67 base rear end ratio

[hotrodder]

what is the most common gear ratio used on a 67 base truck with 6cyl/ three speed? no options except vinyl seat and deluxe heater. now that is pretty basic!!

[Tinkermc]

411

[michael bustamante]

Hey youre sescribing my truck. No frills! If someone can tell me how to count whhel rotations/ input shadt rotations ill do it in the morning and tell you
I hope its not 3:08

[NC67Chev]

I would've thrown out 3.73, but I'm far from an expert. Here's a thread with rear end codes:

http://67-72chevytrucks.com/vboard/s...d.php?t=578793

[67ChevyRedneck]

The majority of 3 speed trucks had the 3.73. The majority of automatics got the 3.08.

[Sklptrljay]

Pretty sure it's 3.73.

[nascarguy320]

My 68 is a six 3 on the tree and 3.73 gears..

[70blackfish]

my 69 6 manual trans had 3.73

[Keith Seymore]

Base axle, according to GM, is 3.73.

K

http://www.gmheritagecenter.com/docs...olet-Truck.pdf

[hotrodder]

Thanks to everyone for the info. The fellow I bought it from put a 5speed from a s-10 in the truck and it seems to be really low geared. I drive it everyday and I don't want to wind it's brains out!

[HSRACER]

It shouldn't rev very high with a 5 speed!

[Fitz]

Originally Posted by michael bustamante

Hey youre sescribing my truck. No frills! If someone can tell me how to count whhel rotations/ input shadt rotations ill do it in the morning and tell you
I hope its not 3:08

It wasn't. The sixes came with a 3.73. Small block 8's had the 3.08

[Alex V.]

If you're used to listening to modern trucks with 3.55's or 3.73's with OD transmissions and 31" tires - i.e., a stock 90's Silverado 1500 Z-71 - it'll sound like it's screaming, but GM designed the small blocks of the 60's, 70's, and even through the mid 80's to thrive at 2,500-3,000 RPM. Yes, they run faster than modern vehicles, but that doesn't necessarily hurt longevity (nor fuel economy, as much as some will say) and gives you more of the engine's power without downshifting. Would I take my '85 C3500 (454/TH400, 4.10's) or '67 Suburban (350/NP435 4-speed/3.73's) and flog them down the interstate at 75 MPH for hours? No, but I'm not afraid of sustaining 65 and laying into them when I want to put a Honda in its place. GM trucks' reputation, from the sport utility boom of the 60's through the "Like a Rock" commercials in the 80's, didn't come from owners that kept their trucks under 60 MPH.

[jocko]

Originally Posted by HSRACER

It shouldn't rev very high with a 5 speed!

Assume he's referring to lower gears, not od. 1st gear in an s10 t5 is pretty deep - some were over 4:1 ratio - to allow the little 4 cyl get the s10 moving. When adding more gears to the trans, the sweet spot for rear end ratio drivability narrows significantly. 3.42-3.73 range are the best choices for an od trans to keep highway rpm from getting too low while also not making 1st gear final ratio so deep you have to shift about 10 ft after you leave a dead stop.