High RPM at crusing speed!!!!!

I need help!! i just got my car on the road and i have a 1972 charger with a 727 trans. with a high stall converter and cheetah manual valve body. and going down the road at 45 mph its running around 2000 or 2200 rpms. and its in third gear for sure! HELP!!

And your issue is?

Assuming your tire diameter is 26-27" and you have a 3.55-3.91 rear gear ratio your rpms are right where they should be.

I have 31" tires with 3.23 gears.

With that combo you should be doing 60 mph at 2100 rpm's and 45 mph should be around 1580 rpm's.

Either your speedo drive pinion is incorrect (should be a 27 tooth) or your speedo or tach is incorrect.

Also, high stall converters and low numeric ratio rear ends often don't play well together, you might be experiencing some converter slip or a combination of all of the above.

This might help. Use 90% as convertor efficency. http://vexer.com/68rt/speed.html

Would it be possible that i need a smaller stall tourque converter??? right now i have a 2800 to 3200 converter i think. and my cam is a .501

convertor slippage i bet. is that a 292 comp magnum cam in that? if so, any less convertor than you have now will probably make the car sluggish. my own car with 440 and 292 magnum picked up 3 tenths with a switch from a 2500 stall 11in. to a 3800 10 in. also have a 3.23 gear. 28 inch tire tho. you sure have a tall tire in that thing. might be time to put a lower gear in it.

Yea that was my mistake its a 27" tire i was thinking of my brothers tires that he has!! But yes it is a 292 duration comp magnum cam!! thanks

Well with 3.23 gears and a 27" tall tire at 45 mph you should be turning 1860 rpm. Now a 27" tire is not a stock diameter for the car so unless you have swapped the drive gear inside the tranny as others have mentioned you are actually going faster than the speedo is indicating which easily could make up the couple of hundred rpm.

Ok thanks!!