Have a MSD Pro Billet in mine, other than the MSD TFI going T.U. in less than a month I have had no problem with mine. I'm now using a stock Motorcraft TFI with it. Speaking of which, I ordered a TFI Relocation Kit from McCully Racing and wouldn't you know it the fricken US Postal Service delivered it to the wrong address so I am now out the kit and 65 bucks!!