Weird timing tab 383

[sogtx]

So I acquired a 383 that ran Ok but had a huge
quadruple pumper nascar carb ..

Removed that monster , installed a 625 holley

I checked timing , noticed the wierd tab and
just assume that its correct , and my initial
is at 40 degrees .. but car runs good .

I set timing to 15 initial on engines mark
It stalls when putting into gear .

So I increased initial , all better and have 10-12” vacuum

Whats the deal with these timing covers ..

I know I should find tdc and make my own mark ,
But its easier to type at 430 am
Its cold in the shop lol .

Is there a chance that they just slapped this cover on
Because they had it ?
In reference to a 71 timing cover those marks are
way off ..

 

[sogtx]

This is a timing tab that Im more aclimated to
But not on this car ..

 

[493 Mike]

The U-shaped hole/slot was for the factory test sensor.
Mike

 

[threewood]

Find TDC manually on the motor to confirm or deny that the tab is correct.

 

[R413]

That's a late 70's cover with that oddball tab.

Yes find TDC and mark the tab.

 

[XCELLR8]

That is the same cover I have on my 1977 400. In my research, it was a one year only timing cover.