The inner tail pipe slides inside the inner header pipe and the watwr jackets are connected/sealed with the hose. There is no clamp, or way to make a tighter fit and the fitment is very sloppy at best. Thats the point of my reversion

My original plan WAS to seal off those outlet holes in my header, weld a bung in the top and dump the water out the transom. Obviously then the fitment of the 2 pieces wouldn't be an issue if there wasnt any water. Finding out how bad of an idea that was, my new plan is to try to fix the fitment.

There is roughly 1/16 - 1/8" gap when you fit the 2 pipes together. My plan is to weld 3-4 beads around the tail and slowly grind those down until they fit snug inside the header. Then before putting them together permanently, filling the valleys created from the weld with high temp silicone. I'm hoping that will create a water tight seal between the two and relieve my reversion issue...
thoughts?

if the slip connection has a lot of slop, you should be able to take the header and tail to a place that does diesel exhaust, they should have dies that will expand/contract the tubing untill you have a nice snug slip fit, or you could seal the water jacket on each side, ad bungs and a 1" diameter jumper hose like cmi's..just throwing ideas out there

I like the idea of expanding the pipe. It's such a small amount it would have to be expanded that I would assume the dies would have to be highly adjustable to the mm. I thought about running a jumper hose farther down the tail, I'm just concerned about the rubber hose that is making the connection between the two jackets. I'm not sure if I put a bung say 10-12" farther down from that, if it would still build up enough heat at that point to melt it.

About how far down the tail should I put the bung from where the hose slides over the jacket? Not having any water pass under that hose, you dont think itll get too hot and melt? The bung in the header would be roughly 6" behind the hose and if I put the tail bung roughly 6-8" down the tail in front of the hose, there will be about a 18-20" space that wont be getting any water right where that hose is. Will that space generate too much heat for hose?

look at this exhaust.... the cooling water goes thru the hose at the joint. the water jacket on the header and the riser is dead headed with the header and the riser being gasketed/band clamped.

If you try and use exhaust hose without water you WILL burn thru it

(pik stolen from 777offshore's ad)

I would weld up the water holes at the end of the header and at the front of the tail. Then weld in a appropriate marmon flange to the outer pipe. Then weld in a bung on the header and the tail and bypass the water around the joint. I would look similar to the header/tail Phragle posted. 5-marmon-flange-5-756-bead-304-stainless-steel-41968-l.html

Its sounds like something other than the rubber hose will need to be used to make that connection. Another question I had with that set up is, the bung in the tail would only be going through the water jacket not through the jacket and exhaust pipe both? If that's the case, I assume the flow will just be natural out the back end of the tail since it wont hit any exhaust until the mufflers.