[tekenaar]

Originally Posted by RallyBob I uncovered some more ancient documents yesterday. One of which was a flow comparison test of one of my 1.5 litre big valve heads, and then the effect of placing various intake manifolds on the head to see how much airflow was retricted by the intakes. The results are kind of old (1993) so I don't have any current 'welded/ported' stock intake flow test data, but I did test a bone-stock 1974 intake and then a mildly ported stock intake (I think you have this one in your possession now Gary). I only performed the flow test at .450" valve lift, to simulate a performance street camshaft at peak lift, and no carburetors were bolted to any intakes either, just a radiused (clay) transition was used. *1968 1.5 head, 1.85" Manley valve, street ported, bare port only: 115 cfm *stock 1974 intake manifold: 92 cfm *mild street-ported intake manifold, enlarged for 38 DGAS: 104 cfm *Cannon downdraft intake manifold for Holley 2-bbl: 93.5 cfm *Cannon 'long' DSD intake, 40 mm opening: 100 cfm *Cannon 'long' DSD intake, ported/welded, enlarged to 45 mm: 120 cfm *Irmscher 'short' DSD, 40 mm opening: 110 cfm *Dergo DSD intake, 40 mm opening: 107.5 cfm *Magnoletsi DSD intake, 40 mm opening: 112.5 cfm *TWM intake, 45 mm opening: 114 cfm Hopefully this info will be helpful to someone. Bob

Interesting 40/45 Cannon comparison . . . now you've REALLY got me curious about my Steinmetz 48SSD! Hmmm . . .