NHRA STOCK CLASS DUSTER

As Jeremy said, my Duster runs a Mopar Performance 340 resto block. A rigid block with very good ring seal are essential to getting every bit of power available. Any time a non original part is used, it must be on the approved listing from NHRA, and must be in stock spec. ie, compression, chamber volume, port volume, weight, stroke, bore.

Due to original parts supply drying up some replacements have been allowed, or other part numbers allowed. For example, a 73 low compression 340 would have come with 576 casting 1.88 valve heads, it is legal to use as a replacement several other part numbers, including 308 castings which were made in late 80's and early 90's. These can be used as long as they are to stock spec as far as valve size, port and chamber volume.