Indeed, the 157T would give you a hair more room at the front of your tunnel.
More info than you wanted to know: There are three primary bellhousing "sizes", with their own flex-plates and torque converter sizes. 164, 157, and 141-tooth. Just be sure you have all three parts matching, and that the TC also has the correct splines for your year C4.
The 141T is far less common, as it was only used on the small-block Mustang II, so a V8 could fit the Pinto chassis. The 157T was most common pre-'72 or so, and 164T since then, but years overlap greatly. The small-block bolt pattern is also used on 240 and larger inline 6-cylinders, and 3.8L V6 and larger, making it easier to find bellhousings. However, the flexplates are not useful on V8s due to different balance, and the converters will stall higher if rebuilt and reused on a higher-torque V8.
Torque converter splines (to fit the C4 input shaft) are 24 from '64 through '69, changing to 26-splines from '70 to '80. 1981-86 used the same spline-count in the upgraded C5, but the converter is thicker (to fit a lockup clutch) and will not fit a C4 bellhousing.
The torque converter bolt pattern matches the converter with their flex-plates, so a 9.4" bolt circle fits a 141T, a 10.5" pattern fits a 157T, and an 11.4" pattern fits the 164T, no matter the overall diameter. Note there are some exceptions to all this, and aftermarket versions of each part to adapt stuff together, so almost anything is possible. Hope that helps.
David
