What is the stock OD of the valve guides on a 5.7L? Are they different than a 5.3L?

Here's why I ask. I have a set of 862 5.3L heads, modified by PRC/TS.

A couple of months ago, I ordered a spring set from PAC when they were on sale. The set came with a set of spring seats. The ID of the new spring seats is 0.570". The ID of the old spring seats is .502". And the guide appears to measure 0.500".

Shopping at other web sites, I find spring seats with an ID .570", but not smaller.

Are these aftermarket guides? Should I be looking for something other than an LS1?

I sent a couple of messages to PAC, but they haven't answered.

 

Bob,

There won't be aproblem with those locators. There are thousands of engines running that setup with no issues.

 

OK. I'm just used to the locators being more precise than that. 0.07" doesn't sound like much, but it sure looks like a lot.