78 cruise control question

[Honky Kong jr]

The thing im finding is that for a stock th350 theres like 5 different speedo and main gear sets and idk whats factory or correct for my truck. I hear theyre cheap and easy but ive never had to do them

You have bigger tires it will never be 100% correct but matching the speedo gears will get you semi close.

 

[78C10BigTen]

You have bigger tires it will never be 100% correct but matching the speedo gears will get you semi close.

Idk whats factory but i got it with 31x10.50x15 and thats what ive kept on it

 

[Honky Kong jr]

Idk whats factory but i got it with 31x10.50x15 and thats what ive kept on it

They are Probably a bit taller then stock.

 

[1987 GMC Jimmy]

Do you still have the sticker on the door? That should say what it came with.

 

[78C10BigTen]

Do you still have the sticker on the door? That should say what it came with.

I dont thik mine has a door sticker. Spid may say...

 

[Honky Kong jr]

I dont thik mine has a door sticker. Spid may say...

Go look

 

[74 Shortbed]

Turbo 350

Ok, you just have the bullet type housing, you have the wrong combination of gears. This will help getting the right combo.

https://transmissioncenter.net/product-category/gm/th-350/

http://www.laspeedometergear.com/

 

[78C10BigTen]

Go look

Heres what it says on the spid... whats that mean lol

You must be registered for see images attach

 

[Snoots]

They are Probably a bit taller then stock.

Stock size for a '73 1/2 ton is that size.

 

[Honky Kong jr]

Stock size for a '73 1/2 ton is that size.

Oh ok I learned something new.

 

[Honky Kong jr]

Heres what it says on the spid... whats that mean lol

You must be registered for see images attach

You must be registered for see images attach

 

[78C10BigTen]

You must be registered for see images attach

So my truck factory should be a 235/15 not a 31/10.5

 

[Honky Kong jr]

So my truck factory should be a 235/15 not a 31/10.5

According to your build sheet and that chart.

 

[78C10BigTen]

According to your build sheet and that chart.

Im not sure what the size diff is betwen the 2

 

[1987 GMC Jimmy]

2” diameter