I was looking for my next upgrade and contemplated porting a VC460, GX390, and/or Predator 420 head. I ended up watching a LOT of videos and took the plunge on mildly porting my VC460 head as well as installed 1.3:1 roller rockers. Off the line start it launches much harder, ~250 more RPM at WOT and +5 more MPH. I installed a VC timing key at 6 degrees advance prior to this last change and it sometimes kicked back while pull starting it and that hurt. Now it does not seem to do that, so I am contributing this to the 1.3:1 rockers since the valve end gap is the same both with the 1.1:1 and the new roller rockers.
This video of all of them I thought was really good for a high level overview on porting heads.
This video of all of them I thought was really good for a high level overview on porting heads.
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