Thread: BBC pushrod guide question.

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Pop has a set of 802 heads for a 402 chevy. The push rod guides that came on the heads are 5/16" wide in the slot opening for the pushrods. He just bought 3/8" pushrods for the engine. Shouldnt that call for a 7/16" slot opening? What would that small of a guide have been OE for? Thanks

Originally Posted by jimmyjeep

Pop has a set of 802 heads for a 402 chevy. The push rod guides that came on the heads are 5/16" wide in the slot opening for the pushrods. He just bought 3/8" pushrods for the engine. Shouldnt that call for a 7/16" slot opening? What would that small of a guide have been OE for? Thanks

Yes.O.E.
Make sure always to use push-rods that are hardend for use with guide plates.

Eric, thanks. To clear this up though for me , (I can be a little dense), the 5/16 is O.E.? The 3/8 " is aftermarket size for performance? and we would need a 7/16" slot opening to clear the 3/8" pushrod width? Thanks again.

no oem is 5/16 3/8 and 7/16 gm made all of them the 3/8 and 7/16 were used in more of the hp engines .pushrod all big blocks have guilds so they are hard push rods the size for the 3/8 pushrods are 3/8 push rod guilds and 7/16 push rods for 7/16 the guild can not let the push rod move a round that would defeat the push rod guild plate

Thanks Pat.

yep ok most all the bbc i use the 3/8 pushrods the guild plates can be had from many comp /gm/manley but mark 5/6 are not the same they have a 3/8 bottom stud or tower bolt and are thinner to so if your working on one of them you need to look at this .i drill and tap them for old mark4 studs 7/16 top and bottom s and use the old mark 4 guild plates