The Stovebolt Site Forums The Shop Area Engine Shop kill two birds with one stone...............I hope

so. here goes

my 62 is up for sale, but if it doesnt sell, i will be making some subtle changes. With this in mind, im trying to get my materials together so i can do this smoothly.


I have the stock 4spd (SM420) trans, and i'm thinking of swapping for a T5. I have heard the pros and cons of doing this, but i haven't heard alot of other alternatives without going automatic.
So what manual trans can i pull out of what truck and what year for mine? i have the 235 inline.


Second, i know the best way to get some mileage and top end speed improvement is to swap the gears in the rear end. I am probably wrong, but im under the impression that the 12 bolt has a 4.11 rear while the 10 has a 3.93 or something like that. I thought i had counted a 12 bolt rear on my 62, but after having ripped up the bed wood today(and doing it in daylight) i found i have a 10 bolt. does this mean that my gear ratio is lower?

HBM

I am assuming you have a 1/2 ton. The rear axle should be the same as a 54 to 62. That is a round 10 bolt cover with 3.90 gears.

As for the trans beyond what you already know, there is a later model 5 speed trans that was used in light duty trucks. It was used in GM and Dodge. I have heard, more so in the Dodge than the GM trucks. I think it is refered to as an NV something. Not much help I know.

Here is a link to a reference about the NV 5 sp. There are more, just do a search for them.

First bit of free advice (worth what you pay for it): Jack up one rear wheel (chock the fronts), put it in neutral and mark the driveshaft on the side nearest the raised wheel (so you can see it while you spin the wheel). Mark the tire or use the valve stem to count revs. Spin the wheel 1 rev (slowly) and count how many times the shaft turns. Multiply that count by 2. That is your rear ratio. Maybe gears can be changed or maybe you can get a new axle... Or maybe it is just what you need.

Second: check out the tech tips. There are good write-ups on the T5 swap. Also do a search for T5 and read the threads.
The S10 box shifter fits better (closer to the front), but the World Class out of (some) V8 Camaros is stronger and has different ratios. You can build a hybrid from two boxes... Tailshaft and output shaft from the S10 on the Camaro box gives you the strong box with the forward stick.
You will need (at least) a new clutch disk to match the splines of the T5 input (11" Astro van comes up alot). The rest is installing... Trimming the bearing retainer, drilling out mounting holes to the right size, and maybe extending the splines a little for clutch play... Maybe fabbing up a trans mount.

That's a quick summary.... Do a little research and you should have no trouble.
Good luck

I have done the NV swap in earlier trucks. Let me say I would not reccomend the NV4500 in a 1/2 ton pickup behind a 235. The NV4500 is a BIG transmission. I wouldn't hesitate to reccomend it for a 3/4 or 1 ton truck, or a 1/2 ton that has a high powered motor. This swap is more expensive than other popular transmission swaps.

this is good stuff. gear ratios and such things are black magic to me. i could never understand them, but im beginning to.

So with the T5 swap, the 3.90 would be good? or should it too be swapped to something lower? i still want to be able to haul stuff in the back when i need it, but i dont want to overstress the trans.

Hey Hombre...
Get a list of ratios for the T5 (I don't have them handy, but they're around).

To find road speed from engine speed use the following formula:

(RPM x Tire Diameter(inches))
----------------------------- = MPH
336 x Rear Ratio x Trans Ratio

For example...

2500 RPM x 32 inch tires
------------------------------- = 8 mph at 2500 rpm
336 x 4.57 rear x 6.48 (1st gear)

From this you can figure out how fast you can go in each gear. It should tell you whether you can pull that boat up the mountain or go down the freeway without earplugs.

Good luck

highflyer, that is good math skills you have there. i will look for the gear ratios

oh, i remember seeing a site that decodes the trans number off the trans case and tells you what the ratios are. anyone have that link?

The other Transmission option would be to put a 3 speed w/OD in it like this one: Transmission I put one similair to this in my 58' and I can cruise 65 mph with no problem and still have th 3.90 so I can pull stuff.

Hey Hombe,
Do like Flyer says, search and all you need is within the archives for the swap.
This is how I got mine done.
Go to the Inliners page (http://www.inliners.org/), proceed to Tech Tips, & T5 Tranny Page. Info like this...model number 1352-042, year 1984 - 85, vehical S10, motor size 2.8 V6, Gear ratios for 1st through 5th - 4.03, 2.37, 1.49, 1.00, 0.76. Printit off - this will be your shopping list later.
Next, go to http://www.onlineconversion.com/bigger_tires.htm compliments Stovebolt, Tech Tips, Transmission Drive line, first bullet.
Get you tire height, rear end ratio (3.9 or 4.10), and desired speed. Someone on here can give you ideal RPM for the 235's optimum torque and HP number. Go to town, then go to the junk yard.
My case I went for 70 mph as my ideal cruising speed.
Hope this gets you started,
Brett

Hombre... Not my math skills. Actually saw this formula the other night on the Bolt. Copied it down to check my 3/4T. Paper was beside the computer. :-)

Thanks, though.

i love you guys!

i guess i did come to the right place for answers!