Pick me a cam (most loaded question ever!)
#3060944
07/20/22 01:37 PM
07/20/22 01:37 PM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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496 RB, 9.65:1, 24cc dish, .051 quench distance, Eddie RPM's ported to a bit over 300 cfm. Eddie ProFlo4 XT intake, TTI headers with side dump Boom-Tube exhaust. 1.5 ratio rockers (Comp Pro-Magnums) . 3700#.
Current cam is a Comp solid flat, custom spec'd by Brian at IMM in Indio when I was primarily doing the Silver State stuff.. I don't have the exact specs, but it's about .375 - 380 lobe, .610-ish before lash w/1.6's, .555 measured w/1.5's after lash at the valve. Chevy lobes for the easier ramps. 114° LSA. Current springs are COMP 928's, good to about .630 lift with a solid flat. When the cam was spec'd, I was still running 1.6 rockers and a carb. I melted a Crane Gold during Silver State, so I went to the Pro-Magnums, but they are only made in 1.5.
I want to be at the best compromise between the 2 types or racing I do, and account for the 1.5 rockers The engine made 604/647 with the old cam and rockers and ran low 11's consistently. I think it cold handle a bit more cam to focus on the 4500 - 6000 range. The compression is lower than I want, but there isn't much I can do with the combo as it sets except dropping the gasket thickness down to net .040 quench, but it only gains me 0.19 compression.
Needs to be able to: Silver State Classic Challenge: high speed road stuff, 90 miles at 145 - 165 MPH, 4500 - 5000 RPM 2500 stall tight converter, 2.50 rear gears in a Mopar dimensioned Ford 9" Rocky Mountain Race Week (Drag-n-Drive, 1400 miles in the mountains and plains, 5 tracks) 5000 stall 8" converter, 4.10's in a Dana 60
Last edited by 67Charger; 07/20/22 03:13 PM.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Pick me a cam (most loaded question ever!)
[Re: Jerry]
#3061235
07/21/22 08:46 AM
07/21/22 08:46 AM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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Joined: Jan 2003
Posts: 3,031
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I would love to go roller, but it isn't in the budget. I'm in the middle of building a shop and now an unscheduled block replacement for the 496, hopefully in time for Rocky Mountain Race Week 2.0 in early September. I split #5, 2" crack running parallel to the deck about 1/2" down in the outboard quarter of the cylinder. I'm having a replacement block machined to take my rotating assembly, and figured there's never a better time for a cam swap. A roller would need a cam, lifters, springs, button, and oil pump drive at minimum. Probably about $2k all said and done.
I'm really looking to see if there is much to be gained in the 4500-6000 range by adding lift, duration, or going to a different LSA.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Pick me a cam (most loaded question ever!)
[Re: 67Charger]
#3061250
07/21/22 09:55 AM
07/21/22 09:55 AM
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Joined: Aug 2011
Posts: 2,864 Pattison Texas
CSK
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master
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Pattison Texas
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Whats the duration of the cam in it now ?
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Pick me a cam (most loaded question ever!)
[Re: 67Charger]
#3061270
07/21/22 10:47 AM
07/21/22 10:47 AM
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Joined: Dec 2021
Posts: 1,145 Loudoun County, VA
Brad_Haak
super stock
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super stock
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Posts: 1,145
Loudoun County, VA
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Needs to be able to: --> 2500 stall tight converter, 2.50 rear gears in a Mopar dimensioned Ford 9" --> 5000 stall 8" converter, 4.10's in a Dana 60
So, which one is more important? It can't be "right" for both, only a compromise that's less than ideal for either config.
2021 Challenger 6.4L Scat Pack 1320 100% stock: 1.680, 11.894 at 113.75 (DA 175 ft) weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008] pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: Pick me a cam (most loaded question ever!)
[Re: Brad_Haak]
#3061280
07/21/22 11:17 AM
07/21/22 11:17 AM
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Joined: Jan 2003
Posts: 17,875 S.E. Michigan
ZIPPY
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S.E. Michigan
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Needs to be able to: --> 2500 stall tight converter, 2.50 rear gears in a Mopar dimensioned Ford 9" --> 5000 stall 8" converter, 4.10's in a Dana 60
So, which one is more important? It can't be "right" for both, only a compromise that's less than ideal for either config. I want to be at the best compromise between the 2 types or racing I do
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Re: Pick me a cam (most loaded question ever!)
[Re: ZIPPY]
#3061292
07/21/22 11:44 AM
07/21/22 11:44 AM
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Joined: Dec 2021
Posts: 1,145 Loudoun County, VA
Brad_Haak
super stock
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super stock
Joined: Dec 2021
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Loudoun County, VA
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Compromise... the worst of both worlds. Right up there with "A camel is a horse designed by a committee"
2021 Challenger 6.4L Scat Pack 1320 100% stock: 1.680, 11.894 at 113.75 (DA 175 ft) weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008] pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: Pick me a cam (most loaded question ever!)
