Edelbrock Part # 77739 Valley Cover is designed for use with Edelbrock BV3 cylinder heads and intake manifolds with 4.84” bore spacing. In addition to covering the lifter valley, it also completes the cross flow coolant recovery system unique to the BV3 cylinder heads. This valley cover draws water from individual cylinders and combinines them together at the thermostat housing for more uniform cooling of the cylinders. This design also delivers more consistent cylinder to cylinder cooling. A thermostat housing may be used for radiator return or, if a fill neck is used, a boss on the front can be drilled for a pipe thread fitting.