I’m not quite sure what you want , lol

I don’t want Tobias the ugly Merc thermostats housing. Do I need it circulating during warn up or just plug the hose barb on the exchanger?

Tom, I have a dual outlet therm housing that I found at CP. I ran a hose to each barb. There is a bypass from the top of the circ pump to the front of the intake that should allow for movement of coolant until the thermostat opens. It has worked great for me for 3 seasons. Those merc pieces are ugly and expensive I bet.

To do as Roscoe suggests you need to drill and tap your intake manifold for the 1/2" NPT nipple he was talking about. Just like a n auto manifold looks. Pic's available if required.

Yep, I know you had the CP thermostat housing on yours. And you're right, they are pretty ugly. I may see about finding some alternatives. I was putting brackets back on the port engine and tried to see what mounting would look like. I'm not sure I like it much. The thermostat housing I was going to use is a simple swivel 90-degree aluminum piece similar to what CP sells with their kit.

I really didn't want to drill the intakes. I have the tools to do it, but I'd rather not. I could connect the heater core passage to the pump or the heat exchanger. It does the same thing. I'm guessing there's a lot of redundancy in Merc's design.

The other dilemma is trying to figure out how to mount these things. I've been looking for brackets, but they're either NLA or extremely expensive and very hard to get. I saw a really cool set up where an aluminum plate was made to sandwich between the thermostat housing with the exchanger mounted to the plate. Until the accessory drive is all together, that part will need to wait a little.

I didn’t notice that his intake didn’t have that provision. Mine came with it and I just removed the plug

Tom, have you thought about using one of the threaded ports on the top next to the thermostat to recirculate to the water pump. Same as using the traditional location. If you were going to use for a gauge just "T" fitting away.
Just a quick thought.

Yep. That’s what I meant by maybe using the heater core outlet.

Jegs has a sandwich adapter that can support the bypass needs for my set-up.


I’ll be able to route to the water pump and the exchanger though I’m not sure of why both are needed.

I also ordered the heat exchanger brackets, bolts and spacers from a discount Merc dealer. Merc was extremely proud of their brackets (almost $400 each). And big names were only taking maybe $20 off. I got mine for a third of the cost wholesale. They have not arrived yet so I’ll wait on giving out the name just in case it was too good to be true.

Making progress...






The other engine is about the same being ready but I’m waiting on the intake and valve covers to come back to button it up. It’s wrapped in plastic.

If I get some time, I’ll wrap up oil hardware and lines today. I’m lopping off the horizontal shelf where the old filter head mounted. The HP1 head will be bolted to the vertical edge of the bracket, nice and compact. It’ll still be upside down, but I like the presentation and it’s not bad removing the filter if you break the seal just a touch and let it drain back.




Now I need to order new fittings and lines for trans cooling. The old hoses are nothing nice to look at. Some AN fittings and hose will make it look nice. More 10AN should do the trick.

Dyno time scheduled for mid May.

Also, as others elsewhere have said here on OSO, receiving parts is becoming difficult. A number of things I’ve ordered are backordered. Who would have thought it would be difficult to get spark plugs and distributor caps. That’s just a. Small example. Some things I’ve had to change design plans because parts were on forever backorder.

A sign of the times. Hope it gets better soon.