[jcp123]

Well I think 15 is possible, but it'll take some serious work. Back in the very early days of my questing for gas mileage, I had a '92 Bronco (same bodystyle generation) with a stock 302 and automatic and averaged around 13,3 in mixed driving, 18+ on the highway. Yours has the advantage, I believe, of sequential fuel injection vs. batch fire on my older 302, and I think they had roller cams in the 351's by then which my 302 also didn't have. Plus you have have a mass air system versus my speed-density EFI, so you have three advantages right there if I'm right on the roller cams.

I am a little jealous, that was one of my favourite truck bodystyles with a crew cab and a 351...it's a nice combo. I had a chance to buy a similar truck with a 460 but I'm glad I passed on it. Also had the chance to buy a '95 Eddie Bauer F150 with a 300 straight six and 5-speed, I regret passing on it. 5-speed would be nice though the 5-speed Ford trucks that got EPA mileage ratings got lower mileage, so I don't know if the final drive gearing is less advantageous on the manuals.