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#1
03-11-2014, 12:41 PM
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Would the Old Faithful cam on a 114 LSA be down on power from 112 LSA by much?
I was planning on having a Old Faithful cam built on a 114 LSA to make sure I have enough good vacuum for my 79 TA/SE with 4wheel discs. I am putting together the following combo. The OF cam is 236/245 duration with 578/582 lift.
Pontiac 455 .030 10.02 compression Forged I beam rods Tomahawk or RPM intake Holley 850 or 950cfm 1 5/8 headers 4speed Would the OF cam be down on power by much if I had them build it with a 114LSA instead of a 112LSA. What kind of difference would it make with the overall performance of the engine vacuum....wold it increase by much? Would it take away a lot of HP and Torque? |
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#2
03-11-2014, 01:09 PM
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Probably very little noticeable difference from 112 to 114 LSA thought mathematically it would add vacuum and smooth out the idle to some degree.
Think of your power curve as a piece of string of a fixed length - if you increase the LSA the "peak" value will go down and flatten out the curve. Conversely if you were to lower your LSA to say 108 then the peak would be higher but with a more narrow power band.
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1994 Formula 535ci NA CV-1 - single 1050 with c14 - 940hp@7000/825tq@5200 Pontiac Powered 4th Gen Project Progress 
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#3
03-11-2014, 01:19 PM
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Quote:
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Karl 
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#4
03-11-2014, 01:37 PM
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The static compression ratio is a KEY player here. I've built a number of 455's with that cam, and idle quality isn't nearly as good at 10 to 1 compression as it is at 10.5 to 1.
That cam really starts to show a "soggy" idle as the compression gets lowered. Not a big deal at all, unless your combo needs pretty high vacuum and stable idle in and out of gear. I'm curious about the heads used for this build, what are they?....Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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#5
03-11-2014, 01:44 PM
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My Trans Am is equipped with the smaller factory original 9 inch booster as well since it is W72 4speed car. I am not sure how much of a difference that would make?
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#6
03-11-2014, 01:46 PM
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Quote:
I forgot to add that....they are Edelbrock D ports 87cc with no port work or anything. AND Why would idle quality be better at 10.5 to 1? Last edited by Nitebird; 03-11-2014 at 01:51 PM. |
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#7
03-11-2014, 01:48 PM
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Aluminum heads............ I would stick with the 112.
https://sites.google.com/site/ksmsin...nfo-timing-101 Last edited by PONTIAC DUDE; 03-11-2014 at 02:00 PM. |
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#8
03-11-2014, 02:28 PM
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My car has the factory original 9 inch booster that has been rebuilt. Will the smaller booster be a factor in not being able to maintain good vacuum for the 4 wheel disc brakes with that cam?
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#9
03-11-2014, 03:43 PM
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In my 400 stroker (4.25") I am running the OF at a 114 LSA at 10.25:1 (actually 10.3:1) with 309 cfm R/P E-heads, E-RPM, E-carb (for now) 2004R trans with 2200 (in a V6) stall in a ps/pb '68 ragtop. Great vacuum (better than my stock 400) and has a fairly rowdy idle. Dave at SD also suggested I run on a 114 LSA. Engine has only run on a stand thus far. It would be quite interesting to see what a desk dyno would predict. Rumor has it that it took out a bit of the peak torque, but showed pretty good (or better) peak hp and more rpm than the 112 LSA version.
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#10
03-11-2014, 04:09 PM
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Another 400 stroker with 114 LSA Old Faithful. Compression is 10.7:1. I've not been on the dyno yet, but Dave at SD Performance recommended the 114 LSA over the 112.
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1964 Catalina 2+2 4sp, 421 Tri-power 1965 GTO, Roadster Shop chassis, 461, Old Faithful cam, KRE heads 305 CFM, Holley EFI, DIS ignition. 1969 GTO 467, Edelbrock 325 CFM, Terminator EFI 1969 Firebird Convertible |
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#11
03-11-2014, 05:28 PM
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darbikrash,
Would like to see your dyno session results- 114 LSA recommended due to EFI? 1.65 rockers? You might see 575 hp (at a few higher revs than the 112 LSA) with your combo with good carb/ignition tuning. Your set-up is what I would have intially run if I didn't already have the E round ports. I wanted the "sleepier" of the two cams, but the 114 still has a bit of swagger. Some may call the 112/114 LSA discussion "splitting hairs". I call it trying to get the most enjoyment out of your combination for its intended use by this "fine tuning" approach. Hope this helps, Nitebird (but, probably not). 
Last edited by tpssonic; 03-11-2014 at 05:35 PM. |
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#12
03-11-2014, 05:54 PM
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Yes, I think the EFI did influence Dave's recommendation to 114 LSA. I have 1.52 ratio rockers. I do not really need the vacuum signal as I have hydro-boost for the brakes, but for tuning the EFI I wanted to have a stable idle.
He also mentioned that a stroked 400 EFI motor he just did dynoed @ 574 HP with the same heads, lower compression and a 114 LSA OF. I got the impression he was pretty happy with the change to 114 LSA for the Old Faithful cam, and has had some recent success with it. I know I'd be thrilled with 575 HP. I'll post dyno info for mine when available. For the OP, I'd call Dave @ SD Performance and ask him directly if he would still recommend 114 LSA for a carb application.
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1964 Catalina 2+2 4sp, 421 Tri-power 1965 GTO, Roadster Shop chassis, 461, Old Faithful cam, KRE heads 305 CFM, Holley EFI, DIS ignition. 1969 GTO 467, Edelbrock 325 CFM, Terminator EFI 1969 Firebird Convertible |
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#13
03-12-2014, 07:57 AM
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Quote:
474 - 4speed with 9" booster 4 disc SD Performance 290cfm Kaufman heads, 10.3:1 OF spec. cam 1.65 rockers |
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#14
03-12-2014, 02:45 PM
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#15
03-12-2014, 04:13 PM
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My TA with the small 4 WD dual diaphragm booster does good until vacuum is down in the 9-10" range.
Big solid FT cam in a 400 and a single plane intake was the only combination it was a slight problem. Even my 259/264 @ 0.050 soolid roller in a 455 worked great,
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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