You may want to get another opinion that quickly, while there is time to change your order. Did you order an MLS?
I ordered a set of Cometic MLS gaskets in 4.38" bore assuming it would be bigger to fit that bore. Not the case at all. The bore size Cometic lists is the diameter of the gasket opening, not the engine bore size. Mine sat around for a while before I checked the gaskets on the block. Now I have ordered a new set in 4.41", I think it was, and they have just the right amount of oversize for the 4.38" bore they are going on.
Now I have on order a set of C5917-60 for a small block with Edelbrock Magnum heads. I ordered those in 4.08" to match my block that is already at 4.04" diameter bore. Can't comment on the C5917-60 yet because they are still a week away, if they stay on schedule. Others are using different numbers with Edelbrock heads successfully, so maybe I should have ordered a different part number to get it quicker.
This is my first time using Cometic MLS gaskets, so I am still trying to figure this out.
