Harleymarlboroman

I have a set of 86/87 14101128 heads with .55+ O.D. valve guides, which I would like to replace.
The only listings I can find for Gen 1 350 Chevy valve guides is .502 O.D.
I have seen valve guide seal listings for .530 guides, which is also confusing.
Where can I find .55 O.D. valve guides, and why do these heads have them? They don't look to be modified, but I could be wrong.
I am exhausted from searching and calling every source I can come across.
Thanks.
Darryl

rklessdriver

The OD of the guides should be .557 to .558".... GM has used this OD valve guide in the factory alum heads for a long time starting with the #128 and still use the same guide in the Fast Burn heads.

Replacement guides are availiable from Precision Engine Parts (PEP) and SB. The PEP guides are made of Phosphor Bronze and the SBI guide is made from Powdered Metal/Steel:

PEP - PN B350VSD
PEP - PN B350VETTE (trim to length)
SBI - PN PN 140-8180 (trim to length)

https://www.precisionengineparts.com/

http://www.sbi-e-catalog.com/

Both companies are manufactures and only sell to their dealer network..... But any local machine shop should be a dealer and should be able to get you either company's product.
Will