One of the great features of the Dart Special High Performance (SHP) small-block is its provisions to use OEM hydraulic roller lifters.
There are mounting bosses in the valley for a factory stamped steel spider, and the lifter bores are machined flat on top to accommodate the “dog bone” alignment bars used on OEM hydraulic roller lifters. This allows an engine builder to take advantage of the fast acceleration and low maintenance of a hydraulic roller cam pro file while using inexpensive stock-type lifters.
The lifter bosses in SHP blocks are .220” taller than the bosses in early-style blocks that were not designed for hydraulic roller lifters. If you are installing aftermarket lifters with link bars in an SHP block, the lifters must be designed for use in 1987-up or Bow Tie blocks. These late-model lifters are typically .300” longer than early-style lifters.
Due to the additional length of these aftermarket tie-bar lifters, they must be installed in the block before the cylinder heads are installed.