The Stovebolt Site Forums The Shop Area Engine Shop i cant go "55"!

Looking to see if anyone can suggest the cheapest / easiest way to convert the rear end in my 58 so I can get up to the speed limit. Dont know what it is geared at, but I cannot go 55 on the highway. Even at 45 the engine sounds like it is going to explode! Thanks for any help you can supply. The truck si a 235 3 speed. Everything is stock.

Do you have a 1/2 or 3/4 ton model? Half ton would be maybe 3.90's; while the 3/4 will have 4.57's . Small blocks like it, sixes don't.
Check your rear axle ratio and see what you have first, then we can point you in the right direction .

Try this:
"Jack up one tire if you have an open diff, or both tires if you have a working posi or locking differential. Rotate the tire one full revolution for posis and lockers and 2 full revolutions for open diffs. Carefully count the number of full
revolutions the driveshaft makes. This is your gear ratio. In other words, if the drive shaft turns 3 & 3/4 turns, you probably have a 3.73 gear ratio. Turning the tire for twice the number of full revolutions and dividing the drive shaft revolutions by two will give you a more accurate reading." (quoted from West Coast Differentials)

A Chevy 6 should spin fast enough to get you to 55 or beyond, even with low gears. (Unless you've put super-small tires on.)

55 MPH with decent truck tires should require about 2600-2700 RPM, even with a 4.57 axle. Well within Stovebolt territory.

My 235 was way noisy at RPM; I finally discovered the old fan blade was unbalanced and the water pump bearing was bad. Look at the little stuff first, you may not need to re-gear.

Cheers!
George

Hey '58 stepside,

I also have a '58 stepside (3100) 235 c.i.d., 3 spd, stock 3:90.1 rear end. I can cruise at 55 - 60 easily all day long.

What size tires are you running? What kind of noises is your engine making? Are your valves set correctly? Be sure to check for other things like bad bearings in a gen (or alternator) they can make a heck of a racket too. Let us know!

Thanks for all the help so far. The engine is strong and the only sound it makes at highway speeds is a high pitched whine. In my opinion the rear end must be geared for farm work and not highway speeds. i saw a kit on the chevyduty page that would remedy this problem, but ti states it needs to be installed by a pro. does anyone know is there an alternate rear end I could swap to to allow me to cruise at 60 or so? Or do I need to get the kit installed from chevy duty to ge tthere. I have not tried the jack it up and spin the tires trick yet, but I am replacing the rims that are on there for stock ones and I will try that then just to see exactly what rear end it is.