ran a 4" tube on the stock shortblock, when i went 408 i upped to a twin tube ( 4" )

thanks for comfirming, ill double check this evening when i pull my CAI to be powdercoated

 

No problem. I still have it beaten in my head from my machining days that 1"=25.4mm, so every time I see a conversion guesstimate that doesn't add up I have to chime in

 

That and countless times hammering away at tire size conversions. haha

Thats a great gain from the intake! 500 is so close!

I'm curious what your cam looks like too. Also, how well do those heads flow? How do they compare to a ported 243?