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*Sharps40* · 09-25-2013, 09:18 PM

I'm runnin a 65 SBSS. 1971 Olds Rocket 250 I6. Currently running the peanut 3 speed and 3.73 rear. With the weber 2 barrel and the HEI ignition I pull an honest 18.4 mpg combined hwy/city every tank. Ocassionally 19.5 to almost 20 on the interstate staying at or below 65 mph.

Switching to a 5 speed this winter, expecting to see an additional 2 to 5 mpg.

308 might be a bit much for a six....pretty slow start but prolly great on highway...your final drive should still be 1 to 1 just like the peanut. (Mr. Langdon does not recommend less than about 3.50 rear gear with an overdrive manual gear box...so I'm stickin with my 3.73 out back.)

09-25-2013, 09:18 PM	#2
Sharps40 Account Suspended Join Date: Oct 2012 Location: here Posts: 2,408	Re: straight six question I'm runnin a 65 SBSS. 1971 Olds Rocket 250 I6. Currently running the peanut 3 speed and 3.73 rear. With the weber 2 barrel and the HEI ignition I pull an honest 18.4 mpg combined hwy/city every tank. Ocassionally 19.5 to almost 20 on the interstate staying at or below 65 mph. Switching to a 5 speed this winter, expecting to see an additional 2 to 5 mpg. 308 might be a bit much for a six....pretty slow start but prolly great on highway...your final drive should still be 1 to 1 just like the peanut. (Mr. Langdon does not recommend less than about 3.50 rear gear with an overdrive manual gear box...so I'm stickin with my 3.73 out back.)