I think he is probably just going to use the Curtis Sparks X-6 system with either a 426 or 440 kit. Someone told him that was one of the best systems, and the guy that told him knows his stuff.

 

I am new to this but have some friends that own some of the top shops and they said to go with the Curtis Sparks system, that is what I am going with.... These people race and win... so lets hope they are correct.

 

which pipe x-4 or x-6

 

the x-4 is more designed for a stock internal motor. the x-6 is better with internals. after seeing both perform, i would get the x-4 if the most you will ever do is put in a drop in cam and a piston. if your going really radical on the cam, piston, or stroke it, i would probably get the x-6.

 

I would go to dirtwheelsmag.com, then click on latest news and like... number 43 i think it is, is a 400ex pipe shootout, they picked the White Brothers E-series for the winner, also a good is the CT Racing, if you like loud pipes, Also one that i dont think they tested is the Sparks Racing x-4 or x-6, if you wanted to pick between the HMF and Sparks, you should go with Sparks.