Good quench or adequate quench depends on what factory head you’re talking about.
The heads up to 66 and the B body heads up to mid 67 had the most quench area.
These where not the greatest in terms of unburned fuel emissions, but they had better tolerance for octane level for a given compression ratio.
The 1967 670 and RA997 casting gave up some of that quench area.
The 061 casting of late 67 I call the mule head because it was used by the factory to see how far they could go with an open chamber and still not have a head that was prone to detonating.
The good thing about these 061 castings and there shallow chambers is they have about .040” more short turn height to them so when porting them to flow intake flow levels above 260 cfm it’s easier to keep them from breaking into a tumble condition and going into flow regression.
The 68 and up chambers with there increased quench are over the 061 casting shows that they found out which direction they needed to go to have control of emissions, a good burn rate and a unshrouded chamber.
Where talking non RAII ( 1968 1/2 ) D port heads only.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
Last edited by steve25; 12-13-2025 at 09:25 AM.
|