Opinions on SBC intakes

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maxracesoftware
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Re: Opinions on SBC intakes

Post by maxracesoftware » Fri May 04, 2018 3:55 pm

Scotthatch wrote:
Fri May 04, 2018 11:37 am
If there is a big difference in dyno HP and track then need to look at the car setup ... gear ..converter..... question becomes where is it not right at the track to where it should be ... also loading can change tune ... dyno does not load the same as in the car do may have to adjust the tune
some of what you posted is true ,
however , what MELWAY posted is referring to is like this scenerio :

the Race Car's ET and MPH is slower than it is calculated to Run
or in reverse-engineered = the ET Slip Data Feet incrementals / MPHs do not matchup to the Dyno numbers

its not a Race Car parts combination problem ,
instead its an Intake Port FPS Problem showing up ,
and there's nothing you can change or fix on the RaceCar to make it correlate properly !

the ONLY Fix is to correct the Intake Port CSA FPS speed problem

this CSA FPS Speed problem will show up more in 3-Speed Auto/Converter Cars than 2-Speed Powerglides
and in 4 or 5 Speed Manual/Clutch Race Cars even more !

the Intake Port FPS down the Dragstrip is changing drastically faster than in a 300 or 600 RPM/SEC Dyno Pull ,
especially in 1st Gear , so there's greater "Intake Port Pumping Choke" TQ and HP losses happening down the Dragstrip .

So MELWAY sees AFR245npp Heads make 750hp at 7400 RPM on his Dyno
but it does not accelerate down the Dragstrip or correlate back to 750 HP
the Intake Port CSA is too fast ... its only going to match the Dyno in high-gear towards the end of the Dragstrip
where its way too late in time and distance to correlate back to 750 Dyno HP
... that 434SBC engine is probably off by 20-30+ HP or more from the Dyno , in 1st Gear and early parts of high gear Feet distances

another similar scenerio :
Chrysler 360cid NHRA SuperStocker (371cid Legal cid ) with a maximum Intake Port Volume CC's = 162.0 CC
so you maxout the Intake Port and make it hold about 161.0 cc to make sure it checks out under 162.0 Legal max CC's

at 161.0 CC Int Port CC ( Intake Port CenterLine Length in SS form = 4.94800 inches length )
1.880 Intake Valve OD = can and will Flow 285 CFM @ 28" inches on my Flowbench
or i can make it Flow using another Shape = 255 CFM or 265 CFM with still another Port Shape
all 3 Shapes still hold 161.0 CC Int Port Volume , but Flow test different CFM and have very different local CSA FPS velocities

the 285 CFM Ports on the Dyno or down the Dragstrip does not make any TQ or HP or ET or MPH differences
-vs- the 265 CFM Ports

and a 255 CFM is within a few HP and TQ of the 265 CFM Port shapes

the 285 CFM in 161.0 CCs and thru 4.9480" length is just way too fast to make anymore TQ or HP
and its a "Miracle" it does not actually loose Peak HP and higher RPM HP
... very luckily that Chrysler Chamber and Intake Port shape combo can handle very lean Air Fuel Ratios
whereas the SBC Chevy SS Ports cannot !

255 to 265 CFM Chrysler #308 or #576 casting at 161.0 CC 1.880/1.660 valves can make 561 Peak HP at 6900-7100 RPM
485-487 Peak TQ with 9.459:1 CR + ThermoQuad and run as fast as
9.69 ET 137+ MPH in GT/CA and 9.72 ET in GT/DA

thru the years i've had the very same SuperStock Chrysler Customers back-to-back same Day
Dyno test same 162.0 CC Ports 1.880/1.600 #576 castings from other Head Porters
on the Flowbench ... CFMs were very close to identical on Int and Exh Ports
but Pitot Probe FPS in certain areas were very different !

on the Dyno , the other #576 castings that were too fast , yet Flow tested the same CFMs, were down -20 HP or more at other RPMs ,
yet , down the Dragstrip it runs the ET and MPH like its down -40 HP or more
so that down the Dragstrip with a 3-Speed Auto/Converter in a NHRA Record GT/CA setting Race Car its 2 Tenths and almost 4 MPH slower
( it should have only slowed down maybe 1 Tenth ET and maybe 1.5 MPH , but it slowed down more than the Dyno showed )
and theres nothing you can do to that Race Car to improve its performance any further ,,
the Head's Intake Port too fast FPS making it not correlate back to the Dyno 600 RPM/SEC Tests properly .

