Hi Solman
You can still get serviceable replacement parts for those engines but I have noticed alot of mower shops are no longer keeping them in stock. Those older Briggs are good engines and easy to work on, as CyberJack mentioned you could change the ignition coil from the old points system to electric. If you have some knowledge on the ignition system you could try and clean the old points and check the gap, the other main problem I find with these old engines not getting a spark is that the main high voltage wire that connects to the spike at the end of the boot doesn't make contact and needs to be re spiked through the rubber insulation making contact with the wire inside the insulated rubber.
As for the blade holder it looks worn out as the holes are supposed to be D shaped so the bolts lock in and don't spin. Blade plate and bolt kit are available as replacement new parts.
Good luck with the restoration hope to see more progress on your project.
Cheers
B_S
