Slick 60's

Hello all,

I am brand new to this forum. I recently purchased this truck http://cgi.ebay.com/ebaymotors/ws/eBayI ... Action:MPS

The truck has a 390 bored .30 over and a 3 speed tranny. The seller said that the truck runs 4k RPM @ 70 MPH and gets about 10'ish MPG.

I would like to squeeze more miles per gallon (who wouldn't) while retaining as much of the "fun factor" associated with the BB engine. My plan is to install a 4 speed and a different running gear to drop the RPMS @ highway speed.

Can anyone offer any suggestions as to the best tranny/gear combo for this truck?

I am also toying with the idea of putting nitrous on the track just for fun.

good looking truck. do you know the rear end gear ratio? 4k sounds kind of high unless it's got 4:10's or something. taller gears will help, but the fun factor will go down too. mine is a 68 with the 360 3sp with 3:xx gears and doesn't do much better on mpgs.
you might check out "fordification.com" for more info specific to the 67/72 trucks.

It will be a couple of weeks before the truck makes the trip from MD to SD. I will find out the specs then.

I am thinking the 390 has enough punch to allow for a taller gear, but if it is not going to gain and relief at the pump then what is the point really?

Might just have to get a 2nd job to pay for gas.

I have a 352 bored with a small cam and 3.00 gears in the rear, and at 70 Im at about 2800 rpm. Still good off the line and Im pretty happy with it. As far as the gas milage the best thing to do is act like you dont know. This hobby is getting more and more expensive.

That definitely sounds like it's got 4:10's in it, or steeper. Anything from 3:00 to 3:50 rear gears would be a big improvement in the mileage department...and make the engine last longer too.
Looks like the guy did a nice job fixing 'er up, including things like disc brakes & sway bars.
I wonder what the blue thing is inside the spring...a spring helper of some type?

Yeah, I was thinking 3.50 would help drop the revs and still keep enough punch for the feel of all that torque hitting the ground.

That "blue thing" is an airbag. It has air adjustable front suspension to eliminate the front corner dip that often happens in corners.

I think the guy did a great job on the truck and I feel I got it for a fair price. Just can't wait till it gets here.

fr0gman wrote: That "blue thing" is an airbag. It has air adjustable front suspension to eliminate the front corner dip that often happens in corners.

Oh, that makes sense. I guess you can tell how many air bag installs I've done...

Good looking truck.

Lonnie

Welcome!

You will find a lot more info on FORDification.com , but we can help here too. Most of us have Bumps and Slicks.

I hate to be the one to tell you but FEs (352/360/390) will get 15mpg at best. Most can get 12mpg with a little work.

Good looking truck.

my 63 sb/flareside has a 390, and 2.75 rear installed, still spritely, albeit not as quick off the line as my 3.89.

I leaned out the carter 625 with the leanest charted jets in the edelbrock manual, and am getting 9-12 mpgs... (9 coming from Tucson to Prescott, 12 going down the hill)

Spins maybe 3500 (not sure) at 70....

I'm thinking of seeing if gear vendors makes an adapter to fit a car toploader, but you need to get the RPM down below 2000 before you can see any real difference, I think. Which means that you would still have to run about 3.00 gears to get there, If my math is right. There are differences in the four speed car tranies, not sure if the big spline might have lower gear ratio in first.

Rich