1966 GMC 305 V6 Service

[Rufton]

Originally Posted by TommyDuncan

I know it's kinda early but I am really curious what kind of mileage you are getting.
Are they really as bad as they say?
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I'm very curious about the mileage also. I log mileage every fill. I put smaller main jets in worn out 305E last year and improved hwy mileage from 10 mpg to 12 mpg. The compression was so low and oil consumption so high I was surprised it didn't foul plugs. I hope the fresh 305E will do better. My gear oil in rear and trans may be too heavy for mpg; I'm thinking of switching to lighter gear oil.
I expect initial readings to be low because not fully broken in.

Guess I should road trip to get mpg data faster