289 EMC heads part 4

[Mummert]

Wrapping it up.
https://youtu.be/JJnIZF4b_ag

[BLSTIC]

Thanks for answering my timing question! I wasn't expecting to see AB dyno, but your insight on the shape of the graph was great.

2 degrees of ignition lead requirement removal is a significant change in terms of efficiency and burn speed.

I wonder if I can do something similar on a quenched hemi (for lack of a better term) or a 4v head and get similar results

[Mummert]

If you can get the electrode in a more beneficial spot you could see some gains.

[steve cowan]

I am not a Ford guy but I certainly appreciate the work put in those heads,thank you for sharing information and videos.

[buddy rawls]

very nice, but I have a question. Why did you use one of the best superstock castings? Its allowed 152cc's!!!! the same work could have been done on any of the 289 castings. have you got a tabular listing of the flows. I couldnt see the video plot clearly?

[Mummert]

The Hi Po heads in the video were what the customer wanted to use for his project. During the Engine Masters Challenge we used C5AE 2 barrel 289 castings. It was what the rules mandated. No Factory performance castings were allowed.

.050 33
.100 66
.200 123
.300 175
.400 208
.500 223
.600 232

[Slither]

Nice video series and work!

[Slither]

Do you have the exhaust flow numbers?

[Mummert]

Exhaust flow numbers:

.050 26
.100 53
.200 104
.300 139
.400 163
.500 179
.600 181

[Slither]

So these ended up flowing a little less than the original heads flowed?

[Erland Cox]

Swirl on a 2 valve is nothing positive.
I only means that the short side flows considerably less as the longside with rising lift.
What do the intake ports flow with inverted valves, just the stem through the throat?

Erland

[Mummert]

Valves have a radical effect on trajectory of the plume. Swirl goes crazy high with the valves out, airflow only changes a couple percent. Our Y blocks lose flow when you invert the valves and flow the port wide open.
There is nothing negative with some swirl. Fuel efficiency is better, low speed torque as well. Alot of swirl is not good for sure.
The real problem when you try to get the swirl too low is that run the risk of it reversing and going the other way, and that not good. Swirl is crazy sensitive always moving. Any change a 100rpm or less is no change at all. Heads with "0" swirl will go +/- 50 rpm.
Compression ratio, squish to bore ratio and operating range are good indicators of how much you are or are not looking for.

[Erland Cox]

As swirl reverses usually at 0.25 D it is because of the short side loosing some flow.
A wake appears in the curtain area from the seat and flow only turns at the valve.

Erland

[Mummert]

The main thing that dictates a swirl pattern is bowl depth as well as short turn height in relation to valve diameter. The swirl pattern can be altered by chamber shrouding, valve shape, shortturn stability, valve job etc. Every head design has a minimum swirl it can achieve and your job is to try and keep it at the minimum. If 2000 rpm is the lowest a particular can go at full lift, than you need to keep it down there.

[buddy rawls]

The Hi Po heads in the video were what the customer wanted to use for his project. During the Engine Masters Challenge we used C5AE 2 barrel 289 castings. It was what the rules mandated. No Factory performance castings

I didn’t even notice the heads in the video were hipo heads, I went straight to the flow chart. I thought it was the engine master head. So the the question gets even more valid. Except no longer why use the best 289 SS casting (rendering it illegal for any future SS build), to using the most expensive and valuable 289 castings, aside from a TA head. Why not go with any early head? Achieving equal results.

But, as it turns out, the owner contacted me to talk cars, Cobras actually. He is going for very very specific application, a near exact duplication of a Shelby Race motor, circa 63-65. He’s using all the original upper end components in as near Shelby modified condition as possible, including the Weber carb set up. Very nice.