GM 700-R4 & 200-4R Boost Valve and Sleeve This Boost Valve and Sleeve Kit from Superior will improve all 700-R4 and 200-4R Transmissions. This Problem Solver replaces the worn out O.E. aluminum valves and is made of hardened steel to resist wear. The valve boost diameter is set at .471 for higher boost capacity and proper tolerance is assured at bore mating surfaces.