My 1973 Stage 1 car was running hot late last summer after I purchased it. I knew what a difference exhaust could make from previous experience. Since the prior owner had put a T/A Stage 1 crate engine in it, I figured the stock exhaust system was killing it. The exhaust manifolds were leaking, the down pipes were stock, the mufflers were stock type Midas replacements, and the tailpipes were just 2" with the left one "pieced" together just past the axle. After lots of labor, the new system is in place. M/T headers that I sent to Jet-Hot coatings received "Sterling" inside and out. They now go into 2.5" pipes with an "H". The mufflers are Flowmaster three chambers and the tailpipes were pre-bent for a Chevelle, Walker 2.25". This combination sounds great. Last summer my VDO temp guage showed 210-230 degrees on hot summer days. I actually had to pull over and let it cool down on several occasions. When I drove it today and on other recent occasions, in 84 degree outside air, the temperature was just below 190 at the hottest part of the run. Oh Yea! Has anyone else experienced this kind of temperature drop? There were lots of other advantages to the new exhaust and I sure can't wait to go to the track now.
.... the exhaust system that was in there might of been clogged or very restricted,,,,o No: dont run 2 cool on the temp though...
I'm not at all surprised. After I built and installed my engine in '94 I ran manifolds for a year to allow the bank account some recovery time. Went to T/A headers the next summer and recall a noticable temp reduction. Scavenging the chambers more efficiently substantially changes the characteristics of the combustion process. That's why you should/need to richen your mixture, and in many cases, modify the timing curve after installing headers. Where/when the combustion process occurs relative to piston location in the cylinder has a very substantial effect on how much heat is retained in the block.
Right on Brad! I've already bumped the timing up a few degrees. The car has what is supposed to be a new Holley 850 on it. Since this is my first experience with the Holley, I have to do a learning curve to see what if anything I need to do. Thanks for the feedback!:TU:
