what is really the difference between the arp head studs part number 154-4001 and number 154-4005. It says one is for factory heads and the others are for basically any aftermarket. But what is the difference. thanks
For stock heads with stock sized holes yes. For after market or 351 heads with larger holes, no. U need them to make it fit right. Don't want too throw a hot dog down a hallway do ya?