I think the main difference is that the 55-87 rockers are non self aligning. They will work fine in the LT1 with guideplates. Just make sure you use GMPP guideplates.

 

oh ok thanks. anybody have any problem with these PRO-66915 they are proform rockers from summit

 

IIRC proforms are a hit/miss situation. I think Dwayne had some on his caprice. can't remember if he success with them or not.

 

I thought his were CAT. Or are they one in the same?

 

so proforms are not too good?

 

Good topic.....I would like to know this also as I too am looking for a set....If we can use standard (55-87) sbc rockers with guideplates then that is a good way to go....my brother has a set of harland sharps on his 69 bird and has had good luck with them.