Well, I have personally got 21 mpg (highway) in my A code 289 4V 4-sp fastback, so I don't know what you did to get only 20. My 66 200/C4 convertible got 25 mpg on the highway. I had a 66 200/3sp, but never checked the mileage.

 

I never checked mileage on the 67. I wonder what it will get now with the Cleveland in it and 3.00 gears. One thing is for sure though, it wont use much gasoline and if I can achieve it, it wont burn anymore gasoline as long as I own it. I should build an AOD for it, that would make a fun cruiser.

Back to the O.P. its better to get a V8 car, but you can still do the upgrades, if you shop around a bit it wont be that bad. No need for a 9" rear, an 8" will do fine. Some Granada spindles will give you disc brakes and five lugs, if you can find Granada spindles. A radiator is a good upgrade anyway and its always advisable to add torque boxes to the side that doesnt have one. Do most of the work and hunting of parts yourself and its far cheaper than having a shop do the labor and legwork for you.

All is not lost, but why not rebuild the I6 and have a nice cruiser, then pick up another V8 car cheap? You can get Cougars real cheap and ALL of them from 67-74 had V8s in them. Its something different and still a classic Ford. Even though they are somewhat rare, they dont cost an arm and a leg to buy.

 

thanx guys, specialy 4 the confidence. I Can do it! (might take a few hundred posts)

 

True! Get the Factory Service Manual, and turn it into a nice cruiser. These cars are really easy to work on, when you have the right book and a little advice from time to time.

 

With my old setup (200 1bbl w/3 speed, 3.20 rear gears) I averaged 25 mpg.

 

The 302 in the 65 is not stock and its also has some fun with mild hot rodding and I get about 20 mpg average.

I find it hard to believe that any of those cars got that good. I have never seen a 289 Mustang with 3 speed or C4 get more than about 16 or so mpg. My Dad said that the 60 Falcon they had did not even get 20 mpg and it was a 170. He also said that hardly any car got more than 20 mpg. These are city highway mix or average.

I don't know what my 65 gets highway only. I haven't had the chance to figure it yet.

 

Thats the exact setup my car originally had. It never got more than about 20.

 

For the original poster. I agree with what was said earlier about it being rewarding to do an I6 to V8 conversion. I would say that it definitely was a rewarding project. I would do it again.

 

+1 on this statement.