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Re: Lucas Octane Booster
[Re: cjskotni]
#1853140
06/20/15 12:38 PM
06/20/15 12:38 PM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
OP
pro stock
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OP
pro stock
Joined: Jul 2007
Posts: 1,526
North Carolina
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Without looking up the card the engine machine shop gave me here is what I have: 1973 400 with 440Source 499 (4.15") stroker kit - block decked .010" flat pistons, 4.375" bore (35 over) Eddy RPM aluminum heads 88cc chambers Fel Pro .055" head gaskets Comp cams 21-223-4 Base timing is 16*, total is 34* According to the calculator, my dynamic compression ratio is 8.51:1. I need to increase the ABDC number to get my DCR down a bit. Would this be a cam "the range" that would get me down where I need to be for pump premium but also leave me a docile motor that pulls enough vacuum to operate the HVAC box and power brakes consistently? http://www.summitracing.com/parts/cca-23-711-9/overview/make/dodgeOr something like this: http://www.lunatipower.com/Product.aspx?id=4644&gid=365Using my very limited cam knowledge this computes to a ABDC value of 66 (Comp Cam) which drops my DCR to 8.13:1 which might give me a better margin with the pump gas? However would this be too much cam for my needs and drivetrain? I am not necessarily going to go for this exact cam but something close to these specs...
Last edited by cjskotni; 06/20/15 01:29 PM.
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Re: Lucas Octane Booster
[Re: cjskotni]
#1853594
06/21/15 01:12 AM
06/21/15 01:12 AM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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Why not put an adjustable vacuum can on it and dial back the amount of the vacuum advance??? If such a part truly exists, provide a part number and source and I would surely order it. All I know that you can adjust is when the vacuum advance comes in but not how much as that's controlled by the arm itself. JB weld strip(s) of feeler gauge on the back side of the can to limit the arms' travel into the case by shortening the notch. Piece o cake
live every 24 hour block of time like it's your last day on earth
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Re: Lucas Octane Booster
[Re: cjskotni]
#1853605
06/21/15 01:34 AM
06/21/15 01:34 AM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Or find the can with the least amount of advance and file it to adjust, if needed.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: Lucas Octane Booster
[Re: Golden-Arm]
#1853942
06/21/15 07:22 PM
06/21/15 07:22 PM
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Joined: Jan 2003
Posts: 3,623
Millinocket, Maine
JonC
master
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master
Joined: Jan 2003
Posts: 3,623
Millinocket, Maine
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i get 100 octane avgas from my local airport, for (current price) $4.45 per gallon. grab a tank of that, and see how you do. avgas is a hell of a lot cheaper than race gas is.  Airport is 10 mi away,been running it since 1992 !! mine is 1/2 mile away, and even has "pay at the pump". been using it since 2000.  Same here, since '94. Two gallons of Avgas (100LL)to a tank does it for me.
11B40
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Re: Lucas Octane Booster
[Re: cjskotni]
#1854967
06/23/15 02:36 AM
06/23/15 02:36 AM
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Joined: Jan 2003
Posts: 27,467
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,467
So Cal
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Without looking up the card the engine machine shop gave me here is what I have: 1973 400 with 440Source 499 (4.15") stroker kit - block decked .010" flat pistons, 4.375" bore (35 over) Eddy RPM aluminum heads 88cc chambers Fel Pro .055" head gaskets Comp cams 21-223-4 Base timing is 16*, total is 34* According to the calculator, my dynamic compression ratio is 8.51:1. I need to increase the ABDC number to get my DCR down a bit. Would this be a cam "the range" that would get me down where I need to be for pump premium but also leave me a docile motor that pulls enough vacuum to operate the HVAC box and power brakes consistently? http://www.summitracing.com/parts/cca-23-711-9/overview/make/dodgeOr something like this: http://www.lunatipower.com/Product.aspx?id=4644&gid=365Using my very limited cam knowledge this computes to a ABDC value of 66 (Comp Cam) which drops my DCR to 8.13:1 which might give me a better margin with the pump gas? However would this be too much cam for my needs and drivetrain? I am not necessarily going to go for this exact cam but something close to these specs... So no opinions on the cam's I threw out there? I see Lunati has roller cam/lifter sets for around $750 which is pretty dern cheap. Are these any good for a street (no more than 5500-6000RPMs) motor?
The super fat head gaskets are like $300 bucks a set. I think I'd rather save the $$ towards the new cam/rollers tbh. I know I can get the motor to run on 93 pump gas without having to sacrifice timing or compression. What is your exhaust system specs to work with? Headers (specs), manifolds, HP manifolds? What specific carb and intake manifold do you have to work with? What gear ratio and torque converter do you have? You have had success with this flat tappet cam and not had it go flat. So how about saving a bunch of money and sticking with a hydraulic flat tappet?
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Re: Lucas Octane Booster
[Re: autoxcuda]
#1855006
06/23/15 08:50 AM
06/23/15 08:50 AM
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Joined: Jul 2007
Posts: 1,526
North Carolina
cjskotni
OP
pro stock
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OP
pro stock
Joined: Jul 2007
Posts: 1,526
North Carolina
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What is your exhaust system specs to work with? Headers (specs), manifolds, HP manifolds?
What specific carb and intake manifold do you have to work with?
What gear ratio and torque converter do you have?
You have had success with this flat tappet cam and not had it go flat. So how about saving a bunch of money and sticking with a hydraulic flat tappet? I have Hedman headers with 1-3/4" primaries (may upgrade later), 3" exhaust down to the tips. I have a Holley 4150 870cfm vac secondaries, MP single plane aluminum intake. TC is a TCI 2400 stall (may upgrade later), rear gear is 3.55 sure grip. The reason I don't want to re-invest in a flat tappet is the worries about break-in and modern oils. I also know you can get much more aggressive grinds with a roller than a flat tappet (i.e. more lift with same duration). If I am going to take the time to go into this motor, I'd like to make it the last time and not have another "I wish I has done this...."
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Re: Lucas Octane Booster
[Re: cjskotni]
#1855705
06/24/15 01:52 AM
06/24/15 01:52 AM
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Joined: Jul 2014
Posts: 81
Alberta
NEVjr
member
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member
Joined: Jul 2014
Posts: 81
Alberta
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You have had success with this flat tappet cam and not had it go flat. So how about saving a bunch of money and sticking with a hydraulic flat tappet? The reason I don't want to re-invest in a flat tappet is the worries about break-in and modern oils. You have had success with this flat tappet cam and not had it go flat. So how about saving a bunch of money and sticking with a hydraulic flat tappet? you want to keep the power level you have now and stop it detonating, while keeping it docile at idle. you are looking to put several hundred dollars worth of cam into it. the cheaper solution that i can see is to swap head gaskets, do a bit of porting on the head while its off to pick up a bit of flow, and you are out $300 and your time. the next cheapest is to get water/methanol injection, should stop your ping and add some power, not difficult to do, junkyard would have %95 of the parts you need, biggest cost is the added consumable over time. if you are really looking for an excuse to swap cams or a reason to get a lumpier idle, by all means, but dont imagine it to be a good solution to your compression problem.
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