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Ziegelsteinfaust · 10-19-2019, 08:28 PM

Depending on the build of my engine, and carb size+style. I like my engine to spin about 2200-2500 rpm at desired drive rpm.

The slightly higher rpm works very good if your running let's say a 750cfm Holley.

If you want to run right at 2000 rpm or lower. Only a small Holley or Q-jet is going to have enough air flow for proper atomization of the fuel. Even then it never really got better fuel economy then before I regeared. Or my higher geared trucks didn't do worse then comparable friends trucks.

There was a thread on this site where a guy put a 5 speed behind his truck, and his mileage stayed the same or dropped slightly. I forget the exact details.

Depending on how your cam is. You need to be on the start of the torque curve for idealistic mpg. Tonight I am going to get a tunnel ram hopefully, and that means 3000 rpm for best mpg.

10-19-2019, 08:28 PM	#8
Ziegelsteinfaust Registered User Join Date: Dec 2012 Location: Temple City Posts: 3,565	Re: Gearing for 1970 C10 Depending on the build of my engine, and carb size+style. I like my engine to spin about 2200-2500 rpm at desired drive rpm. The slightly higher rpm works very good if your running let's say a 750cfm Holley. If you want to run right at 2000 rpm or lower. Only a small Holley or Q-jet is going to have enough air flow for proper atomization of the fuel. Even then it never really got better fuel economy then before I regeared. Or my higher geared trucks didn't do worse then comparable friends trucks. There was a thread on this site where a guy put a 5 speed behind his truck, and his mileage stayed the same or dropped slightly. I forget the exact details. Depending on how your cam is. You need to be on the start of the torque curve for idealistic mpg. Tonight I am going to get a tunnel ram hopefully, and that means 3000 rpm for best mpg.