Question on Poweflow
 

So looking at other photos wondering if mine are correct or why the 1 ports isn't used. (see pic) After rebuild I hooked up just the same.

Thankshttps://cimg9.ibsrv.net/gimg/www.off...a8b127ae0a.png

its determine by water flow also persay water volume flow and the T stat housing design. Some are designed in the mix being warm exhaust risers to aid against condensation forming and running down the internal side walls of the risers.

Some set ups jumper hose from the manifold to the riser - just depends on the set up and design.

Temp gun your risers and see what temps they are running at

Are those risers dry without the 1 inch hose connected or do they have passages from the manifold up through the riser gasket?

https://cimg8.ibsrv.net/gimg/www.off...30c62bda13.jpg
Imco's have a wet joint between the manifolds and risers. If you had the older T Stat housing with 4 exit hoses, 2 of them would connect to the risers.

Thanks will check with temp gun I have check after running and can pit my hand on the risers,,,,https://cimg5.ibsrv.net/gimg/www.off...d50506ea24.jpg

Pic of thermostat housing

When you have the 2 outlet Tstat housing like yours, the hoses go to the bottom of manifolds like you have them.

Thanks this site is always helpful, just an update on my systems, as some of you know I used the Holley Sniper on my motor so far 16 hrs on motor and all seem to be working fine. AFR is good, I have 02 sensors on each side so I can see how its running on each side.

it is best to not have very cold water flow in that water jacket portion surrounding where the O2 s are installed straight thru to the exhaust.

As you mentioned if you can rest your hands on the risers then you should be good to go. As always cooling depends on water flow and water volume.

and like I said warm risers are not a bad thing. it helps against building up condensation internally.

stock mercruiser went back to the check balls / spring and rod in the T stat housing necks that hose over to the riser water flow connections. Why because Merc wants warm risers to help against internal condensation build up in the risers. At idle and low rpms the check balls are barely open allowing very little water flow to the risers. merc wants the risers warm during those times.