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I have installed a 4.3L in a 1949 chevy pick-up with EFI, computer, the works. (In case you are wondering...Yes I know it's not a 350, and I did it because I wanted to)

I am trying to mess with the idle, guages and such but don't have an exhaust system on it yet. All I have are the headers bolted on. I was told that if I run the engine and let it get hot and then cool too quickly there is potential for the valves to crack. Is this true?

I was planning on getting it running and then driving it to the exhaust place...is this a bad idea? How do you guys do it? I can borrow a trailer and possibly get it over to get pipes put on but it doesn't run good enough to get it up on the trailer yet. How long is to long to run one without exhaust?
 

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If you can drive it there safely without getting a ticket, it won't hurt the motor. I assume the engine has coolant and the fan works, has proper oiling etc. just no muffler and pipes.
 

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Tow it, trailer it, drag it with a rope anything but drive it. No you won't hurt anything but if the man catches you you are in for a world of hurt and it's not like they won't hear you. As a matter of fact when they caught me they said they just followed the sound. :(
 

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runnin the engine with open headers is not goin to hurt the motor, its when you shut it off is when the damage will occur unless you take proper precautions. I generally stuff rags in the collectors to prevent the rush of cool air back into the headers. this practice will allow the valves to cool at about the same rate as the rest of the engine and will prevent valve warp and seat crackin. and youll be able to drive the thing on the trailer. just make sure you put the rags back in after you get it up there...good luck
 

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i have never had a problem with valves running open pipes. i ran a 400 s.b.c. in a '75 landcruiser with open pipes for almost a year before getting any mufflers on it. no damage whatsoever. you want more proof? imca super stocks and sprint cars, headers right out the side, five grand for 25 laps, no problem. :eek: also, fyi, there is a clause in the law for "working on a macine" and if you do get pulled over just tell the cop your'e in transit to a repair shop. if you really want to go all-out call ahead and get a police escort. yes, it is true.

[ May 07, 2002: Message edited by: middspecauto ]</p>
 

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escorts are dictated by local ordinance and stare statute. nobody will ever get an escort in ILL. you will get told that they dont have time for that and that that is not their job. also that is what tow trucks are for. I vote trailer it there drive it home
 
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