[lil64gto]

I am wondering if I changed my Super Turbo 14" mufflers to 40 series Flowmaster, will it lower my temperature.

I was talking to a guy that has a 65 tri power last week and he told me that when he changed over from the Dynomax mufflers to Flowmaster 40's his temperature when driving on the highway went from 210 degrees to 180-190 degrees.

When I drive 55 my car the temperature stays around 190 degrees, but when I drive about 65-70 MPH the temperature jumps up to 205 - 210.

I have a desert cooler 4 core radiator, I had the original water pump rebuilt and the engine is .030 over with a slightly hotter cam. The thermostat is 160 degree and the exhaust system is the factory manifolds with 2.5" mandrel bent Flowmaster pipes.

I went with the Super Turbo's because they had a better flow than the Flowmasters. Do I need a little more back presure on the exhaust?

I am open to suggestions.

Thanks

Jim

[Geoff]

All my V8's do the same. Nothing I did would stop a little temperature creep once I got to 60+mph. What DID help & keep the temp increase to a minimum was to use a 19" flex fan [ replaced a good clutch fan ] & smaller water pump pulley. Yeah, I know the fan is not supposed to do anything at these speeds. Not on my cars.
I think the problem is the design of the cooling system. At 70mph, there are twice as many power strokes from the engine producing heat compared to 35 mph. But you have no increase in water volume or radiator area to dissipate this increased heat.

[Bad Karma]

Did you read the thread about Water pump clearance titles chalk another one up to the cast impeller? I also have a trick that may help and a few others have tried it on the board with similar results. Drill 1/4 inch holes in the brass surrounding the middle of the thermostat. 12 oclock 2 4 6 8 10 oclock evenly as possible. On every car I have tried this it averaged a 10 to 15 degree drop on the highway. The last person from the board reported a 15 plus degree drop and was VERY Happy with the cheap mod. To be truthful I have no Idea why this works but if done right and everything else is ok working order its good for atleast 10 degrees. I have had the same results about 6 times on all different makes and models 2 of them being older ponchos. AN old racer told me this one in the early 90's. Hope it works for you too. You leave the valve in the middle operational your just going for a little more flow here. Looking at your temps you should get down close to where you want to be with this. Please let me know if you try it how it works out. I searched for the thread with one of the members response who tried this and was happy with the drop in temp but Its no where to be found. It was in the old forums but after 30 pages of looking I gave up.

[dave bolduc]

switched from a very restrictive GArdner stock system to x-pipe new setup....sounds great...temps the same sadly...i had hoped the same