Monogram NASCAR T-bird headers question

[ChrisBcritter]

I'm currently looking for a set of headers for the SOHC engine I'm building; of course there's not much available so I'm thinking of just modifying flanges to make an existing set work. I've noticed these from the 1/24 Monogram NASCAR T-bird:

Can someone tell me how wide these are where I marked on the photo? Thanks! (And if you have a better suggestion, let me know - the engine is going into an AMT '57 Ford chassis with a straight axle setup.)

Edited May 9, 2016 by ChrisBcritter

[Ace-Garageguy]

LH    .65"                               RH     .65"                          (16.5mm)

[ChrisBcritter]

Thanks Bill!