guide plate milling

[Dusty]

bridged heads

IIRC it is .250 and then another .125 for the guide plates

so final milling would be .375 to retain stock geometry with 1.6:1 harland sharp roller rockers using arp 7/16 base 3/8 studs.

i shouldnt need longer pushrods (stock being 7.800") unless i go deeper or use crane roller rockers. i seem to recall years ago doing one with guide plates and going too deep or the combo of that and crane rockers and the result was needing .100 longer pushrods @ 7.900" to keep geometry correct. i may still end up needing the longer pushrods but i'll check that when i put her together



drill and tap studs to 7/16


Any feed back or corrections on that info machine shop going to work on this in the next day or three.

[fuzz401]

when done I would still check the push rods for the right length

[tufcj]

You'll still want to check the geometry. I have 291C heads on my 69 390 with Crane gold rockers. It took a .100" longer pushrod to get the tip placed correctly on the valve. Be sure you use hardened pushrods designed for guide plates.

You're machining specs are right, it's about .250" + the thickness of the guide plate (usually 1/8" or .125").

Bob
tufcj

[Dusty]

thx

they are 5/16 correct? i've got 2 sets of .100 longer and 3 o 4 sets of the stockers hanging around here, when i assemble the little bugger i'll be checking for geometry

[tufcj]

Pushrods are the same as SBC. Stock length was 7.797", 5/16" diameter.

Length will depend on the base circle of the cam lobes, height of the lifter, rocker brand/type, even the valve that is used and how much the seat has been machined. If you have the head machined for adjustable rockers, it's another variable.


Bob
tufcj

[Mudrat]

Damn I love this site!!!

Good gouge on guide plates :-) I have another 360 build coming up soon :?

[Dusty]

can't remember the ARP part number but if someone is looking this up there are two options 7/16 or 3/8 studs

i believe they were chevy small block arp studs for the roller rockers. Anyone have the part numbers to post

the base thread is 7/16 so you will have to drilla nd tap the threads

[IslanderXJ]

So with the http://www.bulltear.com/catalog/product_info.php?products_id=184 HD guideplates
and http://store.summitracing.com/partdetail.asp?part=CSP-S4004-7&autoview=sku HS Roller Rockers
the rocker bosses would need to milled down .425" ? :-|

Anybody have any luck finding the ARP part Number for the studs, one of these:
http://www.arp-bolts.com/Catalog/Catalog.PDF/ARPCatalog_0046.pdf :idea: ?
I was thinking one of the ones between, but not including, the "Mark V" and "Chevrolet big block (aluminum heads)" lines.

[tufcj]

I used ARP studs for the SBC with roller rockers (ARP 134-7104). I used 3/8" Crane gold rockers on the early stud type heads (291-c).

Bob
tufcj