Need help with hot spot on 454

Will try to make a long story short. Starboard 1988 454 FWC with 1400hrs, bought boat with about 950hrs. This motor always seems to run 5-10 degrees hotter than port and every other year or so this motor seems to have an issue with getting too hot - right now is running just over 180 at 3000rpm cruise - port motor runs a steady 168 or so.

So in trying to diagnose overheat and running heat gun noticed this motor has a hotspot on the left side of carb (see pic) that was up to over 400 deg just in this little 2"x2" area can see. I painted this spot a month ago and already buened off paint. Scanned other side of carb annd other motor and this area only seems around 250-300 deg or so. Mechanic said there is a block off plate at gasket here as is where exhaust is?

So still seems too hot to me and wondering if this might have something to do with this motor always running hotter? Is something need o be concerned about? If yes where do I start?

Thanks Ryan

That's the exhaust crossover. It is normal for that area to be hot and for the paint on the intake manifod to be burned off in that area.

Yes, that spot does get hot, normally. A note on the "block-off" plate/gasket. There are options for the 454 for full exhaust crossover, partial, and blocked off. You do not want blocked off or full. In the Felpro kit, the intake gasket comes with stainless steel restrictor plates for the exhaust path. Those should be used.

Just be careful of any changes you make.

That path is in the manifold to get the intake "warm" as soon as possible. It aids the carburetor significantly in its quest to vaporize the fuel, especially when "cool" or "cold".

Judging by your photos, this is a raw water cold engine. This feature can magnify the cool and cold effects noted above.

Just some thoughts to keep in mind.

I have this exact same photo of my intake manifold BOTH before the rebuild and shortly after the rebuild and as all have said, very common.

HOWEVER, this does not justify the higher operating temps you are experiencing and you may well be developing a cooling problem with any of the other components on board. Just keep an eye open so you are prepared.

Take a careful look at the stuff before your raw water pump. A tiny air leak here can cause all kinds of over heating problems. Look for loose pipe/ hose connections, a leaky gasket on your strainer, etc.

Jeff

My '91 454 X 320 hp starboard has always run hotter by 10 to 15 degrees. Tried everything over the years including the heads, which helped a little, but not much. Gave up! Don't like it, but can't fix it, runs great after 20 years and 1100 hours.