I have a 89 formula sr1 311 with stock exhaust. It has a 3" spacer between the manifold and riser. Would like to install Gill manifolds with a stainless riser. Is there a off the shelf riser that will work or do I need to custom order ?

Buy a set of eddie marine they are really nice system.
http://www.eddiemarine.com/store/car...l&p=13073&c=63

We have good deals on EMI Exhaust this month.
Let us know.

Does EMI seperate the exhaust ports like Gill's do ?
Will I need to order a custom riser ?
With the riser coming a lot closer to the tail pipe than the factory junk there isn't a lot of room to flex that 4" hose.

Yes, EMI seperates the exhaust ports. No custom riser needed, 3" Taller riser to replace Merc manifolds using a 3" Riser spacer block.