Bob Perkins
November 24, 2014

Boss Exhaust

I have a ’70 Boss 302 exhaust H-pipe that I bought back in the early ’90s as N.O.S Ford. There is no Ford service sticker left on it, but I can see remains of a label of some sort. How can I determine if it’s a real Ford H-pipe? There is a bit of surface rust on the pipe that makes it hard to find any markings.

Bob Pope
Rocky Mount, NC

I have included a few pictures to highlight the Ford engineering number, the stop tabs, and the Ford Oval stamped in the tube of an original Boss 302 exhaust H-pipe. Original Ford pipes are double-wall thickness and weigh about one-third more than a re-pop H-pipe. An original will have the above listed features. Aftermarket H-pipes from the ’70s, like Arvin, are very similar to the OEM Ford without the Ford engineering number and Ford oval on the tube. Arvin was the OEM supplier to Ford. If your H-pipe is a Genuine Ford you have a rare find!

1970 Gas Cap Fitment

Do you know how you can tell the difference between a ’70 gas cap with the evaporative emissions system and a cap without the evaporative emissions system? Is there a difference on the back, etc.? Thanks!

Luke Lucroy
Baltimore, MD

A ’70 Mustang gas tank filler neck is unique on a car equipped with the evaporative emissions system. The ’70 gas cap for an evaporative emissions equipped car is Ford PN D0ZZ-9030-A. The front portion of the cap is the same as a standard ’69-’70 gas cap. The back portion, which is riveted through the front portion, has a longer neck to accommodate the special gas tank filler neck. I have provided a picture of both caps side-by-side. You can see the deeper neck (pointed at with ball-point pen) in the picture as the gas cap on the left.

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Send your restoration questions to: Resto Roundup, c/o Bob Perkins, Perkins Restoration, North 2123 Hwy. 16 & 26, Juneau, WI 53039. Send email to