So I'm new here, this is my first time posting (besides a little "hi, I'm new" post). Here's my "problem"...

As it is, the truck I'm driving has I think a 4:10 gear ratio (very short gears). That wouldn't be much of a problem but for the fact that my transmission has only 3 speeds, which means I top out at around 65 mph because the gears are so short. To make the truck act more like a newer vehicle as far as the top speed is concerned, should I switch out the rear end for something with longer gears, or would I be better off swapping the transmission for something with more gears? There's a lot of things I've taken into consideration for both of them, and either way it's not something that's going to be happening in the near future.

Long story short: short gears + not a lot of them = low top speed?

Also, if you need any more specs and information, I'll gladly give up what I can.

 

Specs of vehicle?

 

Is it a chevy?
TH350 trans?

As much details as you can think of is more helpful..

But theres only 4 things that are goin to limit you.. Engine RPM, TRans Ratio, Rear axle Ratio, Tire Height.
Th350, TH400, 4L60E, 4L80E all have 1:1 3rd gear so goin to a 4 speed isnt goin to help.

So the easiest thing to do is Gears or taller tires.

 

I've been over 120 in mine with 4.56 gears.

 

you shouldn't be out of gear at 65mph even w/ 4.10's. i run 3.42 w/ th400 not too bad cruising.

 

With 3.08 I've reached the point where aerodynamics overpowers my horsepower and tire rating.

 

it's a 72 c10 with a pretty much stock 454. i'm pretty sure the trans is a th350. I don't know the exact gear ratio, but considering the shortness of the gears I'm left with the assumption that they're probably 4.10's, or something close. First gear hits about 15, second hits about 40, and I never really let it get past 60 or so, except for a few times. Since the other two gears are so short I'm afraid I'll end up blowing it up if I take it over 70.. Couldn't tell you the HP or TQ rating as I've never had the thing on a dyno. If I had to guess I'd probably say 270-310 HP and 380-420 ft/lb TQ.

 

Ive heard of older trucks having extremely short gears. You might have 4.56 or 4.88 or higher with 26-28 inch tire or smaller. Also that big block might not rev past 5k rpm. I might be completly wrong.

 

Get a tach for cheap and a gps, or use a smart phone. Get a real rpm and mph reading. You could run 5.38 gears with 28" tires and not be topping out even a peanut port shrimp dick cammed big block at 70 mph. That would be about 4300 rpm. Also, with a bad modulator/wrong governer springs and weights/poorly adjusted kick down cable, it will shift way too soon like you described. Check to see that you're getting full carb opening with the pedal floored. If it runs out of power at a low rpm, your carb secondaries may not be opening. Check the timing too.

 

LMFAO, that's great. Probably sounds like it's about to pop at 65mph, though.