1953 Chevy Pickup Transmission Installation - Five-4-Six

I love a good high-revving engine just as much as the next guy. Sometimes, though, high revs aren't such a welcome "factory option," especially when you're buzzing a Chevy 235 in upward of 3,500 rpm, yet everyone else on the road is flying by you almost effortlessly! The easiest and cheapest fix is to tear into that closed rearend and swap the ring-and-pinion for a shorter set (Patrick's has a kit just for that). But you're still dealing with an antiquated manual transmission, and personally, while "gentle" shifting isn't so bad, non-synchro'd gears aren't high up on my list. Again, Patrick's has the answer with his Saginaw four-speed conversion for '47-54s. But you're still dealing with the torque tube, and personally, I was thinking more open-minded for my particular project.

Basically, I'd planned from the get-go to swap the closed driveline in my '53 3100 for a more modern, open setup, but in a manner that wouldn't deviate too much from the stock appearance. As you may have seen last month, the first part of that swap was handled with the addition of a Dana 44 six-lug rearend installed with a Walton Fabrication parallel leaf kit. The next step, upgrading the transmission, was a little more involved. While going the S-10 (V-6) route is obviously the most cost effective, there are a lot of variables to deal with...it's basically a matter of coordinating all the right components to allow the T-5 to work comfortably behind your straight-six. Even though I chose the high road, I'll briefly go over what it takes to make this happen.

First off, you just can't use any old T-5, as there are more than a few variations on the five-speed; but there really is just one version that will fully suit the needs of an average 216/235 straight-six. What you'll want to locate is one from an '83-88 2.8L V-6. Forward shifter location, a .73 overdrive, and a mechanical speedometer all make for the perfect transmission to put in an AD pickup, as long as the horsepower is relatively mild (under 300). For a beefier application, you'll need to source out a Camaro T-5 for its stronger gearset, but you'll still need an S-10 transmission body for the shifter location, or at the very least, the tailshaft section. From there, you'll need to locate the appropriate clutch package (reports tell of mating a mid-'80s Astro Van pressure plate with a '70 Vega disc, but that was not fully researched), as well as open up the trans-to-bellhousing mounting holes to 33/64. (Again, since this route was not chosen, the associated variables may go further, or there may even be an easier route...I opted to take the right in the fork and venture the high road, as it were.)

My high road involved one simple phone call--no junkyard scavenging, no part number cross-referencing, no headaches--just one call. The folks at Keisler Engineering have done all the hard work involved with mating Tremec five- and six-speeds behind early Chevy engines. And by hard work, I mean when you purchase a TKO-500 PerfectFit kit from Keisler (this one rated up to 550hp), you don't just get a brand-new transmission built to order, you also get: the choice of three shifter locations, clutch package (pressure plate, disc, and throwout bearing), speedometer cable, needle-bearing pilot bushing, rear mount, neutral safety switch, hardware, and, believe it or not, a complete driveshaft. Obviously, the last part of the package actually comes last, as you need to provide Keisler with the pertinent info for them to make up the appropriate driveshaft for your particular application. Now, the TKO package is definitely going to be the more expensive route than the first option mentioned, but when you sit back and think about it, you're getting everything absolutely brand-spanking-new, with a limited warranty to boot! No rebuilding this, resizing that, or anything of the sort; pretty much a plug 'n' play deal. So when you put it like that, $2,595 starts sounding more like a good deal, doesn't it?

Keisler's TKO version of the venerable Tremec five-speed is actually more than you could bargain for. Along with the shifter location option (forwardmost works for this application), the customized tailhousing and shift tower, as well as the Muncie/Borg-Warner T-10 input shaft and bolt pattern, make it the perfect fit they claim it to be--and it is. When used with the early truck bellhousing, the TKO bolts right up behind your straight-six. Furthermore, with a nice and low 3.27:1 first gear, you'll still enjoy quick acceleration from the start; with the .68:1 fifth, you'll be able to enjoy open-highway cruising without vibrating your fillings out! Combine these numbers with a midrange 3.55:1 ring-and-pinion, and you're now looking at 80 mph at 2,500 rpm as opposed to the 55 mph the truck was used to with a 1:1 final-drive. You read that right--the TKO also includes a 30-mph freeway cushion!

Now, there is one issue that permeates over from the S-10 route, and that involves the input shaft. Due to a slight variance in flywheel depths, a minor modification must be performed. While some will tell you to actually trim the T-5's pilot nose (the input splines are not deep enough), you can also fab up a 1/4-inch spacer to go between the stock bellhousing and the new transmission, which keeps the input from bottoming out against the crank (in time, ultimately wiping out the pilot bushing). More importantly, it keeps you from having to mess with a hardened-steel component of your new tranny, not to mention voiding the warranty. Fortunately, the input shaft collar is about 3/8-inch thick, so it will still register in the bellhousing, which means you won't be relying on the mounting bolts for center accuracy. (Also, you'll notice in the photos that Keisler requires you to do a "runout" check on the bellhousing, which they use to verify a warranty.)

The timing was just right for this swap in my truck, as the weary old four-speed had definitely seen better days. On top of that, the clutch was all but burnt up, and the clutch fork down to its last thread of adjustment. More importantly, with the torque-tube rear long gone, there wasn't any real reason to keep the granny-geared tranny anyway! Suffice it to say, the Keisler TKO was and is a welcome addition to the project, no matter which way you look at it.