You should never run your injectors at more than 80% duty cycleIf you use the stock heads and intake and stay under 250-275 rwhp the 24lb injectors would be fine. If you add aluminum heads, intake and turn up the boost so your in the range of say 300-400 rwhp, I'd jump to 42 lb injectors. That's just me though and I do t like to strain my injectors.