PRH
Well-Known Member
Ootb, as in ZERO work with a grinder, non-cnc’d 440-1’s can be as bad as not quite 300cfm on my bench on a 4.375” bore.
They have come with the chambers cnc’d for several years now, but they didn’t always…….. and I’ve tested them prior to them having the chambers done where they didn’t break 300.
Another 440-1 “ism” for the as cast heads is the shape of the floor near the final approach into the bowl is slightly different between the four ports.
Also, how steep/abrupt the bowl cut is where it meets the ssr can result in fairly big differences in the ootb flow.
All that aside, they can all be in the 330+ range with very minimal work.
Imo, you’re not getting a very good return on your investment if you run these heads without some amount of porting/blending.
On my bench, as they come from Indy, cnc-325’s flow around 360 with a 2.19 valve, and the cnc-345’s are usually very close to 380 with a 2.25 valve.
They have come with the chambers cnc’d for several years now, but they didn’t always…….. and I’ve tested them prior to them having the chambers done where they didn’t break 300.
Another 440-1 “ism” for the as cast heads is the shape of the floor near the final approach into the bowl is slightly different between the four ports.
Also, how steep/abrupt the bowl cut is where it meets the ssr can result in fairly big differences in the ootb flow.
All that aside, they can all be in the 330+ range with very minimal work.
Imo, you’re not getting a very good return on your investment if you run these heads without some amount of porting/blending.
On my bench, as they come from Indy, cnc-325’s flow around 360 with a 2.19 valve, and the cnc-345’s are usually very close to 380 with a 2.25 valve.
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