Lt_Murphy

i have a 77 F150 with a 400 V8 and a four speed transmission. the problem that i am having is that the gearing is so low that i have to start i 2nd gear, and have trouble hitting 50 in fourth. how can i get better performance (more speed ) without sacraficeing my ability to pull bushes out by their roots?

outback_ute

Do you use first gear, and how much of it? Also do you know what diff ratio/s you have now? What size tyres are you running? You have two basic options, raise your gearing or fit an overdrive gearbox.

If you don’t want to lose your current low ratio 1st gear, you could change to a 5 or 6 speed gearbox (eg T56 or Tremec).

If you think you could stand to raise first gear, you could change the diff ratios or fit taller tyres.

Lt_Murphy

if i use first gear to start, i have to shift gears before i hit 5 mph. my tires are 26-30 inches, with the bigger two on the back.
as for the gear ratios, i dont know what they are or how to find out. i would like to keep as much power as possible, but i think i have more than i need, so how hard is changing the gear ratio, and how hard is a new tranny

LunaticSVT

On that year and engine that first gear is called a granny gear. My friend has the same model and he too has to start in 2nd. He complains all the time about it. The problem you state about hitting 50 in 4th...can you not get above 50 in fourth? I am a bit confused on that one.

OlSkool

Another problem LT_Murphy, your actually going slower than ur speedo says, since youve got huge tires on that thing.

outback_ute

Wouldn't that be faster? The speedo reads wheel/tailshaft rpm but taller tires travel further for each revolution.

Lt_Murphy

if i try to go over 50, the truck starts making so much noise that i cant hear anything else. i think most of it is from the tires, but im not sure. the biggest problem with it though is how long it takes me to go from around 30 to above 40.

regarding the speedometer, i had a friend pace me and ran some trig so i have a good idea of what speeds i am actually going

LunaticSVT

I would get your speedometer calibrated.

That is the easiest thing to do and should not cost too much.

Changing the ratios is not that hard really....if you have a general idea of what you are doing and how to throw a wrench.

Lt_Murphy

i dont know how to change ratios, but i do know how to throw a wrench. if someone could point me to decent instructions, i could most likely do it.

OlSkool

if your talking about ring and pinion ratio, dude if u dont know, just find someone who does and pay them to do it, and yes, you are going slower than you think with bigger wheels. that why i laugh at these puds when they put 18 inch wheels on their honda, thats why i rock 15's