200-4R TransmissionConversion Packages

A TH350-to-200-4R conversion typically requires a properly matched 200-4R transmission and torque converter, TV cable and correct carburetor/throttle-body geometry, torque-converter lockup wiring, transmission mount/crossmember positioning, speedometer setup and appropriate cooler connections. Shifter linkage and other installation components may also need attention depending on the vehicle. One reason the 200-4R is popular for classic GM conversions is that some short-tail TH350 applications can retain the existing driveshaft and yoke, although every vehicle should be measured and verified before installation.

No — and this is one of the most important things to understand before installing a 200-4R. The TV cable is part of the transmission's hydraulic control system and affects operating pressure and shift behavior. Correct cable geometry and adjustment are critical. It should not simply be connected where a TH350 kickdown cable was attached and assumed to be correct. Incorrect TV cable geometry or adjustment can cause poor transmission operation and potentially serious transmission damage.

Often, no — but always measure before installation. The 200-4R is especially attractive for many classic GM swaps because common short-tail TH350 applications and the 200-4R are similar in overall length and use a compatible 27-spline output/yoke arrangement. This can allow the original driveshaft and yoke to be retained in some applications. Crossmember positioning is a separate issue and commonly needs to be moved rearward or changed. Vehicle configuration, existing transmission, driveshaft engagement and driveline angles should always be verified rather than assuming direct fitment.

It depends on the vehicle, engine, rear gearing, power level and how the car will be used. Both transmissions add automatic overdrive to a classic GM, but their dimensions, gear ratios, bellhousing compatibility and installation requirements differ. The 200-4R is especially popular in TH350 conversions because of its compact dimensions and potential to retain more of the existing driveline in certain applications. It is also attractive for Buick, Oldsmobile and Pontiac builds because of available multi-pattern case configurations. The better choice isn't simply “which transmission is stronger?” It's which transmission is properly built for the vehicle's horsepower, torque, weight, rear gearing and intended use.