[Re: CSK]
#3061295
07/21/22 12:03 PM
07/21/22 12:03 PM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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Whats the duration of the cam in it now ? I "THINK" it is Comp's lobe 6333/6334, which would be: 299°/303° rated duration, 268°/272° @ .050 and .380"/.384" lobe lift. With 1.5's that's .570/.576 at zero lash, matching my .555 measures after lash on the intake. That means it was .608/.614 with 1.6's @ zero lash I'll check the specs when I can get home to the cam tonight. Custom ground, and the lobe #s are on the end.
Last edited by 67Charger; 07/21/22 12:04 PM.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Pick me a cam (most loaded question ever!)
[Re: Cab_Burge]
#3061377
07/21/22 02:45 PM
07/21/22 02:45 PM
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Joined: Aug 2011
Posts: 2,864 Pattison Texas
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I think he needs a very mild lobe, I would get a circle track type lobe for the kind of racing he does.
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Pick me a cam (most loaded question ever!)
[Re: CSK]
#3061414
07/21/22 03:26 PM
07/21/22 03:26 PM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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According to Brian, the reasoning behind the Chevy lobe was the less aggressive valvetrain motion to handle the sustained time at RPM. Not just RPM, loaded RPM. Closer to circle track than road race or autocross.
How much of a difference is there to be had playing with LSA to optimize the 4500-6000 range? I do feel inclined to get back up to the .600 lift line with the 1.5's, but there is a healthy increase in duration that comes along with that. I'd be at 280° @ .050. to get .590".
Mopar Lobes:
#6587: Adv. 289°, 263° @ .050, Lobe lift .404, Lift w/ @ 1.5 .606 #6588: Adv. 293°, 267° @ .050, Lobe lift .411, Lift w/ @ 1.5 .617
Interesting thing I just noticed: My current 6333 with a 1.6 has .608" with 268° @ .050. Almost the same as the Mopar lobes with 1.5's.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Pick me a cam (most loaded question ever!)
[Re: 67Charger]
#3061461
07/21/22 05:39 PM
07/21/22 05:39 PM
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Joined: Aug 2011
Posts: 2,864 Pattison Texas
CSK
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According to Brian, the reasoning behind the Chevy lobe was the less aggressive valvetrain motion to handle the sustained time at RPM. Not just RPM, loaded RPM. Closer to circle track than road race or autocross.
How much of a difference is there to be had playing with LSA to optimize the 4500-6000 range? I do feel inclined to get back up to the .600 lift line with the 1.5's, but there is a healthy increase in duration that comes along with that. I'd be at 280° @ .050. to get .590".
Mopar Lobes:
#6587: Adv. 289°, 263° @ .050, Lobe lift .404, Lift w/ @ 1.5 .606 #6588: Adv. 293°, 267° @ .050, Lobe lift .411, Lift w/ @ 1.5 .617
Interesting thing I just noticed: My current 6333 with a 1.6 has .608" with 268° @ .050. Almost the same as the Mopar lobes with 1.5's. The cam you have has enough duration , but I would look at 106 to108 lsa & keep the mild lobe, it will work !!!!! we always ran 106ish lsa in our Sprint cars for that coming off the corner power band, it will like the tighter lsa
Last edited by csk; 07/21/22 05:40 PM.
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Pick me a cam (most loaded question ever!)
[Re: CSK]
#3061513
07/21/22 09:02 PM
07/21/22 09:02 PM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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lobe 7160 and 7162 on 110°
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Pick me a cam (most loaded question ever!)
[Re: 67Charger]
#3061521
07/21/22 09:53 PM
07/21/22 09:53 PM
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Joined: Aug 2011
Posts: 2,864 Pattison Texas
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lobe 7160 and 7162 on 110° So is this the cam you have ?
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Pick me a cam (most loaded question ever!)
[Re: 67Charger]
#3061799
07/23/22 09:51 AM
07/23/22 09:51 AM
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Joined: Aug 2011
Posts: 2,864 Pattison Texas
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either keep the same lobe you have & ground on 106 lsa or the 7161 & 7163 on a 108 lsa, other than my advice talk to Dwayne Porter, he can also sell you what you need
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Pick me a cam (most loaded question ever!)
[Re: 451Mopar]
#3062351
07/25/22 10:44 AM
07/25/22 10:44 AM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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The Pro-Magnums are bushed with a teflon/composite looking bushing, The Crane golds are not.
NEED a new cam, no. It was, however, picked when I was still running 1.6 ratio rockers. I've lost a fair bit of lift going down to the 1.5's and I would like it back.
I'll be giving Dwayne a call.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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