a couple clarifications on the above links...
the Pegasus ducting is really vent ducting for brake cooling or cockpit venting. you want a 2-ply duct whereas the wire reinforcement is sandwiched between the layers. even though Pegasus makes a 2-ply duct, it is lacking compared to the product specs of aircraft ducting.
the aircraft industry has what you want - the CEET rated or equivalvent 2-ply ducting. CEET has better temp/pressure/vacuum operating range than the Pegasus venting duct. I had explored this at one time.
from aircraft spruce, the CEET equivalent is the VENA MTD product. not the VENA MT (single ply) link above from grassdoc - correct company, wrong bookmark. link below.
additionally, aeroduct brand CEET ducting is available from wicks aircraft. link below.
Original FlexFab MAF hose is 16" long ( 15 - 15/16 in, as I measured a NOS one - never flexed)
ORDER 4 FEET AND YOU WILL HAVE THREE STOCK LENGTH HOSES
3" (CEET-12 size) VENA MTD (CEET equivalent) from aircraftspruce is $8.75 per foot. 4" ( CEET-16 size) is $11.50 per foot.
Aeroduct is slightly more expensive than the VENA MTD...
3" (CEET-12 size) AERODUCT from wicksaircraft is $12.24 per foot. 4" ( CEET-16 size) AERODUCT is $13.76 per foot.
images of hose, spec sheets, etc. are found thru the links below. AERODUCT has the wording "AERODUCT" printed on the outside of the hose in a diagonal repeating pattern. see image on product page. the VENA MTD hose has no wording on the outside - just a black hose with white/gray spiral reinforcement on each side of the spiral wire reinforcement about the circumference. see product image.
https://www.aircraftspruce.com/catalog/appages/ceet.php
http://aircraftproducts.wicksaircraft.com/viewitems/aeroduct-hose/aeroduct-ducting
informational overview video I'll post as well:
http://www.eaavideo.org/detail/videos/feature/video/46874087001/ducting:-scat-sceet-cat-ceet
REFERENCE:
posts 17, 18, 20; https://turbobuick.com/threads/stock-intake-tube.460659/