rebuild back to stock?
first the stock cam may be 268
at .008 but its way over
[email protected] and the exhaust is over 300 and your dynamic compression will reflect that. It only runs like a
[email protected] cam when you get it reved up. Has very low lift for a 215 cam The intake closes even later at .002 and you do not start building compression till the valve is closed.
The intake opens early but the big problem is the exhaust closes really really late which gives a lot of overlap- this is for the EGR effect of dilution of your intake charge
It's not 1968-72 anymore
to duplicate 68-72 gas would be expensive no Cheveron Custom Supreme at the pump
Is this a matching number deal?
if not find some 67 915 heads and work with them, D Dished pistons for 9.5:1 or for
sure use the kb pistons specially designed to work with your open chamber heads
tight quench and the right cam can reduce your egt by 500 degrees with gasoline and 800 with natural gas or propane- I have lots of dyno time on those builds and helped KB design the piston with then chief engineer John Erb.
you are going to need seats and i recommend the premium dura bond sinterted metal ones
you are going to need guides and I'd use conversion guides and use 11/32 stems for a lighter valve which your valve train will love-(unless you are doing marine or a motorhome) even with a lazy stock cam or an old school cam.
If you are going to use a low lift cam think Engle, Crower, Racer Brown
you do not need roller tip rockers
If your intake seats are receeded you can go to an oversize valve
the stock stem 2.14 or long stem chevy valves in 11/32
either way you want the valve job to open up the seats and at least hand blend the bottoms- no need for a larger exhaust but ask PRH unless you are not doing seats then the 1.81 exhaust works to give you a new seat
OMG been doing these for 60 years
cut your guides for viton seals
