I had a customer that wanted a set of ported C heads flow tested, these heads were not done by me. At the same time he also brought a set of Edelbrocks that need guides, valves, springs, ported, surfaced and CC set. The C heads had the heat cross over filled and the exhaust divider welded up.


I will post some flow numbers from a vigin small valve G head for reference.

G head tested on a 4.155 bore, @ 28 inches, Intake side, Super Flow 600

.200. 122
.300. 172
.400. 196
.500. 209
.550. 215
.600. 220
.700. 226


Ported C head 2.070 intake valve, 30 degree seat, 4.155 bore, tested @ 28 inches, Super Flow 600

.200. 140
.300. 182
.400. 218
.500. 241
.550. 249
.600 257
.700. 264
.800. 272

Same head exhaust side

.200. 105
.300. 133
.400. 156
.500. 165
.550. 168
.600 173
.700. 175
.800. 182

 

Not yet, but I will be flowing them coming up.

 

These numbers are from a ported F head, Superflow 600 @ 28"
.200 154
.300 202
.400 229
.500 240
.550 251
.600 252
.700 255

 

Thanks, this confirms my suspicions, from your testing and my testing the above C head has weak low lift flow.

 

For those of us not in the know, Do the decimal numbers represent Percent Open of the Valve? Are the trailing numbers CFM?

 

Valve lift and CFM

 

These flow numbers are from the ported G heads, 2.100 intake valve, Vortecpro ported, tested with a 4.155 bore @ 28 inches Super Flow 600.



.200. 158
.300. 213
.400. 251
.500. 270
.550. 274
.600. 275
.700 278
.750. 282

 

Thanks, Kenneth.

 

My D heads, cylinder #3, 2.07 valve, zero port work (they still have the factory casting ridge below the seat). 30* angle. Have a .474 lift cam so didn't go higher than 0.500. Pretty sure this was an SF600 as well, the notes do say 28".

0.100 82
0.200 153
0.300 192
0.400 221
0.500 232

 

Could the C heads poor low lift flow numbers be caused by the porting work performed?

 

[QUOTE=Bernhard;1295969]Could the C heads poor low lift flow numbers be caused by the porting work performed?[/QUOTE

YES, the short turn is very low, a bigger valve would help bring the low lift flow up.

 

Please keep us informed as to what the customer decides to do; fixing the ported Iron C's and making them right, or a full port and complete rebuild/upgrade to the Edelbrocks.

Always excited to see what comes out of your shop, especially when I don't get to come by in person often enough to see all the in-process and completed builds being crated up and shipping out.

 

Thanks, flow testing the Edelbrock heads today.

 

Heres flow test on a Edelbrock 6051 Olds heads unmodified.

Tested @ 28 inches, 4.155 bore Super Flow 600 Intake side

.200 138
.300. 199
.400. 219
.500. 231
.550. 234
.600. 236
.700. 235


Exhaust side

.200. 105
.300. 143
.400. 162
.500. 178
.550. 182
.600. 188
.700. 195

Its interesting to note the valve guides were worn out, and the valve seats were eroded from poor sealing. Your probably not going to get away with bolting these these Edelbrocks on out of the box and getting good service from them. I think Bernard Mondello sells them fully prepped, this would be the way to go if using these heads. Average flow next.

 

Those numbers are from the latest version?

 

[QUOTE=cutlassefi;1296643]Those numbers are from the latest version?[/QUOTE

Casting 6051. I believe there the older version 6051, the short turn looks different from the Edelbrock heads I did for my 455 engine build.