An update for anyone using a roller cam. Some 'kits' use the late Ford spring steel spider to hold stock steel 'dogbones' that keep pairs of roller wheels aligned. This avoids all the problems with link-bars but introduces a new one. Specifically, there are no bosses or threaded holes to bolt the spider down in a Cleveland block, so you simply mark the area in the block valley, hand drill & tap the required holes. The area is flat so no problem.... except that, because there are no bosses as are cast in blocks originally designed for roller cams, the bolted down spider will sit flat on the floor and cover several of the valley oil drainback holes. This then causes oil flooding of the valley while running and contributes to low oil volume around the oil pump pickup, due to slow drainback to the pan.
Eons ago, racer Mike Cook built plexiglas rocker covers and a plexi pan to check this on a dyno. He found that at only 5000 rpms, there was about 1 quart of oil left down in a 351-C pan! All the rest was up in the rocker covers, the valley, oil passages etc. Note also the 2 stock cylinder head drainback holes are thin-wall and often not well centered so drilling those drains oversized can fall thru the castings. Plus, one head drainback hole in each (stock) cylinder head is 'dog-legged' around internal carb heater passages and those factory drillings don't match up well in the center. Aftermarket heads may drain better but this is just another reason to use a '10 qt' oil pan with scrapers, baffles & trap doors, on any 351-C engine. The stock 351-C redline is 5900-6000 rpms.
Fix: use longer bolts than is stock for the spider, with washers or spacers to lift the spider up about 0.125- 0.250" off the valley floor. We used gr-8 bolts because of the additional length needed in a 351-C block, and safety-wired them against vibration loosening. When adapting a roller cam to an engine not originally designed for such, it means you are redesigning that part of the engine assembly. Unexpected consequenses usually pop up. Check everything twice!