I strongly favor the stock airbox over Pods filters, though I do use the Uni 4055 foam replacement element instead of the paper filter from Honda. Its an economic decision, as the Uni is reusable and the Honda paper one is replace every 6 months, $50 a pop.
There are plenty of pod people on this forum. I'll let them sing their praises. However, beware that you most likely will have to re-jet your carbs to accommodate the loss of carb throat vacuum resulting from pod use.
Having said that, the carb airbox rubbers are getting difficult to find for your bike. They are unique for the 77-78 models, and "used" is the only source. The carb couplers to the intake manifold are also unique to those two years. And, I'm not sure they can be had from Honda, either.
I would expect to rebuild the front brake caliper and master cylinder. These parts can still be had from Honda. Also consider replacing the rubber brake lines with new or better yet, SS braided for a marked improvement.
Do a complete tuneup on the engine. Spark plugs, clean or replace NGK D7EA, Examine points, if pitted, replace. Set the point gap and ignition timing. Adjust tappet clearances, and cam chain tensioner. If you use the stock airbox, clean or replace the engine breather element in the bottom of the filter box.
Check steering head bearings for "notchyness".
Grease swing arm bearings and check for lateral rear wheel movement.
Drain/ replace the fork oil.
Check chain/sprockets for wear, lubrication, and correct tension.
Clean and polish your fuse clip contacts.
Check tires for dry rot/wear, proper inflation.
Check battery electrolyte level.
Check gas tank for internal rust.
Cheers,
