Transmission Upgrade?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

JBswth

Full Access Member
Joined
Jan 24, 2022
Posts
148
Reaction score
115
Location
Vallejo, California
First Name
James
Truck Year
1973
Truck Model
C25
Engine Size
292 cubic inches
Talking about a 70s - 80s gasser Squarebody. A diesel will always use less fuel. And by Japanese-like mileage I am talking about 30 or more MPG in a Squarebody. Can't be done with the stock gas engine.

J. B.
 

JBswth

Full Access Member
Joined
Jan 24, 2022
Posts
148
Reaction score
115
Location
Vallejo, California
First Name
James
Truck Year
1973
Truck Model
C25
Engine Size
292 cubic inches
That's pretty surprising, as you would think that the bed would act like a scoop and catch the air.

J.B.
 

dragstews

Full Access Member
Joined
Mar 27, 2024
Posts
63
Reaction score
113
Location
Belleview Florida US of A
First Name
Jesse
Truck Year
Body 1954, frame 1975
Truck Model
R-100
Engine Size
406 ci SBC
You Guys just about talked me into pulling the mouse motor (406 ci) and go to a rat motor ...

Then again I have this 12 valve sitting right close ..

You must be registered for see images attach


You must be registered for see images attach


Need to do sumthin with it .. ??
 

AaronW

Full Access Member
Joined
Mar 24, 2021
Posts
184
Reaction score
177
Location
MT
First Name
Aaron
Truck Year
89
Truck Model
V3500
Engine Size
454
I remember Mythbusters did this on two different episodes back in the day because people didn't believe the results the first time. Driving with an open tailgate gave the worst mileage, and driving with a closed tailgate gave the same mileage as having a bed cover. The open bed with a closed tailgate creates a vortex that helps air passing over the cab continue on unimpeded. Oddly enough, they got the best mileage with a net style tailgate.
I've got a flat bed, in any case.
 

Forum statistics

Threads
42,146
Posts
910,115
Members
33,643
Latest member
Scandia
Top