Hi

One of me guideplates snapped of on my 540 Merlin BB, so ordered a new set of Comp Cams #CCA-4806-8

But they doesent fit very well, I can torqure them, but there is tension on them, and they cracked in the alloy in one place ( the whole guideplate didnt cracked, just the alloy...I think..).....is there a special guideplate to Merlin Aluminium heads?.....and this isnt the Merlin III heades, It is a special edition Merlin Gumpy Jenkins Edition Aluminium 345 cc heads... I tried my old stud girdles (Fit stock GM heads) but It didnt fit my Merlin heads.

Next question, my new rocker studs doesnt fit tight in the guideplates, because they have threads up to the hex. Does it matter? (My old rocker studs had a shank under the hex so they fit tight in the guideplate....

I ordered the ARP-334-7204 rocker studs, and the text says "Guideplate locator shank - YES", but there isnt any shank....they look just like the pics at summit.

Need some help

Thanks/ Kristoffer