1993 Big Block Ford Mustang - Hybrid Drive

A big bonus of using the patented cast aluminum J.W. bellhousing (PN: 92454-A) over a cut-to-fit adapter is that it's 600 times stronger than stock, and doubles as an SFI-approved flexplate shield. Throw in the fact that it costs just a smidgen more than a flexplate shield at $300, and the decision is a no-brainer. With over 40 different Ultrabells in its catalog, J.W. probably makes something for whatever motor/trans hybrid combo you can dream up.

To complete the TH400-to-BBF adaptation, J.W. also offers a matching flexplate (part No. 93001) and crank spacer (part No. 80002-1) to ensure proper torque converter alignment on the input shaft. Essentially a BBF flexplate with a TH400 converter bolt-pattern, this J.W. piece is SFI certified and boasts a replaceable ring gear. It's offered in both standard- and lightweight trim, but for our straight-line application, we went with the heavier model.

After loading the forward clutch drum and input shaft into the case, it's time to bolt up the J.W. Ultrabell. This ingenious design bolts through the pump body and into the case using longer-than-stock bolts. TH400s were produced in both six- and eight-bolt front cover configurations, and the J.W. bellhousing will work with either case design.

Proper line pressure is critical in order to reliably engage the clutches and bands in a performance transmission. The orange pressure regulator spring used in our build provides just the right amount of tension for our application.

The primary objective of our TH400 is to endure the rigors of track abuse, but it will also need to be friendly enough for the 200-mile roundtrip to and from the strip. Consequently, Phoenix installed a forward-pattern semi-automatic valvebody. This enables manual shifting capability at the track, but will also shift itself on the street with the gear selector in Drive. Opting for a transbrake would have required a less-street-friendly full-manual valvebody and a reverse-pattern shifter.

Phoenix includes a custom-matched and balanced torque converter as part of its transmission packages. It optioned our converter with a heavy-duty one-piece front cover, reinforced fins, a machined billet hub center, bronze support bushings, Torrington bearings, extra long input shaft splines, a hardened pump drive, anti-balloon plates, and beefier springs and sprags. Since our project Mustang will be fitted with relatively small 275/60R15 drag radials, we had Phoenix set the stall speed at 2,000-2,500 rpm. While that may seem a bit tight, our big-block Ford kicks out 673 lb-ft of torque, and we'd rather take a conservative approach while dialing in the chassis to prevent blowing off the tires. If the car hooks hard and needs more grunt out of the hole, we'll have Phoenix loosen the converter up in the future.