Getting back at it again. Assembled my new 7bolt head last night. My machine shop did a little porting in the bowls and blended the valve seats and throats.
Going to be rocking all evo9 valve train (springs, retainers, rockers), 1mm OS SS valves, bronze guides.
The evo8/9 retainers weigh in at 4.0 grams vs the DSM retainer at 13.6 grams
The evo8/9 rockers weigh in at 40.3 grams vs the DSM rockers at 44.0 grams
The evo8/9 springs are a beehive design with so the require less seating pressures to achieve the same RPM. Should do really well vs my old 200K+ miles old 1g valve springs that spec'd out 15lbs of pressure less than another random 1G valve spring laying around. And that was my best spring still, and I still rev the fucker to 8K+ rpm on HKS 272's. LOOOOOOL
But all in all, expecting a more reliable, better running car with a little more linear drivability due to the higher velocity of the 2G head manifold. Also maybe 5whp more top end due to the better flowing head and port work.
New Head:
My 6bolt head, took a beating. A few cracks here and there...but fuck it...i'd rock it still. Already machined for 1mm OS valves. But meh...I wanted to build a 7bolt head.
Old Head:
