Two things I would like to do...

Skip the rubber hoses and go to braided...

Figure out "what" the smaller one is for....

Can I cut this off and weld in an AN bung?
What AN size should I shoot for if yes....

Pic 2.....why is it there? Is this a dump? Can I plumb this to the transom? Is this a good point to grab pressure and temp?

rich. the braided hose size you need is # 18 its an odd size pretty sure its direct from earls .can be ordered from summit or jegs 20 ft only and its a non stock item .im guessing they just order it from earls as well .get the slip om ends as well they are the same as used on hp 500s

the smaller nipple in the second pic is a relief nipple for the rear of the exhaust manifold so water dont get traped when under way..

An 18....good to know. Last thing I want is to restrict.....had a hot spot in two of them before......like 110.... But enough to make me leery....

So fixx.....I get what you mean.....so it is essentially a dump? Is there a reason I can't plumb this through the transom above the waterline? Maybe hardline it into the exhaust stream for a bit more "mist cloud" behind the fukkula?

The little bung on the bottom should have a hose coming from another little bung on the back of the manifold. There should be a little hose that runs from the manifold to the the riser, in addition to the bigger hose on the front side of the manifold that runs to the riser.

I'm pretty sure it's there to keep hot spots/steam pockets out of the rear of the exhaust manifold and you do need it. At least that's how it was plumbed on the last set I worked on.

Gordon....

At 50 bux each.....I'll do it (while hating it with twins) but I am not finding an18.....

16 and 20.....and I would guess 20....lesser of two evils...

Should I expect an issue with a bigger diameter? I'm thinking no...but is this an area where an unbalanced system can f-me?

Deezy."

So what is to stop me from taking the two small ports (manifold and Gil) routing them up (hardline) and combining via "y" then through transom.....as a dump....??

I just want to know if I am screwing up the flow ratio and introducing an opportunity for higher temps.....or pressure that could ultimately make my gil's leak.....

d z explained it better then me..so it would look better and be less cost effective to just get the proper 1'' threaded nupple with a 3/8 nipple coming off it..if you have plugs at the top rear of the manifold i would just go this route so you dont have a long 3/8 hose flopping around..looks cleaned when it goes from the manifold to the nipple on the riser..

AN 20 will be an 1/8" too large and AN 16 is 1/8" too small. I tried both when I needed to replace one of the top hoses on my 525SC and neither would work. It needs to be AN 18 to fit a 1" pipe fitting. I didn't find any AN 18 locally and finally just used 1" rubber heater hose.

The top hoses on my 525SC were AN 18.

rich call earls direct thats what i did .theres no dought in my mind its # 18 i used it on my twins also and bouht a 25 ft length anything bigger or smaller will not work

o.k...Will do....thanks for the input yall!