Re: Big Block Cam LSA Thread
[Re: hudsonhornet7x]
#2871237
01/08/21 05:36 PM
01/08/21 05:36 PM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
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So. Burlington, Vt.
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If you know someone who responded to that thread, just search/view their posts.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Big Block Cam LSA Thread
[Re: hudsonhornet7x]
#2871270
01/08/21 06:29 PM
01/08/21 06:29 PM
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Joined: Aug 2011
Posts: 2,869 Pattison Texas
CSK
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master
Joined: Aug 2011
Posts: 2,869
Pattison Texas
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LSA is just a byproduct of having the correct opening & closing points that YOUR engine & combo runs the best . there is A LOT more to it than just looking at the LSA of a cam
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: Big Block Cam LSA Thread
[Re: DrCharles]
#2871380
01/08/21 10:04 PM
01/08/21 10:04 PM
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Joined: Jan 2003
Posts: 31,052 Oregon
AndyF
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I Win
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Posts: 31,052
Oregon
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What's "narrow" to you? My Mini-Express is 107, in at 2 deg advanced. That isn't narrow. I used to have an old super stock cam that was 102 and a buddy had a cam that was 99. They used to tighten up those lobes a bunch back in the day. Maybe someone still does.
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Re: Big Block Cam LSA Thread
[Re: AndyF]
#2871421
01/08/21 11:50 PM
01/08/21 11:50 PM
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Joined: Aug 2003
Posts: 43,251 Bend,OR USA
Cab_Burge
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I Win
Joined: Aug 2003
Posts: 43,251
Bend,OR USA
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I've ran and raced and dyno tune a bunch BB Mopar wedge motors with stock 440 size heads and narrow, tighter than 106 LSA, that all outran the other cars with similar parts with wider LSA and sometimes more lift and duration and than I had I had one Reed Cam(solid flat tappet grind) that was suppose to been ground on a 104 LSA that was actually ground on a 101 LSA, I ended up installing it at 99 ATDC on the intake lobes and that rascal made the most HP and torque than many other cams with real similar lift and duration with wider LSA 108 ,110, 112 that I had used and tested The customer loved it saying it never quit pulling even above 7500 RPM Stock stroke 440 pump gas motor with a 850 CFM D.P. carb on a Eddy RPM intake and 906 heads
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Big Block Cam LSA Thread
[Re: CSK]
#2871475
01/09/21 08:09 AM
01/09/21 08:09 AM
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Joined: Nov 2011
Posts: 288 PA
Harry's Taxi 2
enthusiast
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enthusiast
Joined: Nov 2011
Posts: 288
PA
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LSA is just a byproduct of having the correct opening & closing points that YOUR engine & combo runs the best . there is A LOT more to it than just looking at the LSA of a cam Wouldn't trying different LSA's be a way of determining what opening and closing points YOUR engine combo works best at.
Last edited by Harry's Taxi 2; 01/09/21 08:10 AM.
'86 Maple Grove KOS Mopar low qualifier......true street legal with no power adders.
NOS-used when losing since 1940.
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Re: Big Block Cam LSA Thread
[Re: mopar dave]
#2871571
01/09/21 12:11 PM
01/09/21 12:11 PM
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Joined: Nov 2013
Posts: 712 Southern Alberta
Uberpube
super stock
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super stock
Joined: Nov 2013
Posts: 712
Southern Alberta
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Bullet spec'd it from my info, most cams are ground for cars, or at the other end , towing with low compression ratio, so I though that was the safest way to go. I have lots of cylinder head so I can always go bigger if I need to. They didn't think the valve train was going to be that successful over 5800 rpm so that's the ceiling for the motor.
Last edited by Uberpube; 01/09/21 12:13 PM.
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Re: Big Block Cam LSA Thread
[Re: mopar dave]
#2871604
01/09/21 01:22 PM
01/09/21 01:22 PM
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Joined: Jan 2003
Posts: 10,011 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Probabley the narrowest LSA needed would have been my first stroker. 535 cubes, 906 heads, 2.14 intake valves, probably didn't flow more than 260 cfm. I bet it would have liked a 98 lsa. IMHO since the overlap cycle is often seeing five times the vacuum draw of max intake valve lift, getting the overlap correct and sufficient for the head flow is the most important event. On the other hand my new mustang 5.0 4v has up to 130 lsa. Those 4v heads flow like crazy at low lift/overlap.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Big Block Cam LSA Thread
[Re: gregsdart]
#2871757
01/09/21 04:43 PM
01/09/21 04:43 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
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master
Joined: Oct 2007
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New York
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the overlap cycle is often seeing five times the vacuum draw of max intake valve lift This^^^
Boffin Emeritus
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Re: Big Block Cam LSA Thread
[Re: mopar dave]
#2871887
01/09/21 10:17 PM
01/09/21 10:17 PM
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Joined: Nov 2013
Posts: 712 Southern Alberta
Uberpube
super stock
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super stock
Joined: Nov 2013
Posts: 712
Southern Alberta
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Yeah, i was just curious who at Bullet. I've talked to so many people about all the parts for this build, I can't recall the guys first name.
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Re: Big Block Cam LSA Thread
[Re: dvw]
#2872014
01/10/21 11:14 AM
01/10/21 11:14 AM
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Joined: Jan 2003
Posts: 10,011 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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I Live Here
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LCA is a function of duration and overlap. Increased duration with the same LCA increases overlap. So If a given combination needs more duration then LCA has to widen to maintain the same overlap. Look at the LCA of big duration cams. It will be wider for most applications. Doug Two things that affect the amount of overlap versus duration are head efficiency and compression ratio. An 8/1 compression motor has to clear a lot more dead volume at overlap than a 16/1 motor. Also, as cam duration goes up beyond a certain point, on average the heads will be better and compression higher. I would bet that could be demostrated by looking at some stock class cams. If i am right, they should have a longer overlap period compared to total duration.
Last edited by gregsdart; 01/10/21 11:30 AM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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