Hey Jase, welcome. Accelerator pump diaphragm is a common failure, so no worry there. As for the vacuum, the hose over to the brake servo could be the culprit, but I'd do the standard stuff: points/condensor/leads and get the valve clearances right ( you need a bent spanner, or to take the carb off to get some of then adjusted ). As all that is pretty cheap, then I'd get it done, then see what gets worse. These motors will go for ever unless you rev the bollocks off an old and worn one!