Without even realizing it, we'd built a domestic ricer. Replete with a sweet stance, big wheels, gooey meats, and a cutting-edge suspension, our '65 Cutlass project car certainly looked the part of the quintessential g-Machine, but fell three gears and 300 hp short of being the real deal. With the help of the School of Automotive Machinists, we embarked upon addressing the power shortage last month by putting the finishing touches on a 514hp big-block. Now it's time to move on to the second act of Project Olds' powertrain shuffle by ripping out the miserable two-speed slush box for a complete five-speed swap kit from Hurst Driveline Conversions. This comprehensive setup includes every last nut and bolt necessary to install a Tremec TKO transmission into a GM A-body, and any monkey with a wrench should be able to knock out the install over a weekend.
We'll spare you with the details on how to pull a 330 small-block and a two-speed trans out of a '65 Cutlass, but suffice it to say that they both came out in one fell swoop, and we were glad to see them go. Upon measuring the dimensions of the small-block next to the big-block, Jarvis realized that both are very similar in size, so he decided to use small-block motor mounts to bolt the 461 in position.
Hurst Driveline Conversions specializes in turnkey five- and six-speed swap kits for a variety of GM and Mopar muscle cars. Enthusiasts can choose between either a Tremec TKO 500 or 600, or a T56. Since one overdrive ratio was plenty for Project Olds' intended use, we ordered up Hurst's Elite conversion kit with a TKO 600. Designed for cars originally equipped with an automatic transmission, the Elite kit includes a five- or a six-speed trans, a driveshaft, a speedometer cable, a trans mount, a pilot bearing, a bellhousing, a flywheel, a clutch, a tunnel patch, and a shifter and knob. For factory manual trans cars, Hurst offers its Deluxe kit, which scratches the bellhousing, flywheel, and clutch off the list. If that formula of top-to-bottom thoroughness sounds familiar, it's because Hurst Driveline Conversions has been around for a while, but has recently changed its name. The company's former handles include Classic Motorsports Group and Classic Chevy 5 Speed. Regardless of the moniker under which it operates, you'd be hard-pressed to piece together a Tremec trans swap for less money than it costs to order up a complete kit from Hurst. For those who already have a custom driveshaft and shift knob, one of Hurst's Basic conversion kits can be had starting at $2,195.
In what has become a monthly tradition during the steady progress of Project Olds, we once again turned to Performance Restorations(www.PerformanceRestorations.com) for assistance with the install. A hardened veteran builder of Pro Touring cars, Brent Jarvis has installed tons of five-speeds in his day. "At our shop, five-speed conversions and big brake swaps are the two most popular upgrades that we do. Installing a modern five-speed trans is one of the best mods you can make to modernize an older muscle car and make it much more fun to drive," he says. Since we're also dropping in a fresh 461ci big-block Olds along with the Tremec five-speed, we had to break this story down into two parts. We'll tackle the engine transplant and bolt the tranny into place this month, then finish buttoning up the clutch linkage, pedals, driveshaft, shifter, and interior next month. Then Project Olds will be ready to turn some laps!
In addition to everything Hurst includes in its comprehensive Elite kit, we ordered the optional SFI bellhousing, billet steel flywheel, and heavy-duty clutch. Hydraulic clutch linkages and pedal kits are available for some cars as well.
RATIOS GALORE
Trans
First
Second
Third
Fourth
Fifth
Sixth
TKO 500
3.27:1
1.98:1
1.34:1
1.00:1
0.68:1
n/a
TKO 600
2.87:1
1.89:1
1.28:1
1.00:1
0.64:1
n/a
TKO 600
2.87:1
1.89:1
1.28:1
1.00:1
0.82:1
n/a
T56 Magnum
2.66:1
1.78:1
1.30:1
1.00:1
0.80:1
0.63:1
T56 Magnum
2.97:1
2.10:1
1.46:1
1.00:1
0.74:1
0.50:1
WHERE THE MONEY WENT
Item:
Price:
Hurst five-speed swap kit
$3,445
SFI bellhousing
$250
Hurst billet steel flywheel
$150
Hurst strip/comp clutch
$345
Total:
$4,190
THE COST SO FAR
Item:
PHR Issue:
Price:
’65 Olds Cutlass
Jan. 2010
$7,500
DSE four-link suspension
Jan. 2010
$2,345
DSE front suspension
Feb. 2010
$3,982
Baer front and rear brakes
Mar. 2010
$2,670
DSE brake booster
Mar. 2010
$375
DSE steering kit
Apr. 2010
$399
Strange S60 rearend
May 2010
$2,295
SAM 461 big-block Olds
June 2010
$8,504
Hurst five-speed trans
July 2010
$4,190
Total
$32,260
Five Speeds or Six?
In addition to the three different trim levels offered by Hurst Driveline Conversions' kits-Basic, Deluxe, and Elite-Hurst offers a choice of either a Tremec 500 or 600 five-speed, or a T56. To help Pro Touring aficionados decide between them, here's a quick breakdown of what each has to offer. The Tremec TKO 500 and 600 are an evolution of the TR-3550. These extremely stout gearboxes are rated at 500 and 600 lb-ft of torque, respectively. While the TR-3550 was designed to work in concert with meager stock V-8s, the TKOs feature larger gears, tapered roller bearings, a beefed-up case, an internal three-rail shift system with cast-iron forks, 4615 alloy steel gears and shafts, a stronger single-piece countershaft, and a short-throw billet shifter. Furthermore, the TKO has provisions for eight different shifter locations, three crossmember mounting locations, and electronic and mechanical speedometer pickups. The TKO 500 has a deep 3.27:1 First gear, while the TKO 600 has a 2.87:1 First, which accounts for the difference in torque capacity. There's also an option to choose between a 0.64:1 and a 0.82:1 overdrive on the TKO 600, while the TKO 500 has a 0.68:1 Fifth gear. We opted for the taller 0.64:1 overdrive ratio with Project Olds, as we felt the 0.82:1 overdrive was intended more for road race applications. Factoring in its strength, versatility, and affordability, the TKO is the most popular aftermarket Tremec overdrive by a large margin.
Hurst includes reproduction GM "621" bellhousings with its kits, but set us up with an optional Quick Time SFI unit. Before installing the clutch, Jarvis tightened the bellhousing to spec and attached a magnetic dial indicator to the crank to check for runout. Hurst recommends a maximum of 0.005 inch of runout, which ensures that the input shaft of the trans will align properly in relation to the crankshaft. As it turned out, the bellhousing was positioned too far toward the 8 o'clock position, so it was moved closer to the 2 o'clock position using offset dowel pins. Jarvis attributes the initial misalignment to poor manufacturing tolerances when the Olds block was originally cast.
For those who need two overdrive ratios, the T56 Magnum is the new king on the hot rod block. A new and improved version of the venerable T56, this is the same transmission used in new fifth-gen Camaros and C6 Corvettes. Tweaks include larger input and output shafts, larger and stronger gears, an improved heat treatment process, a stronger case, double- and triple-cone synchronizers, laser-welded dog teeth, stronger shift forks, and shorter throws. The result is an astounding 700 lb-ft torque capacity, which is more than enough to handle the healthiest of big-blocks. For added versatility, the Magnum has multiple shifter locations, mechanical and electric speedometer pickups, and is compatible with both cable and hydraulically actuated clutches.
