PCE281.1654 Speedmaster heads for 360 LA

It’s interesting to hear all the “tight guide” responses.

If bought as “assembled heads”, I can’t think of any import heads I’ve had in the shop in ages that had tight guides.
The guides are usually right at about .3430”, and the valves are rarely over .3413”(and are typically.3405-.3410”).

If you’re building them up from bare heads, and using more “name brand” valves, you can get into guide clearance issues, as the valves can have .001-.0015” larger stems.

I just had a set of assembled SM Olds heads here to look over. Guide clearance was between .002-.0025”.

Should they be checked out?
Yes, it’s a good idea.
It’s the only way to know what you’ve got.