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1971 Chevrolet Nova - Project SuperNova, Part III

Swapping In A Rebuilt Turbo 350 With A B&M Holeshot Converter And Pro Ratchet Shifter

Photography by Matthew King

OK, so maybe on second thought, running a stock Powerglide and converter behind a 540hp engine last time wasn’t such a good idea. Call it an experiment, but all we proved during our SuperNova project car’s maiden voyage down the quarter-mile was that blowing up the converter and not being able to shift the car leads to really bad track performance. A 15.80 at 95 mph wasn’t exactly what we were hoping our ’71 Chevy Nova would run after we swapped in the thumping 383 small-block, but we fortunately already had a better transmission, converter, and shifter ready and waiting, and the stock ’Glide was cast off in the driveway virtually as soon as we got home from the track. Swapping in the rebuilt Turbo 350 with a B&M Holeshot 3,000-stall converter and Pro Ratchet shifter took about a full day’s work, and the results were well worth the effort.

We trucked a junkyard TH350 core to a local transmission shop and had it rebuilt using a B&M TransKit, which incorporates heavy-duty clutches, new seals and gaskets, and provisions to convert the valvebody to manual/automatic operation. This feature allows you to select your own shift points by shifting the transmission manually through the gears, or to simply slap it in D and let it shift itself.

Bolting the TH350 in place of the Powerglide is so straightforward it barely merits description other than to say it’s a direct bolt-in. If you intend to keep the stock column shifter, there are kits available from resto companies like Year One and Classic Industries to convert the shift selector to three-speed operation, but if you use a floor-mount shifter like we did, there’s nothing to worry about. The crossmember, trans mount, and driveshaft can all be reused with no modifications. You may have to tweak the cooler lines slightly, but we needed new ones anyway, so we got the proper TH350 parts from Inline Tube.

At the track, driveability and performance improved dramatically (see “Dragstrip Results” sidebar), with the high-stall converter and three forward gears keeping the engine in the sweet spot of its powerband, but the car still has a horrendous traction problem with the 3.08-geared pegleg rearend and radial tires. On one pass, we smoked one rear tire for 1,200 feet! We also didn’t have a tach to monitor shift points, so this outing is far from the car’s full potential, but we’re getting there

SOURCES
B&M Performance Products
8-18/-882-6422
bmracing.com
Inline Tube
33783 Groesbeck
Fraser
MI  48026
810-294-4093
BFGoodrich Tires
877-788-8899
www.bfgoodrichtires.com
Wheel Vintiques
5-59/-251-6957
wheelvintiques.com
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