318 head porting for the average joe
Obviously any port is a balanced 'flow path' from carb to valve.
All Mopar heads have a pinch point for the pushrods etc.
So any port must transfer a rectangular orifice to a circular one.
CSA should remain somewhat constant throughout the flow path.
When doing modern heads with 4 valve set-ups, we tended to go for a slight 'funnel effect'.
Much easier with a straight port with an approx 45 degree angle around the valve stem.
Most 'old iron' heads are more like a 75 degree turn from manifold face to valve stem at 15 degrees?
The biggest restriction being the valve guide boss and here is where the 'action happens'.
We just need to know what is 'OK' and what is TOO much?
I have done many hours on 'J heads' and like the early 318 'closed chamber' head even more!
Good luck to all 318/273 head porters, as the Big-Block 'era' is over (for me anyways) lol.
LESS IS MORE...
Obviously any port is a balanced 'flow path' from carb to valve.
All Mopar heads have a pinch point for the pushrods etc.
So any port must transfer a rectangular orifice to a circular one.
CSA should remain somewhat constant throughout the flow path.
When doing modern heads with 4 valve set-ups, we tended to go for a slight 'funnel effect'.
Much easier with a straight port with an approx 45 degree angle around the valve stem.
Most 'old iron' heads are more like a 75 degree turn from manifold face to valve stem at 15 degrees?
The biggest restriction being the valve guide boss and here is where the 'action happens'.
We just need to know what is 'OK' and what is TOO much?
I have done many hours on 'J heads' and like the early 318 'closed chamber' head even more!
Good luck to all 318/273 head porters, as the Big-Block 'era' is over (for me anyways) lol.
LESS IS MORE...