HP loss with dented headers

 

4.25" x 3.75" = 400 ci

 

in-line valve arrangemnent

 

the cam isheavily biased to the exhaust side, could be the reason they didn't see the results everybody expected. back when i was a kid the cams were all intake biased, I'm really curious what engine/application triggered the change to the Ex bias? smaller tighter engine compartments dictating exhaust port exit angle might be a big part of it but i think the pendulum went a little too far

 

but the vid reinforces my belief that headers are ultra over efficient, all but the most exploited max effort builds do very well with moderate sized tubes

 

Johnny was this the same engine they used in the cast log / header swap test? still not a good indicator because they used aftermarket cast manifolds with a short primary runner rather than the worst factory logs that actually come stock. their cast manifold was a shorty header

 

found it https://www.youtube.com/watch?v=Y7_lSU3D0jw

again 221 / 247 crazy exhaust side bias, more than the other cam

 

and another header test https://www.youtube.com/watch?v=rTlHEOE2Zp4