I just put a set of Gil's on my 20 sutphen and it has a very high set of holes in the transom.

It also has two holes lower near the drive that have not been cut out through the back.

What is the best place to exit?

Will the higher straighter exit cause problems with reversion etc.
How straight can you go?

Thanks in advance for any thoughts.

No one has any input on exhaust angle.

I want to get my boat in the water this weekend.

if the pipes are dry all the way back, no angle is ok ,or if the riser has a decent curve that transitions to flat, that's ok....don't run any wet exhaust at a flat angle or water will find its way back into the motor, no matter how high it exits..best bet is to have manifold/riser joint above the outlet..yet don't try to bend the rigid wet exhaust hose, the bends should be designed into the riser itself or the tips should exit at an angle so the hose remains straight like on some imco set-ups..hope that makes sense...
c

Well it would but I have seen alot of guys running stainless marine pipes almost flat.
10 degrees or so.
Thats what My pipes have is 10 degrees, but then I read on hear you need 14 inches of drop.
Our old sutphen exited very high in the back of the boat as well.
Above the rub rail.
It always seemed to work fine!
So I am not sure whats correct at this point.

Exhaust hoses / pipes should not be higher at any point than exhaust elbows.As CG pointed out hoses should be run straight, with Gils you should have a 1/2" drop per foot minimum it would be undesirable to have anything less! make sure you come out above the water line with the boat at rest in the water or you will suck in some water there as well. Harden marine makes wedges for Gils that should get you where you need to be. It would be a good thing to raise your idle to 850 rpm.With a marine profile cam thats not to agressive you can minimize your reversion The only way to illiminate it is to run dry pipes real high. good luck SC

It would be a 1/2 per ft but not much more than that. I only have 22 inches to the back of the boat from the rear riser bolt.

The drop would be about 2.5 inches.

I would go 14 to 16 inch long riser pipes( with water) and then 4 inch hose connection then the rest would be thru hull fitting.

If I were to go with a more drastic drop and come out by the drive (original location) half the pipe opening would seem to be under water at idle. It would be about 3 inches per foot drop though.

I have some pics of other guys risers that have about a 10 degree pitch but I can't seem to post them here. most of the stainless marine set ups I see are this way.

They have the inner pipe longer by about 3 or 4 inches. mine don't, but It could. (tig welder)

I am sure I am over analizing this but I don't want to have problems later.

If I go out the top I can go silent choice pretty easy too.

I may put a spacer in to raise the riser and then go out the top Just for a little more pitch.

Thanks for the help I really appreciate it.

My pipes work fine. They are strait out but the stern sits so low in the water it doesn't cause a problem.

Those risers come up quite a bit higher than mine but its the same basic set up.
I even have the same o ring'd thru hull covers on the back in the same location.

I think I am gonna go out the top so I can put silent choice on her easily.
That is a sweet looking sutphen.
I always wondered why so many race boats were small block boats?
Thanks for the pic.
Its much appreciated.
Thats how our 30 was set up too.

Here are a couple of examples of SBC straight through exhaust.

This is an off-set setup on a BBC.