Can anyone suggest the proper gear ratio?

I am running a 351 cleveland with a C-6 auto and the stock 9" rear. I want my truck to be more highway friendly. I am not sure of the present ratio, will probably crawl undrneath this weekend and see what it is.

 

Those Clevelands like to turn anyway, but for comfortable cruising on the interstate with no overdrive, I'd keep it between a 3.00 and a 3.50. That's kind of a tight range. Really need to know what kind of a cam is in it and roughly what the truck weighs to give you much more than that. If your cam is stock or a high torque grind, you could get away with a numerically lower set (maybe down to around a 2.75 or so), but if the engine can't handle it, the power and mileage are going to start to suffer.

 

I have a friend with the same setup in a 56' his 3.25 gear ratio works out good. I believe a 3.00 would be too light and a 3.50 may be hard on the gas mileage

 

Which 351C do you have? A 2 barrel or 4 barrel version? The 4 barrel needs to run at least 2500 rpm's or it will load up and foul the plugs.
I have a 2 barrel 351C in my 56. When it had the C6 (it has an AOD now), I had 3.50 gears in it. It ran about 3200 rpms at 70 mph. I ran it like that for years. 3.25 gears probably would have been better.

 

I am pretty sure it is the stock cam. I am running a two barrel carb. I am not a "Ricky racer", but surely don't want to lose to much power. When those little toyotas pull up next to me, sometimes I like to show them what American muscle is all about.

 

Thanks for the replies. I am not running a tach right now, so am not sure where I am at as far as RPM's. Plus, I need to install that new Speedo cable thats been under the seat for a month!