selecting rear end gears

[350supercharged]

would anyone know what rear end gears are in a 58 chevy apache 3100 longbed truck? Would those gears work with a supercharged 350(550hp) engine with th400 or th350 transmission? It will be driven mostly on the street/road and occationaly strip. If not what would you recommend?

[MagicRat]

Trucks back then had a wide variety of optional gear ratios... you will have to get underneath and have a look... lift the rear end and spin the rear wheels together, and count the number of times the driveshaft turns.

I hope you will use the 400 trans in this combination, most th350's will be turned into Rice Krispies with that kind of power.

As for the ratio, are you putting tubs and a narrowed rear end in the back, so you can get wide, sticky tires?

If you are going to keep the stock wheelwells and streetable tires, a 3:1 rear end is about as short as you can go. Pick up trucks tend to lack traction at the best of times, so you will spin the rear tires in first gear, regardless of the rear end ratio. So you may as well have a reasonably tall rear, so highway cruising will be comfortable.

[oldblu65]

A 1958 Chevy pickup would have gears in the 3:73 to 4:10 range . These ratios would be good for performance but the stock rear end would never stand up to the abuse that your proposed engine power would produce . The automatic transmission might help some of the shock to the antique rear end but it would quickly crumble under the power . You definitely need a stronger rear end !

[MagicRat]

Originally Posted by oldblu65

A 1958 Chevy pickup would have gears in the 3:73 to 4:10 range . These ratios would be good for performance but the stock rear end would never stand up to the abuse that your proposed engine power would produce . The automatic transmission might help some of the shock to the antique rear end but it would quickly crumble under the power . You definitely need a stronger rear end !

Oh yeah, forgot to mention that. As oldblue says, the stock rear is hopeless..... parts are rare and it's weak. An easy swap is to get the Ford 9-inch rear axle. Parts and gear ratios are easy to get, they are super strong, lighter than the GM axles, and were made in a variety of widths. You should easily be able to find one with the correct width. You may have to weld on new spring perches, but thats no big deal.

Aftermarket new Ford-type rears are available with any ratio you want, if you do not want to be bothered with used stuff.

[350supercharged]

im not sure. i would like to get a little wider tires than what are on it(235/75R15) so it would look as good as the trucks on the internet, but not too wide that i would have to modify the fenders. What would you recomend for a reasonable wide tire that would look good and go with being driven alot on the road? Thanks.

[350supercharged]

i found this th350 trans. What do you think? TH-350 Chevy Street & Strip w/6" Tail Housing [35001] $844.00

Rated to 650 HP Retains automatic upshifts and O.E.M. shift patterns O.E.M. input and output shafts Firm positive shift feel Modified pistons for clutch clearance Modified high volume pump ALTO clutches and steels Heavy duty intermediate sprag race New bushings
TS has the th400, but they start around $1200 AND are rated for 850hp, i think that the TS th400's are rated to high for what ill be using it for, i think getting the TS trany th400 will be a waste of money since i will not have 850hp. Do you know where i could go for a th400 at a good price, or could i just get one and have someone just rebuild it to handle 550 hp? What do you think. Thanks.

[350supercharged]

im just throughing this out there since im just a newbie, but could i just keep the stock rear end housing and just put the 9 inch differential and axles into the stock housing? Thanks

[MagicRat]

For the transmission, go for the th 400.
it's your best choice.

High-performance th 350's are built for 2 reasons.

1. For some performance cars which already have a th 350, so fitment is easier than swapping in a 400.

2. For drag racers who want to squeeze every last tenth of a second out of their track times.... even if they may eventually blow-up the transmission doing it. The th 400 transmission produces very slightly slower ET's than a 350, due to its heavier, more robust design. However, this is only relevant for people whose margin of victory is measured in 1/100 sec.

For everyone else, including you, the stronger th 400 is better. Also, realistically, $1200 is a reasonable price for a performance-built th 400. A regular, stock trans rebuild, with a new converter starts in the $800 range anyways, plus whatever you have to pay for buying a rebuildable core.

Also, don't pay muc attention to the 650 vs 850 hp ratings. They are not accurate. There are many other factors that affect transmission life, such as torque converter stall speed, rpm rate at which peak power is reached, how hard your car launches, rear tire set up, etc.

Finally, the Ford 9 inch center -section and axles require a matching Ford axle housing, so, they will not fit your stock rear.

[350supercharged]

OK Thanks a lot.

[kecarguy]

Hey,
im new to the chat and i am currently serving oversees. I am looking for a stong rear end to handle my 1988 chevy pickup. Currently pushing about 500hp. Want to keep the cost at a minumum what do you all recomend that i use. 10 bolt from an old camero or a ford 9 bolt.

Thanks carguy

[maxwedge]

Welcome to AF. Ford 9 is a stronger diff than the weak Camaro 10 bolt. BTW in the future start a new thread this is too old.