454/502 magnum intake?
12-29-2023 | 08:23 AM
#11
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From: Cape Coral FL
Pretty sure that i read where the OP has purchased a set of "roval" heads. I seriously doubt that the intake will be a restriction and no amount of porting is going to help the situation. Maybe gasket matching the intake ports of the head to the dimension of the intake and maybe cutting the tops of the runners down level with the floor of the upper might help a little.
12-29-2023 | 02:39 PM
#12
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From: Finland
Say why and 🤣 just came from shopping. Going to weld injector bungs and convert this to efi. Wonder if 2x 1000cfm throttle bodies are too much, or should i convert the upper for single 1 barrel?
12-29-2023 | 02:52 PM
#13
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From: Finland
[QUOTE=articfriends;4887711]
Too bad we dont have anyone here In Finland Who does extrude honing, so i tossed the merc manifold idea. Do you remember the merc manifold runner lenght? The weiand i bought measured 8" excluding the plenum.
Isn't there some kind of "science" that determines ideal intake runner lengths? It seems like it has been lightly discussed here at OSO, but I don't recall anyone ever reporting that they arrived at a certain runner length through any type of formula or software. Obviously, cutting down the runner length has worked for many, but I am hesitant to drop off a lower intake with the instructions "just a little off the top".[/QU
Theres a progarm called pipe max that figures out what "harmonic" a intake is happy at using cu inches vs rpms vs runner length (plus takes into account other info). a 454/502 mag intake in stock form is done around 5200/5400, add 10% more cubic inches by making it a 540, its done approx 10% sooner at 4900/5000. shorten effective runner length , you can now raise the peak rpm SLIGHTLY assuming its not restricted by something else like camshaft , etc. Thats why in my comments I mention not wasting time cutting one down and using the stock cam. and again, as "snapmorgan" mentioned and I mentioned earlier, the most bang for the buck is extrude honing, Smitty
Theres a progarm called pipe max that figures out what "harmonic" a intake is happy at using cu inches vs rpms vs runner length (plus takes into account other info). a 454/502 mag intake in stock form is done around 5200/5400, add 10% more cubic inches by making it a 540, its done approx 10% sooner at 4900/5000. shorten effective runner length , you can now raise the peak rpm SLIGHTLY assuming its not restricted by something else like camshaft , etc. Thats why in my comments I mention not wasting time cutting one down and using the stock cam. and again, as "snapmorgan" mentioned and I mentioned earlier, the most bang for the buck is extrude honing, Smitty
12-30-2023 | 04:39 AM
#14
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From: On A Dirt Floor
Isn't there some kind of "science" that determines ideal intake runner lengths? It seems like it has been lightly discussed here at OSO, but I don't recall anyone ever reporting that they arrived at a certain runner length through any type of formula or software. Obviously, cutting down the runner length has worked for many, but I am hesitant to drop off a lower intake with the instructions "just a little off the top".
I have.
Do a search under my name and pipemax. It was for a 502cid engine..
12-30-2023 | 06:42 AM
#15
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From: Finland
12-30-2023 | 08:20 AM
#16
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From: KCMO
I found SB's post from 2021:
Found a 502 with max power 5600rpm I had run into pipemax:
@ 5800 RPM
- Induction System Tuned Lengths = ( Cylinder Head Port + Manifold Runner )
1st Harmonic= 35.485' (usually this Length is never used)
2nd Harmonic= 20.140' (some Sprint Engines and Factory OEM's w/Injectors)
3rd Harmonic= 14.061' (ProStock or Comp SheetMetal Intake)
4th Harmonic= 11.067' (Single-plane Intakes , less Torque)
5th Harmonic= 8.979' (Torque is reduced, even though Tuned Length)
6th Harmonic= 7.554' (Torque is reduced, even though Tuned Length)
7th Harmonic= 6.520' (Torque is greatly reduced, even though Tuned Length)
8th Harmonic= 5.734' (Torque is greatly reduced, even though Tuned Length)
Note> 2nd and 3rd Harmonics typically create the most Peak Torque
4th Harmonic is used to package Induction System underneath Hood
Plenum Runner Minimum Recommended Entry Area = 2.865 to 3.223 Sq.Inch
Plenum Runner Average Recommended Entry Area = 3.294 Sq.Inch
Plenum Runner Maximum Recommended Entry Area = 3.365to 3.981 Sq.Inch
Minimum Plenum Volume CC = 1113.7 [typically for Single-Plane Intakes]
Minimum Plenum Volume CID= 68.0 [typically forSingle-Plane Intakes]
Maximum Plenum Volume CC = 8229.2 [typically for Tunnel Ram Intakes]
Maximum Plenum Volume CID= 502.2 [typically forTunnel Ram Intakes]
SB is offline Report Post
Found a 502 with max power 5600rpm I had run into pipemax:
@ 5800 RPM
- Induction System Tuned Lengths = ( Cylinder Head Port + Manifold Runner )
1st Harmonic= 35.485' (usually this Length is never used)
2nd Harmonic= 20.140' (some Sprint Engines and Factory OEM's w/Injectors)
3rd Harmonic= 14.061' (ProStock or Comp SheetMetal Intake)
4th Harmonic= 11.067' (Single-plane Intakes , less Torque)
5th Harmonic= 8.979' (Torque is reduced, even though Tuned Length)
6th Harmonic= 7.554' (Torque is reduced, even though Tuned Length)
7th Harmonic= 6.520' (Torque is greatly reduced, even though Tuned Length)
8th Harmonic= 5.734' (Torque is greatly reduced, even though Tuned Length)
Note> 2nd and 3rd Harmonics typically create the most Peak Torque
4th Harmonic is used to package Induction System underneath Hood
Plenum Runner Minimum Recommended Entry Area = 2.865 to 3.223 Sq.Inch
Plenum Runner Average Recommended Entry Area = 3.294 Sq.Inch
Plenum Runner Maximum Recommended Entry Area = 3.365to 3.981 Sq.Inch
Minimum Plenum Volume CC = 1113.7 [typically for Single-Plane Intakes]
Minimum Plenum Volume CID= 68.0 [typically forSingle-Plane Intakes]
Maximum Plenum Volume CC = 8229.2 [typically for Tunnel Ram Intakes]
Maximum Plenum Volume CID= 502.2 [typically forTunnel Ram Intakes]
SB is offline Report Post
Last edited by liquidlounge; 12-30-2023 at 08:24 AM.
12-31-2023 | 05:19 AM
#18
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From: Finland
Just measured the runner lenghts, head 5.5"+manifold 8"=13.5". Weiand 1985/5985 intake. Meausured head is gm iron oval, dont have the floteks home yet. floteks have a different intake valve angle, so that may vary a little compared to the gm iron head
