head stud question

[87pony]

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

 

[SQUEEZE&STROKE]

The arp-154-4005 Includes 1/2 in. to 7/16 in. insert washers for cylinder heads with 1/2 in. bolt holes.

 

[87pony]

have been told that the inserts are completely unnecessary? is this true?

 

[squeak93]

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?