overheating and slowing down: Bad fuel or Bad thermostat?

[CCTVED]

OK just returned from Ambrose Lake Michigan few days ago on the way there my 454 P30 ran awesome until we got 30 miles away no big deal figured I would replace fuel filter did that and ran fine almost all the way home started running ruff around 62 mph it breaks up and want to  slow down to 55mph I noticed that my factory installed thermostat gauge is all the way over on HOT so I turned the heater on and it cooled down and got it back up to 62mph no problem... My question is could it be a thermostat problem or something in my tank..
Eddie

[gpw9552]

Start with changing the fuel filter, again.

While you have the filter off, check for internal rust in the lines.

I had to bite the bullet and have the tanks cleaned and coated.

[legomybago]

Make sure your clutch fan is working.

Check your lower radiator hose too, might be colapsing? Should have a spring inside it I believe.

Very well could be time for a new thermostat and replace anti freeze, radiator cap

[cncsparky]

Sounds like two separate issues that could be related.  I would work first to find out why it overheated, once fixed it might run ok afterwards.  Depending on how hot, it may have caused it to run rough.

Definitely recommend installing an aftermarket coolant temperature gauge.

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Ok iam picking up thermostat and aftermarket guage and enough fuild to replace it all
Will let you know how that works

[CCTVED]

Oh yeah what size thermostat do I get a 180?

[legomybago]

180 would be fine I'm sure

[DonD]

I run 180, all good.

[CCTVED]

Picked up a Temperature gauge and thermostat installed both and all is good thanks for all the Help

[tntwardell]

If its carberated its probably not the filter a cloged filter would cause the float bowel to not stay full and at that rpm would run out. Of fuel and stall. Check the timing and vacuume advance. If not enough advance at crusing speed it will run ruff and overheat. Thermostats get stuck and dont usally fix ot self by slowing down i bet its time for a new distrebutor

[GONMAD]

Hi Guy's While I have been running these things hard since 2005 pulling excessive loads I've burned up three clutch fans & been through several thermostats, I've found a safe way to regulate heat.
First   look for a "FAILSAFE thermostat. If it fails it remains open & doesn't destroy the engine.
Second   I switched to a High performance  427 CORVETTE dual stage thermostatically controlled clutch fan hub It's quieter & heavy duty. It will outlast the stock P 30 unit & NOT make all the racket the stock one will.
Third Install a 12" or better auxiliary cooling fan in the upper corner of the radiator or wherever the upper return hose feeds coolant back to it, Have it come on with the key & STAY on. Use a relay to provide power so as not to put a strain on the coach wiring.
Fourth  Install an aftermarket aluminum High performance water pump  use the WEIAND Action plus. It has extra large bearings & flows much more than a stocker & does it without drawing more HP from the engine.
My rig usually runs around 200 to 210 degrees even towing a large trailer. I hope all or some of these ideas work for you or everybody as good as they've worked for me.
GONMAD

[Oz]

Picked up a Temperature gauge and thermostat installed both and all is good thanks for all the Help

Does this mean the overheating/slowing down problem is fixed?

[CCTVED]

everything is all fixed no more over heating thank you for all the help