its exactly what MELWAY is describing in his Post .

the Intake Port CSA FPS velocity is drastically changing way too fast in an actual Dragstrip Run
causing Flow separation + Air-Fuel separation + Pumping Choke HP loss
that does not show up at 600 or 300 RPM/SEC Dyno Test Rate .
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Re: Opinions on SBC intakes

Post by statsystems » Fri May 04, 2018 4:13 pm

maxracesoftware wrote:
Fri May 04, 2018 3:55 pm
Scotthatch wrote:
Fri May 04, 2018 11:37 am
If there is a big difference in dyno HP and track then need to look at the car setup ... gear ..converter..... question becomes where is it not right at the track to where it should be ... also loading can change tune ... dyno does not load the same as in the car do may have to adjust the tune
some of what you posted is true ,
however , what MELWAY posted is referring to is like this scenerio :

the Race Car's ET and MPH is slower than it is calculated to Run
or in reverse-engineered = the ET Slip Data Feet incrementals / MPHs do not matchup to the Dyno numbers

its not a Race Car parts combination problem ,
instead its an Intake Port FPS Problem showing up ,
and there's nothing you can change or fix on the RaceCar to make it correlate properly !

the ONLY Fix is to correct the Intake Port CSA FPS speed problem

this CSA FPS Speed problem will show up more in 3-Speed Auto/Converter Cars than 2-Speed Powerglides
and in 4 or 5 Speed Manual/Clutch Race Cars even more !

the Intake Port FPS down the Dragstrip is changing drastically faster than in a 300 or 600 RPM/SEC Dyno Pull ,
especially in 1st Gear , so there's greater "Intake Port Pumping Choke" TQ and HP losses happening down the Dragstrip .

So MELWAY sees AFR245npp Heads make 750hp at 7400 RPM on his Dyno
but it does not accelerate down the Dragstrip or correlate back to 750 HP
the Intake Port CSA is too fast ... its only going to match the Dyno in high-gear towards the end of the Dragstrip
where its way too late in time and distance to correlate back to 750 Dyno HP
... that 434SBC engine is probably off by 20-30+ HP or more from the Dyno , in 1st Gear and early parts of high gear Feet distances

another similar scenerio :
Chrysler 360cid NHRA SuperStocker (371cid Legal cid ) with a maximum Intake Port Volume CC's = 162.0 CC
so you maxout the Intake Port and make it hold about 161.0 cc to make sure it checks out under 162.0 Legal max CC's

at 161.0 CC Int Port CC ( Intake Port CenterLine Length in SS form = 4.94800 inches length )
1.880 Intake Valve OD = can and will Flow 285 CFM @ 28" inches on my Flowbench
or i can make it Flow using another Shape = 255 CFM or 265 CFM with still another Port Shape
all 3 Shapes still hold 161.0 CC Int Port Volume , but Flow test different CFM and have very different local CSA FPS velocities

the 285 CFM Ports on the Dyno or down the Dragstrip does not make any TQ or HP or ET or MPH differences
-vs- the 265 CFM Ports

and a 255 CFM is within a few HP and TQ of the 265 CFM Port shapes

the 285 CFM in 161.0 CCs and thru 4.9480" length is just way too fast to make anymore TQ or HP
and its a "Miracle" it does not actually loose Peak HP and higher RPM HP
... very luckily that Chrysler Chamber and Intake Port shape combo can handle very lean Air Fuel Ratios
whereas the SBC Chevy SS Ports cannot !

