4.3 performance non-existant?

[myclone]

You can build up the stock heads installing larger valves and better springs but you have to do alot of port work to make them flow... and they still dont flow that well..

Very true on the old non vortec style heads. In the syclone/typhoon community its been proven that stock 95-up vortecs will out flow fairly significantly ported stock heads from the 87-92 vintage.



IMO dont bother with the old style heads unless you enjoy spending countless hours with a die grinder to get very little flow. The combustion chambers on the old style heads are horrible not to mention detonation prone compared to the vortecs. Vortecs can be picked up for 50-100 bucks in ready to run condition off of egay and with some minor bowl blending can be made to flow a decent amount. Plus you get a better combustion chamber with more quench with the vortecs.

Lemme put it this way...Unported vortecs have been 10.29 in the quarter on a bone stock appearing syclone (3500lbs+AWD) with 27lbs of boost. Stock old style 4.3 heads like the mag wasted its time on will only go that fast if they are in the bed of the previously mentioned syclone.