Hughes Magnum Air-Gap Install

MRL Performance said
We did one earlier this year, worked out great. This 408 is getting 19-22mpg (city/HWY) and is making around 450HP, or almost 2X that of a stock 318 that it replaced, and it was getting 13-16mpg.

wow thats awesome and i want to do a 426" kit someday! those are numbers i would be perfectly happy with, what heads, compression and cam did you run?