Quote:
If it is off by .050"
The only way for your cover to work is to modify the dowel holes so the seal "self centers" then tighten the bolts. However you may run into issues with bolt hole alignment and have to modify those also 
If you just replace the seal using the same cover "unmodified" the problem will never go away regardless if it has a slinger or not
I'd buy a quality timing cover or a used O.E.M. install a new seal and be done with it 
This type of problem and fix are pretty common on Slant 6 motors with stock covers. Once lined up properly and bolted down, the modified covers seem to do the job.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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