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Discussion Starter · #1 ·
My 66 289 2bbl coupe is about to hit the road. It has air conditioning, power steering and power brakes.

During restoration, the engine was rebuilt. In the process, it had to be bored. Unbeknown to me, and I just discovered this yesterday, it has been bored .040 over, and I am very concerned that it will run hot. Anyone got any feelings on this and any advice onwhat to do to keep it from running hot ? It has the 3 row, oversized radiator, and this should help. Am I overly concerned ?
 

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Why do you think .040 over will make it run hot?
 

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the normal 289/302 is a brute of an engine. 40 over should not present any significant problem. Even at 60 being the limit, the engine would still run okay providing it was rebuilt properly. Use a 180 thermostat and insure that all the coolant flows freely during engine operation. Always purge the cooling system of air pockets prior to sealing it up. Also take note that you should never measure your cars temperature with idiot gauges. For breakin I would mount/install a temporary digital gauge to measure the real/actual temperature of the engine. An engine that is well lubricated and has suffiecient cooling can idle/run for any amount of time and not get hot.

Mark Vasquez
 
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You are worrying about something you havent verified yet...why dont you get it running first and see where you are at?
 

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Discussion Starter · #9 ·
Thanks to all of you for your comments. I am so concerned about this because my trusted mechanic told me that he had a mustang like mine and it was bored .040 over, and everytime that he took it out for a spin and had to stop at a long redlight or got caught in traffic, his car overheated. I guess I am just fearful that my beloved and prized car will not live up to my expectations and I would hate to lose the origonal engine and have to replace it with another.

Thanks folks for understanding !
 

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My coupe's 289 was bored .040 over in 2001. It's never run hot, including on the 113+ miles that I drove on the Pony Trail in Utah in 2004.
 

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Discussion Starter · #11 ·
Thanks Laurie, every time that I get a reassuring comment (ncluding yours) it makes me feel better. Just understand, this was my first car and I hsve owned it since 1976 and it is , I guess about the only thing of my youth that I have held onto ! The hair is getting thinner, the waist is a little thicker, the eyes are a little weaker, the knees are a little stiffer, and that is all I will admit to ! But, I still have my old 'Stang.
 

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Also if it does run hot don't automatically assume its the overbore. There are dozens of other more common things that will make it run hot. I've run dozens of big blocks with overbores and stock radiators and never had issues even on the warmest days.
 
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