hello. i have a 1985 formula 25pc with mercruiser 5.7. i recently purchased a new oem merc manifold kit. but the risers on new set are different(4 inch), and my old risers where 3 inch. someone told me the new risers i have where 1987 and newer. my question is, will this new kit fit on my 1985 y pipe set up if i swap the (3 to 4 inch) boots with( 4 to 4 inch) boots? or should i start trying to return these risers? someone else told me that the old ones i need are discontinued and these will work. but i am hoping to get some information that is solid. thanks