255 to 265 CFM Chrysler #308 or #576 casting at 161.0 CC 1.880/1.660 valves can make 561 Peak HP at 6900-7100 RPM
485-487 Peak TQ with 9.459:1 CR + ThermoQuad and run as fast as
9.69 ET 137+ MPH in GT/CA and 9.72 ET in GT/DA

thru the years i've had the very same SuperStock Chrysler Customers back-to-back same Day
Dyno test same 162.0 CC Ports 1.880/1.600 #576 castings from other Head Porters
on the Flowbench ... CFMs were very close to identical on Int and Exh Ports
but Pitot Probe FPS in certain areas were very different !

on the Dyno , the other #576 castings that were too fast , yet Flow tested the same CFMs, were down -20 HP or more at other RPMs ,
yet , down the Dragstrip it runs the ET and MPH like its down -40 HP or more
so that down the Dragstrip with a 3-Speed Auto/Converter in a NHRA Record GT/CA setting Race Car its 2 Tenths and almost 4 MPH slower
( it should have only slowed down maybe 1 Tenth ET and maybe 1.5 MPH , but it slowed down more than the Dyno showed )
and theres nothing you can do to that Race Car to improve its performance any further ,,
the Head's Intake Port too fast FPS making it not correlate back to the Dyno 600 RPM/SEC Tests properly .

its exactly what MELWAY is describing in his Post .

the Intake Port CSA FPS velocity is drastically changing way too fast in an actual Dragstrip Run
causing Flow separation + Air-Fuel separation + Pumping Choke HP loss
that does not show up at 600 or 300 RPM/SEC Dyno Test Rate .


THANK YOU LARRY!!!!

I'd love to print this post off, blow it up to poster size and mail it out all over the Internet. Except nobody would get it. Well, few people anyway.

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Re: Opinions on SBC intakes

Post by GARY C » Fri May 04, 2018 4:21 pm

the Intake Port CSA is too fast ... its only going to match the Dyno in high-gear towards the end of the Dragstrip
where its way too late in time and distance to correlate back to 750 Dyno HP
Is this in reference to MPH? What if Port CSA is to slow wouldn't it still cause an acceleration problem at the track?

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Re: Opinions on SBC intakes

Post by maxracesoftware » Fri May 04, 2018 4:40 pm

GARY C wrote:
Fri May 04, 2018 4:21 pm
the Intake Port CSA is too fast ... its only going to match the Dyno in high-gear towards the end of the Dragstrip
where its way too late in time and distance to correlate back to 750 Dyno HP
Is this in reference to MPH? What if Port CSA is to slow wouldn't it still cause an acceleration problem at the track?
Yes .. if its either way too slow , or way too fast .... it can have very similar effects

here's another CSA FPS potential HP Pumping Choke problem :
if the Pushrod Pinch CSA is way too fast , it has the very same effect as if you lost Total Induction Length ,
in other words , it directly change how your engine perceives the Total Induction length ,
and now what happens is its looks way Shorter Length that does not matchup to your real Total Induction Tuned Length
the major Ram effect is now out-of-phase at the Intake Valve Closing ABDC point

likewise you can have (2) CSA FPS problem combination =>
1= at the Pushrod Pinch
2= at the Floor's Apex and Short Turn Curve

so you combine 1 and 2 = has equaled a 105 HP loss at 7500 RPM ( out of 575 Peak HP ) on a Chevy SS/IA record setting Car chassis and Engine
in back-to-back Dyno same Day testing with 2 different pairs of same #041X Heads 1.940/1.500 Valve Combo
identical Port Volume CC's and Flow Numbers ... but very different local area FPS velocities

one pair #041X Heads SS/IA sets NHRA Record at 10.132 ET
the other pair #041X Heads SS/IA runs 10.80's ET :evil:
yet they have identical Port CC's and Flow numbers
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Re: Opinions on SBC intakes

Post by maxracesoftware » Fri May 04, 2018 7:30 pm

October 11 2013 12:56:33 PM
OCT11012.SFD
Dyno Test# 12 with old Edelbrock #2970 Super Victor ( maxed-out Welded Spacer into Manifold )
Peak TQ= 578.1 at 6500
Peak HP= 815.8 at 8200<<---- this is with only 322 CFM @ 28" inches ( made 807 Peak HP with 317 CFM before Oct 11, 2013 )

317 to 325 CFM ... is all you need to make 800+ HP at 8000 to 8300 Peak HP RPM Range
that will run low 8.30 to 8.40's second ET's at 162+ MPH in 2450 lbs Berretta

Q16 Race Gas + ProSystems Carb + Star Vac-Pump + Jeff Johnston Billet Fab Oil Pan + Dart Pro 1 2.125/1.600 245-246 CC's
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Re: Opinions on SBC intakes

