olds 455 engine kickback

I have a 69 Olds 455 in my 56 Olds. The engine is mildly built and has 9.5:1 compression with hydraulic lifters, custom comp cam with about .530 lift.
My problem is kick back when starting. This problem started last year. The engine has an MSD ignition.
When I start the car, at times the engine will kick back as if it is trying to throw out the starter. This happens when the car is hot or cold, and sometimes not at all.
This has actually damaged the teeth on the flexplate and I typically replace the starter every 2 years.
I have checked the timing and I am at about 10 degrees with a 35 degree full advance. I have changed the timing to 4 degrees either way with little or no difference.
Does this sound like a starter issue? Do I need a high torque starter?
Or does anyone have any other ideas?

Thanks - Gary

 

Check your timing chain!!!

The Original timing chains had a plastic coating over the gears to absorb torsional harmonic vibrations... However... after a few years they start to dissintigrate... causing the timing to fluctuate and plug up the Oil pick=up in the pan.

I suggest that you inspect your drain oil for "large"debris...!

If you see debri... you might as well replace the timing chain with a high quality double roller.

 

Assuming you are setting the timing in the traditional manner with an original timing tab and the dampner markings, and the dampner is an original equipment piece........I would for certain make sure the inner and outer halves of the dampner have not "slipped." Olds dampners are known for slipping when the rubber bonding material ages and deteriorates. Check that number 1 piston is truly at TDC when the mark is at 0*. I also agree with the reference to the timing chain. If the motor has a lot run time/miles or hard usage, the chain will stretch, possibly slip a tooth if it's bad enough. A combination of both could be a disaster waiting to happen.

 

Seems I remember something about when a carb dumps too much fuel in the intake,it can cause a vapor lock like this when trying to start.Me,455 olds in jetboat-boat that don't start when required is not funny.

 

check your distributor cap for carbontracking, this will cause starter kickback, much worse when it is damp

 

Thanks for the help. I think I will start with TDC check and cap. Then move on to the dollar items. It does have a double roller chain but I drive it hard cause it sure is fun.
High torque starters are $$ so that may be the last item. I did notice a 10.2 volts on the battery which is 4 years old. Not sure if that had anything to do with this but it started happening two yeras ago so I may as well get that out of the way also.

Gary