How much hp/w2

B3422w5 said

I think the 640 ish number someone posted above is a pretty fair number for a W2 head and a single 4 cast intake.
I know of a W5 single 4 cast intake motor that made 700, and proved it at the track. That is the highwater mark i am aware of regards actual track results for either set of heads W2/ W5.
To me a dyno can say anything. But getting it on a track tells the real tale. Weight/ MPH

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I made over 700 with W5 heads but it took a tunnel ram and alcohol to do it. Again, had I had to do it again, I could have made more knowing what I know now. It would take more welding and I'd damn sure use a smaller exhaust valve. Would even do that with a W2 head. Should have mentioned that earlier. I would not have used a 2.100 valve either. No matter how you do it, unless you do way more welding than that head is worth, that port just won't support that big valve.