Mopar Action On-line – Tech Questions
Jim Stinebaker, St.Louis, MO, 1969 Dodge Super bee 383
My Bee has a totally rebuilt & balanced original 383, .030over, stock 727 & 3:23 Sure grip. Cam is MOPAR Performance part #4286677,specs @ .050″: 231/231º, centerline 112º, lift 0.455/.455″.
MoparPerformance tech told me the cam is just one “step” above the original &should be installed straight up (dots lined up). The distributor is a MOPARPerformance electronic ignition conversion. Engine starts easy, runs smoothwith no miss or hesitation. The timing is set at 14* initial & 34 total.With all this the engine overheats at slow speed & idle, pulls only 13″ ofvacuum & has substandard power getting about 5 or 6 m.p.g. with only 413miles on the rebuilt engine. Probably would run the ¼-mile in high 16’s
One technician said the cam should have been installed with a degree wheelrather than lining up the dots & this may be why it’s not pulling 19″ or soof vacuum as he thinks it should. He also thinks the lack of degreeing inthe cam is causing the car to run like a tired 6 cylinder & maybe why theengine overheats.
I’m told that in the day these 383 HP cars would burn theback tires off & were real performers. Not mine! it’s a real dog! What areyour thoughts on this scenario? Thanks for your input and for and excellentmag.
“Straight up” does NOT mean “lining up the dots”. It means “per the specs onthe cam card”. You have no idea of the actual relationship (phasing) betweenthe camshaft and crankshaft. You probably aren’t even sure where TDC is, soyour spark timing numbers can be take with a grain of salt, too.Overheating, on an basically stock engine, usually points to retarded spark.You need somewhere in the neighborhood of 45-55 degrees total timing (atcrank) under light throttle cruise (initial + mech. + vac.).
5-6 MPG! Where do you think the unburned fuel is going? Out the tailpipe andwashing the oil off the cylinder walls, very much accelerating ring wear.Whatever the problem is, you’d better fix it quickly.