Head Tune-up

Ever wonder what you could do to your heads, while you have them off the engine block, to improve performance a little without breaking the bank account? Here's a few items, just for fun.

Lift Dirty valve Clean valve Unshrouded 3 angle valve Net Gain
.1" 57 61 63 67 +10
.2" 107 112 111 113 +6
.3" 136 136 140 140 +4
.4" 150 150 150 152 +2
.5" 160 160 160 161 +1
.6" 165 165 165 166 +1
AUC 69.25 70.15 70.65 71.6 +2.35
CFMs Calculated to 28" of Water

The first flow test was taken with a dirty stock intake valve
and was tested in a stock E7TE intake port. The results are
listed under the column labeled 'Dirty Valve'.

The valve was cleaned up a little and retested. The results
are under the column labled 'Clean Valve'.

The intake valve was unshrouded. This can be done without
removing the valve if you are careful. See the article
Valve Unshrouding for more on doing this fast and simple
modification. This example removed about .3 CCs from the
combustion chamber. The results are listed under the column
labled 'Unshrouded'

The stock (clean) intake valve is cut in two places.
The results are listed under the column labled '3 Angle Valve'.

Readme.txt The 60 degree cut is not recommended. This will be removed from this section at a future date.


It appears that a little work can certainly spruce up the low lift numbers a bit. The Valve shrouding may not net any worth while results without further modifications because of the slight compression ratio reduction that will occur.

More good stuff!