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Given stock ZZ4 (L98) heads are 58cc chamber/165cc runners, would the Summit Alum head #162109 be a good upgrade ?
It has 62 cc chambers so you give up a little CR but the flow numbers are so much better from .2-.4 !
Hard to find too many alum aftermarket heads with chambers this small.
Not sure what your goals are, but I swapped out the cam in my ZZ4 to GM's "LT4 Hot Cam" along with switching to 1.6 rockers and Manley springs & Race Flow valves, and added a Moroso stud girdle. Did some light porting to smooth up the ports on the ZZ4 heads removing machining steps, casting flash, etc. Just thought I would through this option out there as an alternative to buying all new heads.
The valves increased the flow considerably in the .1-.3 lift range over the original GM valves due to the reduced stem and shape of the valve itself. I measured it on a flow bench years ago, but since have lost the numbers. I just recall it was quite a boost in flow at the lower lifts. Car runs in the 12's now.
10-18-2018, 04:04 PM
What heads would be good ZZ4 head upgrades
