Educate me on a 12 bolt in a 78 K 10?

73c20jim

Supporting Member
Supporting Member
Joined
Jun 11, 2018
Posts
2,271
Reaction score
2,885
Location
Tombstone, AZ
First Name
Jim
Truck Year
1973, 1973
Truck Model
C20 2WD Custom Deluxe. C10 2WD Base Model
Engine Size
350 CID 195/260 HP Goodwrench crate, 400 CID 2bbl
Just as an aside about torque. How does the change in ratio affect torque, if you can chassis dyno the same motor with different ratios and get the same horsepower.
 

73c20jim

Supporting Member
Supporting Member
Joined
Jun 11, 2018
Posts
2,271
Reaction score
2,885
Location
Tombstone, AZ
First Name
Jim
Truck Year
1973, 1973
Truck Model
C20 2WD Custom Deluxe. C10 2WD Base Model
Engine Size
350 CID 195/260 HP Goodwrench crate, 400 CID 2bbl
And horsepower is a calculated number from torque and RPM,
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
2,938
Reaction score
2,889
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
And horsepower is a calculated number from torque and RPM,
Horsepower is a measurement of torque applied over a period of time. When you change ratios, you are increasing torque and decreasing RPM to get the same amount of power. It's math.... and science!
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
2,938
Reaction score
2,889
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Just as an aside about torque. How does the change in ratio affect torque, if you can chassis dyno the same motor with different ratios and get the same horsepower.
This page has the math for determining wheel torque and wheel force based on transmission gear ratio, engine torque, and final drive ratio. If you aren't interested in the math, you can scroll through to the pictures and the graphs at the bottom that do a good job of visually describing what happens to applied torque and force at the tire based on gear ratio and differential ratios.

https://x-engineer.org/automotive-e...hicle-dynamics/calculate-wheel-torque-engine/
 

Vbb199

B-rate Hillbilly Customs
Joined
Jan 12, 2018
Posts
8,300
Reaction score
13,281
Location
Salisbury NC
First Name
Vince
Truck Year
89, 79
Truck Model
89 Suburban R1500, 79 C10
Engine Size
350, 502
To start with, the early Ford gear sets are bevel cut gears. These offer more resistance than the spiral-bevel gear set in the GM rears.

The 1/4 mile racers could see this on their dyno tests. They combated this by fitting GM gears to the the Ford differential carriers. (very costly) Later, aftermarket gear companies provided spiral-bevel gears to fit.

You must be registered for see images attach


^ spiral bevel gears

You must be registered for see images attach


This shows the difference well. The automotive gear sets are really spiral bevel hypoid. This means the pinion gear is set at an angle to the ring gear (driven gear). That allows the pinion to be mounted lower than center on the axle.

You must be registered for see images attach

^ Hypoid

The second disadvantage to the Ford 9" is weight. On an integral axle housing, the carrier side bearings are supported by the housing. The removable Ford carrier requires the heavy casing for the side bearing support.

The last item is cost to put the 9" in a GM chassis. However you chose to do it, it is custom. Fabricators working on their own vehicle, this may not be an issue.

To answer your other question, the Dana 44 is much like a 12 bolt GM in strength. Dana 60's are an upgrade for both.


I appreciate this information right here.

I was deciding between a 9", 10 bolt, or 12 bolt for my c10.

Sounds like a 12 bolt would be the better option

@Bextreme04 check it out ^^
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
7,764
Reaction score
4,374
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
I appreciate this information right here.

I was deciding between a 9", 10 bolt, or 12 bolt for my c10.

Sounds like a 12 bolt would be the better option

@Bextreme04 check it out ^^
Ford 8.8 inch, no takebacks, and no promises. if you give me a loaded 12 bolt. deal? deal :)
 

wanderinthru

Full Access Member
Joined
Jul 23, 2020
Posts
920
Reaction score
1,293
Location
Mid Point Route 66
First Name
Shakey
Truck Year
81, 70, 75, 84, 89
Truck Model
K 10, C 30, K 20
Engine Size
350
I appreciate this information right here.

I was deciding between a 9", 10 bolt, or 12 bolt for my c10.

Sounds like a 12 bolt would be the better option

@Bextreme04 check it out ^^
Been a minute, and I may be recalling wrong? Have it in my head @Turbo4whl was talking about a 12 bolt car. Personally I went with the 9 inch, mainly because I got one for a 100 bucks, and it and a 12 bolt car is the only ones I could find the lower (5.6 or lower, I got a 6.2) ratios for.
Good luck.
 

Forum statistics

Threads
35,828
Posts
755,055
Members
24,841
Latest member
KC_Stuart
Top