Post by maxracesoftware » Fri May 04, 2018 7:34 pm

Welded Spacer into Edelbrock #2970
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Re: Opinions on SBC intakes

Post by swampbuggy » Fri May 04, 2018 11:18 pm

Some welding on the outside where runners and plenum meet, correct Larry ??? Mark H. :-k

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Re: Opinions on SBC intakes

Post by maxracesoftware » Fri May 04, 2018 11:39 pm

swampbuggy wrote:
Fri May 04, 2018 11:18 pm
Some welding on the outside where runners and plenum meet, correct Larry ??? Mark H. :-k
yes i've welded in a 1 inch Moroso open hole Dominator spacer ontop the #2970 Manifold

??? its possible i might have even welded in (2) 1" inch open spacers ??? i can't remember :)
you can notice some imperfection tiny pot marks from not TIG'ing well enough ontop the Runner Pairs .

and look closer at just below "Heads" i wrote on the Manifold
#2970 out-the-box has a huge ditch or depression between the 2 Port Pair Runners
i also welded that area completely flush .

this Pic next was a brand new Edelbrock Super Victor #???? not sure , it was newer Manifold than #2970
Peak TQ = 576.4 at 6400 RPM
Peak HP = 808.4 at 8100 RPM ( Rough-Carbide Finish )
COLUMN AVERAGES
Test: OCT11010
Corrected Torque and HorsePower
Range: 6200 RPM - 8300 RPM
EngSpd: 7250 RPM
STPTrq: 551.4 Clb-ft
STPPwr: 758.6 CHp
BSFC : 0.523 lb/hph
Fuel A: 181.1 lb/hr
Fuel B: 179.7 lb/hr
Oil P : 79.1 psig
WtrOut: 125 degF
ManPrs: -16.8 inHg
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Re: Opinions on SBC intakes

Post by MELWAY » Sat May 05, 2018 12:41 am

Wow. I reckon there is some material taken out of the roof on those pro 1 😎

Exactly what Larry is saying I have seen with some Sportman 2 iron heads I have ported compared to AFR stuff
My Sportman heads end up about 225cc with over 2.6sq" at pushrod. They only just flow 300cfm. But on various engines I have made more power that what the flow numbers calculate and several car all show the power on track to the dyno
I have had more success with AFR 227 heads on smaller engines. Than the 245 on 430+" engines
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Re: Opinions on SBC intakes

Post by maxracesoftware » Sat May 05, 2018 1:09 am

MELWAY wrote:
Sat May 05, 2018 12:41 am
Wow. I reckon there is some material taken out of the roof on those pro 1 😎

Exactly what Larry is saying I have seen with some Sportman 2 iron heads I have ported compared to AFR stuff
My Sportman heads end up about 225cc with over 2.6sq" at pushrod. They only just flow 300cfm. But on various engines I have made more power that what the flow numbers calculate and several car all show the power on track to the dyno
I have had more success with AFR 227 heads on smaller engines. Than the 245 on 430+" engines
Wow. I reckon there is some material taken out of the roof on those pro 1
... yes ... that's why i rather not Post the Vertical aluminum template Pics, because it also shows the Floor's Apex shape

still its slighty hogged-out a little FelPro #1206 at the Intake Port ... but its up to the Blue colored outline raised-seal in some places
i guess we could just use a FelPro #1207 out-the-box

the very best learning experience i feel you can get as a Head Porter
is to Port NHRA Legal SuperStock SBC 283,305,327,350 older cast-iron Heads + Chrysler 318,340,360 Heads
these all have Pushrod Pinch + Floor Apex + Short Turn Speed Problems to overcome .
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Re: Opinions on SBC intakes

Post by Walter R. Malik » Sat May 05, 2018 11:00 am

maxracesoftware wrote:
Sat May 05, 2018 1:09 am

the very best learning experience i feel you can get as a Head Porter
is to Port NHRA Legal SuperStock SBC 283,305,327,350 older cast-iron Heads + Chrysler 318,340,360 Heads
these all have Pushrod Pinch + Floor Apex + Short Turn Speed Problems to overcome .

