I have a 68 Dart with a 170 engine. Drives well, but once it gets to almost exactly 50 mph and over the engine really starts to get loud. Any explanations?

Could be a lot of different things. Can you describe just what kind of "loud" noise you're hearing?

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

I would say it's a regular engine roar...it's like the engine really begins working hard all at once at 50mph. I had wondered if the transmission wasn't shifting and the rpms were going up.

You should be able to feel it shift into 3rd with some throttle pressure. The roar you hear is most likely from the radiator fan spinning at high speed.

Try manually shifting from 1-2 at 25mph, then from 2-D at about 50mph and see if you feel it shift, or if the engine gets quieter. If you don't, or it doesnt, its likely you are getting stuck in 2nd, which could be for a number of reasons.

At what speed does it shift from 1-2?
How full and what color is your transmission fluid?
Have you adjusted the throttle valve linkage on the transmission?

~RDE~

_________________
1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

X2. What fan are you running? Stock solid four blade or has someone swapped in a flex or clutch type fan at some point?

_________________
Casually looking for a Clifford hyperpak intake for cheap.