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68gmsee · 09-17-2007, 08:50 AM

I agree with Brad. I, too, would go with the 305. It's more versatile in the carb selections and parts for upgrading are readily available.

With the engine conditon being at it's maximum efficiency, size does not determine mpg, unless, of course, you are in the big block category. A six cylinder has to work harder to get the truck going than a v8 so it may not buy you much.

A lot of other factors are involved here. As already mentioned, rear end ratios, driving conditions (city or rural), carb efficiency, tires, weight of vehicle, etc...

And as mentioned also, a single and 2 barrel carb are not the most economical. A well tuned quadrajet with the small primaries can give you as good or maybe even better mpg's than a 2 barrel. Plus you have the option of the additonal power of the secondaries when needed.

09-17-2007, 08:50 AM	#11
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: 305 v8 or 250 I6 for better mpg I agree with Brad. I, too, would go with the 305. It's more versatile in the carb selections and parts for upgrading are readily available. With the engine conditon being at it's maximum efficiency, size does not determine mpg, unless, of course, you are in the big block category. A six cylinder has to work harder to get the truck going than a v8 so it may not buy you much. A lot of other factors are involved here. As already mentioned, rear end ratios, driving conditions (city or rural), carb efficiency, tires, weight of vehicle, etc... And as mentioned also, a single and 2 barrel carb are not the most economical. A well tuned quadrajet with the small primaries can give you as good or maybe even better mpg's than a 2 barrel. Plus you have the option of the additonal power of the secondaries when needed.