Need Help With Exhaust Plumbing

[DonziDave]

Hi Guys - Sorry no pictures, but I will try to explain my confusion...!!
I bought a non Donzi project boat that came with a set of exhaust headers that I would like to put on my Donzi 18 SBC if I can get them configured properly.

They are a set of 20 year old Edelbrock model M1 aluminum headers that are brand new...never installed.

They are missing the risers and I am looking for a set or ones that are adaptable. Exhaust opening is 2 3/8" with a 4" dia. 3 bolt flange. Any help would be greatly appreciated.

My problem is the water plumbing setup. Both the water inlet and outlet are located on the front of the headers. They came with a thermostat housing that has a 4 hose diverter block mounted to the top. The hoses are 3/8" i.d. aircraft type braided The hoses are equal length and only long enough to reach the inlet/outlet fittings. This makes no sense to me. How can the water circulate if the supply and discharge are connected to the same terminal? I would think that only the inlet hose would connect from the T-stat housing and the outlet hose would connect to the riser fitting and the water dumped out the exhaust. Am I missing something here....????
Also, the 3/8" hose size seems small.....any opinions?

BTW - fresh water only.

Thanks in advance for any help.
Dave

[mphatc]

Likely the water exits into the exhaust stream inside the down leg of the risers.

Mario

[MOP]

Check link below spotted these on Ebay the other day, just what you need! It is possible that the manifolds are two pass, the water goes in down to the other end and U trns back out. This was common on some older setups in fact OMC used it for years, put a hose on and run water throught to see if I might be right.

Phil

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&rd=1&item=4542126437&category=31285

[DonziDave]

MOP - Your description of the flow in the header is exactly how it is constructed, but why would the outlet water return to the T-stat housing?
I saw the risers on ebay, but they have a 3" opening with a 5" flange. Think they could be fitted by making an adapter plate?
Dave

[MOP]

The header to riser joint is dry you should be able to work that part out. The two riser feed nipples off the Tstat housing flow free the other two are Tstat controlled, check to see which two get water without restriction plumb them to the risers. They used small hose to regulate the flow, it worked fine contrary size wise to what we use now a days.

Phil

[DonziDave]

Thanks MOP - Good info....!!! If I can buy the risers on ebay cheap enough, it might be worth trying to adapt them.
Thanks again - Dave