I have a 1972 F100 302 that is stock, save for the dual exhaust, pertronix and accel super stock coil. I am looking to improve performance and gas milage, but have a limited budget. I was thinking of getting a 4 barrel and intake (currently a 2bbl @ 273 CFM), a cam, or a good set of used heads, and maybe some port work. Any suggestions are welcome.

 

well, a 4-barrel carb isn't exactly the way to better gas mileage. They eat more gas than your 2-barrel. The heads and port work will suck more air; more air = more hp. But then you run into technical issues like: is the 2-barrel carb and intake allowing enough air in for the new heads and porting? the answer is: no.

A 2-barrel with a 2-barrel intake manifold is childsplay for bigger heads and port work. Porting and heads have a far greater capacity for air intake than a 2-barrel can ever give.

So, full circle answer: if you want to port and go with bigger heads, you will have to go to a 4-barrel carb & intake manifold. Something in the 600-cfm, 625cfm, or 650cfm would work nicely.

Heads? the 2.02's may require additional lower end engine work. I went with the 1.90/1.60 Aluminum GT-40 turbo swirl heads from Ford Racing with a CompCam 268H series cam/lifter kit and Ford Racing 1.7 full roller rockers. The 1.7's will up the cam from a .456 to a .486 duration, which will increase torque. the 1.6's are close to stock, so I opted for extra "umph".

The overall answer: you likely WON'T increase gas mileage while trying to increase hp or torque... it usually doesn't work that way.
Sorry.

Good luck, and if I can help further... please don't hesitate.
Daryl

 

More...
I just noticed that you have a '72 302 with 300K on it. Before you stuff heads on it, you may want to have it compression checked and gone over for seals, head gaskets, etc. Also check clearances, springs, valves, bearings, etc.

Other mod's that would add to performance would be ignition and headers. Headers with dual exhaust would likely be a welcome relief to an older engine with a lot of miles on it. Another option is to bench build a newer 302 and just swap it out for the '72 302 with 300K on it. You can't expect to get a whole lot more use out of that one, can you? By the time you go thru the old motor, have it reworked then built up to the new performance spec's you want, it may be the same or equal money to build a new one... plus you'd have the confidence of having a motor with fewer laps on it than 300K.

If you do stay with the 300K motor, headers with dual exhaust and an upgraded ignition/wires would be nice additions.

Again,
Daryl

 

Ill be in touch, Daryl. I understood it that since the primaries on a 4bbl were smaller, my MPG would increase. Oh well, i have a lead foot, so i should have known better. The motor is in top shape, and I have confidence in my bottom end. I am on a limited budget anyhow. The valve seals are gone, but other than that, there are no leaks, and I have 55lbs of oil pressure cold just off idle, and 35-40 cruising with the motor warmed up.