5.7 ltr. Merc 1990-Thermostat Housing replacement-hose placement

[Richard57]

I purchased a new thermostat housing assy PN#860256A1 (Design III- Alpha) for 1990 Merc Cruiser 5.7 Ltr engine Alpha 1 (S/N OC679275).(Port side).

I do not have an updated schematic showing the new hose routing, for the Design III THERMOSTAT HSG. I am confused as to where to attach the 4 hoses on my original Engine to this new Thermostat Hsg.
There are 2 hoses that connect from the thermostat hsg to the underside of the exhaust manifolds, and 2 more hoses that connect from the thermostat Hsg to the top at the exhaust elbow. Therefore my question is do I eliminate the top hoses on the exhaust Elbows or downsize to a 3/8” dia hose to fit this new thermostat housing?

Also I would like to know the proper placement of the temperature sending unit on this new thermostat housing

My part supplier could not answer my questions and advised me to contact you, I would really appreciate a quick response as I am perplexed on what to do

 

[AllDodge]

The temp sender goes on one side of the thermostat housing. Doesn't matter which side

You will plug the elbows where the hoses use to connect above manifold
Need flow thru gaskets part number 863724 between manifold and elbow (assuming you don't have riser extensions)

Pic is for Big block so pay no attention to item with Note 1 on it.

 

[Richard57]

I appreciate this info, it’s difficult when I don’t have the proper schematics. This helps alot

 

[Richard57]

Are you able to give me a link to find this drawing online?

 

[AllDodge]

It's from a service manual, and can be found in a few different ones.
Manual 17 page 6A-21