Technical Can I just shape and chamfer these Fenton header outlets with a half round file?

Going through my engine, cleaning it up, fixing some minor things, and switching to dual exhaust, and just noticed these outlets are flat, and this one isn’t quite round. I know I can get them pretty close by hand, but how perfect do they need to be? do they need to be machines? Donut seals are pretty flexible, right?


Sent from my iPhone using The H.A.M.B. mobile app

 

I would concentrate on the head pipe sealing area. As long as the head pipe is slightly larger than the manifold you are good. Don't want the pipe smaller than the manifold. Making it round might make you feel better but I doubt you would see 1HP difference.
SPark

 

What he said...
IF...the pipe that bolts to that flange is larger, then some grinding (not filing) MIGHT be in order.
IF the casting is thick enough..!

Mike

 

If you port-match, you will likely pick up 0.0067hp!

But seriously, if this is a 216, 236, or 261, switching to a dual exhaust system is likely to cause you to lose power (by defeating proper scavenging), not gain, so don't obsess over slight port mismatch.

 

The key is to find thirty ways to find one horsepower.
That's why some builders always make more power.

 

Yes, file it so its slightly bigger than the port..

 

I would. Set a gasket on it and scribe a line so you can make it round. It doesn't need to be out to the gasket line. I've even used those small sanding wheels to knock of some of the roughness of the casting on them.

 

you would never know if you didn't make before and after dyno pulls

 

???
I just don’t want it to leak. I’m not trying to scrape power!


Sent from my iPhone using The H.A.M.B. mobile app