71Scamper
Mopar runs thru my veins!
Does anybody know what the intake runner size is on a factory 340 X head?
X head runner cc?
- Thread starter 71Scamper
- Start date
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Just askin here so don't explode......but why? The volume of the port is meaningless. It's the shape that counts. The Chevy boys got the port size bragging thing started and they don't even know it means nothing. Those ports are probably the same as any other 340/360 large port small block head.
Locomotion
Well-Known Member
These are NHRA/IHRA Stock head blueprint specs. But that doesn't mean that they are accurate as far as how they were actually produced and installed. OEM chambers, for example, can measure 4-8 cc more than the spec! According to these port specs, later heads are legal for use as long as the max volume is maintained when cut for 2.02" valves. Port volumes tend to be bigger with the 2.02" valve because of the cut required in the bowl area to fit them.
Depending who you talk to, you will get different answers to which head flows better. i.e.: I've been told that the 894 X-head flows a bit better than the later heads with a 2.02" intake valve. But there are too many variables, such as core shift, casting quality, # of valve jobs, different flow benches, etc. that can result in varying volume and air flow numbers. The best way is to check a bunch of heads, equally prepped and on the same flow bench. So these specs are for reference only.
(Don't ask me how the 302 head got on the list with those specs. Racers have gotten a lot of interesting things approved somehow over the years.)
Cylinder Heads:
Casting No.
Intake Volume
Exhaust Volume
2531894 167.0cc 76.0cc 'X' casting
3418915 163.0cc 76.0cc Large valve 2.02" intake.
3671587 162.0cc 72.0cc
3769974 158.0cc 68.0cc
4027596 160.0cc 68.0cc
4071051 162.0cc 72.0cc Engines with 2.02" intake valve have 168 intake cc's
4323302 162.0cc 70.0cc
4448308 162.0cc 70.0cc
4772576 162.0cc 70.0cc
Depending who you talk to, you will get different answers to which head flows better. i.e.: I've been told that the 894 X-head flows a bit better than the later heads with a 2.02" intake valve. But there are too many variables, such as core shift, casting quality, # of valve jobs, different flow benches, etc. that can result in varying volume and air flow numbers. The best way is to check a bunch of heads, equally prepped and on the same flow bench. So these specs are for reference only.
(Don't ask me how the 302 head got on the list with those specs. Racers have gotten a lot of interesting things approved somehow over the years.)
Cylinder Heads:
Casting No.
Intake Volume
Exhaust Volume
2531894 167.0cc 76.0cc 'X' casting
3418915 163.0cc 76.0cc Large valve 2.02" intake.
3671587 162.0cc 72.0cc
3769974 158.0cc 68.0cc
4027596 160.0cc 68.0cc
4071051 162.0cc 72.0cc Engines with 2.02" intake valve have 168 intake cc's
4323302 162.0cc 70.0cc
4448308 162.0cc 70.0cc
4772576 162.0cc 70.0cc
71Scamper
Mopar runs thru my veins!
Rusty, I would never explode at you, we are buds! I get what your saying but I have disagree. If you have a ton of runner volume on a cylinder that can't ingest the full amount of runner volume potential, then port velocity will be down. My 340 breathes pretty good right now with the factory x heads, but I want to go with a set of aftermarkets that have a better flowing port/runner configuration and for the aluminum. So, i'm trying to match to what I currently have or even slightly larger.
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