How would a 265 head fair on a 10.5:1 496 with 252°-260° @.050 .598 solid FT in a 4300 lb vehicle? Mostly street but will make a trip or two to track. Would it support 6000-6500 rpm?
Would I be better off with the 305? I really like the looks of the 265 head as far as numbers go. Actually I would be at 10.7:1 with a 114cc chamber. I only have 91 fuel available here.
It would kick azzz if you wanted to place your emphasis on the street side of the street/strip equation and run damn hard at the track as well.
My air dyno has that combo making 625 ft.lbs and 660 HP (a mechanical roller would have been a fair amount stronger). Note you would have a 112 chamber with the CNC chamber version which is what I based my hypothetical power numbers from....that gets you just under 11.0 which is really perfect anyway as far as Im concerned. You have enough cam to bleed off excess cylinder pressure.
In a 3900 lb Chevelle (race weight) with drag radials or the like, that combo would run 10.90's at 126 MPH with a very modest 60 foot time....with slicks or ET streets it would go similar trap speeds and ET in the 10.70's likely.
Of course it would be a hoot to drive on the street with tire shredding torque at practically any RPM....
Go for it....spring for a roller cam if its in the budget. Its worth 25+ HP in this application
Originally Posted by email@example.com
Tony, have the head's been rolled any? I have a couple Dart Intake's that matches the GMPP gasket pn 12366985 perfectly ( which incidently is the only exact fit roval gasket I have seen). Will this gasket be applicable to your port as well or will you have your own gasket? I may be a player for your cnc'd version when it is finished. I ask because the Edelbrock head's I currently have are rolled some.
Heads are 24' just like our current rect port line-up with all the valves and geometry in exactly the same position/location.
A stock GM "roval" gasket will work perfectly btw....we used that gasket to shape and position the leading entrance of the heads....after that its a completely different approach to the valves (compared to the Eddy/GM piece).