75HP shot is safe.
An SVT can take a 100HP, but why push it.
Two things you'll need to run bigger than a 50HP shot;
1) copper plugs, at least 1, preferably 2 steps colder
(NGK TR6's have been working great for me and others)
2) timing retard of a couple degrees, number varies by HP
shot. For a 75HP shot, according to Zex, a 4 degree timing
retard is required.
Whatever kit you do get, start small and work your way to a larger shot. Check your engine as you increase shot size.
And careful, it is addictive.
