273ci thoughts?

@66fs & @273 As well as everyone else who were waiting in this..... SORRY FOR MY DELAY.

These are my W5 heads ported by Brett Miller. Brett tested them on a 4.125 bore plate. This engine will have a 4.03 bore size. These are the difference between the flow plates (4.125 & 4.03) and not the tester or the bench. The second tester of my heads has been building race winning engines about as long as I’m alive and his son was a just a few years younger than me, has always been working in the family owned shop. Years back he was schooled by none other than “Joe Mondello.”
Enough said....

........... 4.125………............................4.03...........

Lift —-— In ——exh ——--In —-——Exh————

.100 —-. NA ——————- 60 ——— 57
.200 —-.121 —- .110 —— 115 —- 120.4
.300 —-.180 —- .151 —— 172.4 - 141.8
.400 —- 228 —- 184 —— 230 —-176.9
.500 —- 278 —- 206 —— 275.7 — 188.1
.600 —- 308 —- 218 ——- 294 —- 212
.650 —- 312 —- NA ——— not tested —
.700 —- NA —— 235 ——— 298.6 —- 222

NA = Not Available/Not Tested
I asked Brett about the .650 & .700 oddity.
I’m not remembering 100% correctly here but it was something along the lines that the port went noisy and turbulent. So it was backed down the .050, read, recorded and reported as quite.

My guy said the port got loud at .700. And recorded the number. He also included swirl numbers if anyone is interested.

As talked about before, bore size has an impact on power production despite what anyone says. There nutz to think otherwise.

While there is only a few scant cfm number differences, at a lay mans calculations @ 2 cfm per HP on a honesty nice street machine build, not race territory, which can be much greater, there is a 28 HP difference just in the head flow alone. All due to bore size allowing more cylinder head flow for more air and fuel.

It’s a dam shame 1 of the W5 cylinder heads gave up the ghost and revealed a thin walled port halting anymore porting. It should still make for a good power producing engine though. It fell short for me. A little bit of a disappointment, but not entirely unexpected though fully hoping for better.