i would not worry about it, so many have done so more, these are strong, no way a 904 is gona blow up on ya. But if ya go 904 you really should go 39m flat side carbs too to get all the bang for the bark.
2007 Speedmaster and miss it!
2013 T-Bird Storm and Luvin it!
Catching a yellow jacket in your shirt at 70 mph can double your vocabulary
