Maybe this is the source of some confusion. I have stated several times that I am trying to find the flow limits of a 2.02 valve. But that is not the same as saying I believe more flow is always better. I'm trying to understand what exactly is going on the the port that stops flow at the...
Point taken, but not necessarily agreed with. I do appreciate having my thinking challenged. It's how we learn new things.
Now here's why I say I don't necessarily agree. I am thinking street head which means less overlap. A 50 degree seat will help prevent reversion. A 40 degree top cut...
I have never flown a port backwards. I’m not saying you are wrong, but I heard Darin Morgan say to fight reversion with velocity and cam timing, not seat angles. I do know this. The steeper top cuts fight reversion both on overlap and the short side reversion that occurs at high intake valve...
Here's a few pics. Since the new valve job is not centered on the old seat insert, it's a little confusing to look at since each angled cut goes in and out of epoxy, aluminum and insert. Hopefully the color coding helps identify each cut. Cuts are 40/50/65/75/80 with the 80 blended. The red...
No difference. This is just the first step - move the valve centerlines. I've been trying to find the flow limits of a 2.02 valve, so I want to stay at that size for a while. The exhaust valve was moved more than the intake in the hopes of testing something larger than a 2.08 at some point in...
I’ll post some tomorrow. Seats were not replaced. Epoxy was used to form part of the top angle in the chamber and to form part of the throat. This is one port in a test head.
I sure wish this test were with some PBR prepped heads. The CNC Speedmaster heads seem to be all over the map with quality. The head I have for testing is 200cc, 93% throat and flows 266 cfm.
Here's before and after data from the same port on a stock Speedmaster SBM head, not CNC'd.
Before: OOTB stock 15/45/60/90 valve job with Ferrea 30/45 valve, 90.2% throat. No modifications to port or chamber.
After: Intake valve shifted 0.060", exhaust valve shifted 0.080". Valves sunk...