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Discussion Starter #1
Hello Everyone,

I have a 1990 Baha Cruisers 280 with twin FWC PCM Ford 302HO Motors in it. 4 barrell Holleys.

Well after owning her for the last 15 years, we've decided to re-power. We decided to go back with the 302s(HO-GT40 heads;351 cam) because of their solid reputation, although I was told that Chevy parts would be much easier to find.
I've been lucky so far, as I've been able to get everything either new or rebuilt, except the thermostats. We have the old style tall ones(with the bypass system), and ours were stamped 160. I've looked everywhere, only to find that PCM no longer has them and now has only the 145 or 170 tall versions. I know that the 145s were preferred for RWC systems because of salt crystallization, so I went ahead and ordered the 170s. My motors ran religiously at 175 with the 160s. My question is.....has anyone made the switch from the 160 to the 170? What was your result? I know that the hotter they run the better fuel economy i will get, but I know I'll get nervous as they could creep up to 185. That's not a whole lot of leeway to overheat if I pick up something in the strainer or eventually get a small blockage in the system somewhere. I don't really want to switch most of my cooling system for a 10 degree change in thermostats! Any help/thoughts would be greatly appreciated! Thanks!
 

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IMO how much do you really think your going to save in fuel boats with IB/IBOB suck at fuel i understand but also why change something that works fine now.But then again you could pick something up in the strainer with no stats in there. Is it easy to change the stats out while in the water sorry not much help but maybe a different look at your situation :huh:
 

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Hey Wired...i'm with ya. I should have worded my original post differently. I'm not too concerned with fuel burn(gonna try to dial that in next year!), as I'm sure I'll be getting better than 0.5nmpg with these 30 year old dinosaurs! My concern is the 170 stat vs the 160 and operating temp. I'm not sure if they will continue to run at 175, or if they will jump. I'm assuming they will jump and that has me a little concerned, unless someone hops on and tells me different!
 

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This may be a good question to ask the company you are getting the engines from or who is rebuilding them for you. They may give you some input so you can make an educated decision on the 145* or 170* thermostats. The operation of a cooling system, when the thermostat is closed, is to let the cooling water in the engine block heat up to the desired temperature of the stamping number on the thermostat (such as 170*). When the water in the engine block reaches this temperature, the thermostat opens up and lets the raw water, or coolant in a closed system, circulate through the engine to cool it. If your engines ran at 175* in the past, the thermostat should already be open and cooling the engine. Another thing that you may have to take in consideration is that a new or rebuilt engine now has tighter tolerances then your old engines. This itself may possibly make the engines run a little hotter then before. You may want to get a set of each if not too expensive. Try the 170* at first and see how it goes. If for some reason they do not operate in your desired temperature range, you could try the 145* thermostats. Again, these would be good questions to ask the engine supplier.
 

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If the engine rebuilder used quality parts, and you're using a good oil and filter, that engine should live happily running the the 195-210 range just like an automotive application. HOWEVER given the salt crystallization starts at approximately 160 degrees, I would lean towards the 145s for RWC applications. For FRC applications like yours, you should be fine with the 170s. Maybe start with the 140s for break-in then switch to the 170s afterwords if they're not to expensive. If they are too pricey or your budget doesn't allow for a two sets, go with the 170s.

My Sprotcraft has a FI GM 350 with FWC and the manual calls for a 170 degree thermostat and runs between 180-190 degrees when cruising along at 3600 RPMs.
 

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I have basically the same boat and engines that you have. I run 145's in mine as the previous poster indicated, once the stats reach the temp they are designed for, they open and allow the coolant to do its job. I like it because if there is a cooling issue, I will know long before it has an opportunity to do any real damage. I found my stats on skdim website, but I'm sure you are already aware of that site
 
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