Author Topic: 1980's valve job vs. 2022 valve job  (Read 382 times)

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1968galaxie

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1980's valve job vs. 2022 valve job
« on: May 02, 2022, 03:04:50 PM »
Bringing back to life my old 390FE.
C1AE-A heads with rudimentary porting job (by me) and a local shop valve job.
30 degree seats - very little bottom cut (60 degree) and 30 degree seat and 15 to 20? degree top cut.

Looking to decide if the heads are worth using. 2.09" intake 1.65 exhaust used (std 3/8" stem)

Changed to a 5 angle valve job 72.5/60/45 seat/37.5/25

Lift      OLD 30deg VJ    new 45 deg VJ

0.100        80.3                 69.7  (- 10.6)
0.200       130.0               146.4 (+16.4)
0.300       175.9               213.4 (+37.5)
0.400       216.9               247.4 (+30.5)
0.500       236.2               258.5 (+22.3)
0.600       247.3               263.0 (+15.7)

The 30 degree seat valve job was not very good (looked almost like a single angle)
The 45 degree seat cuts left plenty for a final valve job.
Some work needed at short turn area and dog leg smoothing. More area over the short turn should help 0.500" plus lift flow.

After seeing flow results of my old 390 heads I was very not impressed.
But after cutting in a modern valve job there looks to be some promise.
New valves and porting ahead.

Seat cut and flow testing at a great Ford FE/SBF/BBF/351C/Flathead shop in southern Alberta - KCR Engine Dynamics
« Last Edit: May 03, 2022, 09:15:20 PM by 1968galaxie »