YEP ... you get a whole new outlook on what's important and what helps most for power.
And, I'll throw-in Pontiac as well.
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Re: Opinions on SBC intakes

Post by maxracesoftware » Sat May 05, 2018 1:56 pm

Walter R. Malik wrote:
Sat May 05, 2018 11:00 am
maxracesoftware wrote:
Sat May 05, 2018 1:09 am

the very best learning experience i feel you can get as a Head Porter
is to Port NHRA Legal SuperStock SBC 283,305,327,350 older cast-iron Heads + Chrysler 318,340,360 Heads
these all have Pushrod Pinch + Floor Apex + Short Turn Speed Problems to overcome .

YEP ... you get a whole new outlook on what's important and what helps most for power.
And, I'll throw-in Pontiac as well.
i forgot about Pontiacs
especially the 455cid SuperStock application with older version cast-iron Heads
... its a real Eye-opener ... getting the most HP out of those Heads !!!

Walter , do you have any sort of current Specs on Header Primary Tube and Collector diameters for a Pontiac 455 SuperStocker
you could Post ?? or any 455cid App thats close to what an old Pontiac 455cid SS Engine would use for Headers ?
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Re: Opinions on SBC intakes

Post by Walter R. Malik » Sat May 05, 2018 2:59 pm

maxracesoftware wrote:
Sat May 05, 2018 1:56 pm
Walter R. Malik wrote:
Sat May 05, 2018 11:00 am
maxracesoftware wrote:
Sat May 05, 2018 1:09 am

the very best learning experience i feel you can get as a Head Porter
is to Port NHRA Legal SuperStock SBC 283,305,327,350 older cast-iron Heads + Chrysler 318,340,360 Heads
these all have Pushrod Pinch + Floor Apex + Short Turn Speed Problems to overcome .

YEP ... you get a whole new outlook on what's important and what helps most for power.
And, I'll throw-in Pontiac as well.
i forgot about Pontiacs
especially the 455cid SuperStock application with older version cast-iron Heads
... its a real Eye-opener ... getting the most HP out of those Heads !!!

Walter , do you have any sort of current Specs on Header Primary Tube and Collector diameters for a Pontiac 455 SuperStocker
you could Post ?? or any 455cid App thats close to what an old Pontiac 455cid SS Engine would use for Headers ?
In that application we ended up with a 2 step primary with a big step 1 3/4" to 2".
Maybe a three step header primary of 1 3/4" to 1 7/8" to 2" would have been fine also but, we didn't try headers like that for this engine.
This was not a Super Duty but, a mid 70's regular 455.
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Re: Opinions on SBC intakes

Post by maxracesoftware » Sat May 05, 2018 5:04 pm

In that application we ended up with a 2 step primary with a big step 1 3/4" to 2".
Maybe a three step header primary of 1 3/4" to 1 7/8" to 2" would have been fine also but, we didn't try headers like that for this engine.
This was not a Super Duty but, a mid 70's regular 455.
Thank you very much Walter , for the Header info !

====================================================

a little more Info on Chrysler with either #308 or #576 castings 1.880/1.600 Combo at 161.0 Int Port CC's on a 340cid SS engine

1st Gear RPM/SECOND = 3799 thru 1st Gear until 3330 at 1-2 Shift Point
2nd Gear RPM/SECOND = 1400 thru 2nd Gear until 1137 at 2-3 Shift Point

**** matches the 600 RPM/SECOND Dyno Test Rate near 500 Feet distance ****

478 RPM/SECOND at 660 Feet distance
384 RPM/SECOND at 1000 Feet distance
310 RPM/SECOND at 1320 Feet distance

File Date : September 4 , 1997 ??? not certain this is actual real Date ?
340cid Chrysler ( Louis Smith , Prince Edward Island , Canada )
SS/DA NHRA Record 9.720 ET
Goodyears, 71 ThermoQuad
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Re: Opinions on SBC intakes

Post by swampbuggy » Sun May 06, 2018 11:21 am

Larry, in the picture you posted on Friday May 4th @ 11:39 pm which was of the inside of that plenum you called maxed out, is the TOP part of the longer runner a lot wider (or) is that mostly an illusion ?? Thanks Mark H. :D

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