68 K20?
I have a burb that was a 6cyl 4spd and a pickup with 327 240hp 4spd
They both have the 10 bolt rear.
The truck screams in 4th gear at 50mph
Thanks

Thats an easy one, 4.57:1.
All you needed to do was click on the link in my signature, most are there.
http://67-72chevytrucks.com/vboard/s...05&postcount=5

4.57 gears spinning a 31" (stock 7-17.5)tire @ 50 mph = about 2475 rpm, that isn't exactly screaming. The indirect drive T-221 t-cases were never quiet.

[X Baldwin Motion]

Thanks, I found the link right after I posted. So the T221 makes that jet sound normally? It starts whining at 40 and close to 50 I need ear protection.

[begrab63]

Originally Posted by Olive1970

Wanted to bring up this subject again...my truck SPID is a factory TH350 trans with a 307 engine. Likely rear gear ratio? It seems that most of the 350 engines were 3.08 gear ratio with automatic, didn't know if it would be different on a 307 engine?

Thanks!

I have a 71 C-10 with a 307ci and the rear gear is 3:08...
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[TwoFiftyShifter]

I always thought 3.08 and the granny 4 speed was a sweet combo. No need for overdrive and can still pull a house in first. Just watch the gap between gears!

[SS Tim]

Suggested reading and in hand resources.

[X Baldwin Motion]

Thanks, that's great I wish I had them. Unable to download the manual onto my phone. Just need to see diagram or know where fill is for cardan joints.

[SS Tim]

Here...