Don Terrill’s Speed-Talk

Man this a tough crowd, try a different view

https://youtu.be/ohzhPa3_97Y

Part 3

https://www.youtube.com/watch?v=BP4sF1LwNGw

Its right at 195-200 cfm. You are right about where I was when I started looking into other heads. Having ported plenty of heads I knew 240-250 was very common for a well ported 1.94". The later casting was 228cfm out of the box. With some bowl work and attention payed to the head bolt side of ...

Everybody has their thing. I've only had 1 personal run in with "corkscrew" vortec heads 20 years ago. My 4.3L v6 in my dunebuggy. I used to work at a shop in 99' or so, we had a deal with UPS to rebuild there engines. Couple years later I thought to myself it would be a decent engine and ...

Yep done little with that head. What kind of power do they make compared to late vortec head. Reason I ask is my 4.3 had those. I messed with them wasn't happy and ported late heads with hollow fast burn valves.

That head needs more timing than 25 degrees when run above 5000rpm like its later counterparts. What I'm trying to say is that as the vorticie get more vertical like a tumbling state the chance for fuel seperation in the cylinder goes down. An SBF TFS twisted wedge heads swirls "0" that do...

This was our first attempt at wet flow. We did get much better at it. It became apparent to me that even though there was little wet flow data here there was a good look at the kind direction and intensity that creates swirl. Its more than just an RPM number.
https://youtu.be/l0e4My1Gzi8

More port swirl usually requires more timing. Higher rates of swirl usually indicate more fuel seperation and less inward rush intensity of the air column. That's interesting, Is that a normal situation or only for this example on the chamber you modified? I can't see how your chamber/ cylinder-hea...

More port swirl usually requires more timing. Higher rates of swirl usually indicate more fuel seperation and less inward rush intensity of the air column.

This video isn't really to say that this mod fixes everything. As much as it is to say that all rules cant be bent. I love the swirl meter because is gives an accurate representation to directional changes of the plume. The main thing that causes directional changes is the short turns relationship w...

Raising idle speed helps vacuum.

Yeah I've seen that, anything can be overdone, but its not the first time I've had it help a head.

The top angle seems to be most critical to fuel momentum, i.e. fighting seperation, I think the first 2 angles the fuel encounters from the port are most critical to to fuel shear.

The Aurora was built in England. The engine is probably most related and inspired by the 2.0l pinto than anything. 4.016" bore centers, 8.169" deck height, bore and stroke were slightly different, but nothing that couldn't be overcome if you were gonna go that far. Aurora 4.0l 93mmx73mm 2...