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Author
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Topic: compression & cam help
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Rare67
Journeyman Posts: 16
From: Jefferson. MD
Registered: Mar 2004
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posted 08-20-2004 10:23 PM
   
Several years ago I had my engine rebuilt to the following specs.I was told I had 11:1 compression by milling the heads to give a 60cc chamber, decking the block to 0, and using TRW dome pistons. I have plugged these specs into the online compression calculators and don't come up anywhere near 11:1...which isn't really a bad thing. I'd like to put a smaller cam in to regain the bottom end power, but was afraid of detonation with 11:1. Now that the compression seems to be lower, what cam would you guys recommend? Any other recommendations?
I'm getting away from racing and just want a fun weekend quick ride. Heres the specs: 1967 Mustang Fastback Block: 289 bored .030
stock bottom end all rebuilt and balanced
ARP rod bolts
TRW forged dome pistons (.440 dome notched for plug)
11:1 compression (I think its lower) Heads and Valvetrain: World Products (Dart II) 351 Windsor Sr. (early castings with the odd ��what were they thinking�� plug locations)
Manley 2.02 intake 1.60 exhaust valves (5 angle valve job)
Screw-in studs, guide plates, hardened push rods
Harland Sharp roller rockers
Heads milled (along with the block decked) to give a 60cc chamber
Machined for Fel-Pro loc-wire gaskets Crane solid lift cam: 284/294 (238/248 @ .050) 533/555 lift RPM range 3000-6500 (valve float 6800)
120lbs. Springs
cam set at 106.75 (.032 ahead)
Hamburger timing chain
High volume oil pump, deep pan Induction: Holley 700 DP (4 corner idle circuits, milled choke tower)
Edelbrock Performer RPM intake
Holley mechanical fuel pump Exhaust: Hooker competition headers
2 ��full length exhaust with h-pipe and Dynamax mufflers Ignition: MSD distributor, coil, and 6AL ignition box w/ rev limiter Clutch and Transmission: Hayes steel flywheel
Centerforce clutch
Lakewood blow-proof bellhousing
Stock 4-speed top loader
Hurst shifter Rear: 9��, 31 spline Moser axles, traction lock, 3.50 gears Tires: 16x8 Vintage 45s with 225/50/16 rubber
Tires are just over 24" Go here for a short .mpg of the car at idle:
http://mywebpage.netscape.com/Bubby827/rump-rump.MPG Heres a pic:
http://mywebpage.netscape.com/Bubby827/sunsetsig1.jpg Thanks guys Paul [This message has been edited by Rare67 (edited 08-20-2004).]
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MidLifCrisis
Gearhead Posts: 466
From: Frederick County, MD
Registered: Oct 2001
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posted 08-21-2004 10:05 AM
Paul, that is one great looking car. Do you ever get up to Jimmy Cone in Mt Airy on the 1st & 3rd Saturday nights? As for cam selection, I am no expert, but some of the guys here are. So they can correct me with my suggestion of either the Edelbrock Performer RPM or Compcams HE268H if I am way off. Charlie
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rdinmv
Gearhead Posts: 139
From: orange county CA
Registered: Feb 2004
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posted 08-21-2004 12:24 PM
as long as the compression isn't too high the 268 is a grat cam, I used to run one im my 351w, I'd think the rpm wouldnt give you the low end the 268 will.MY 67 vert http://htwheelz.smugmug.com
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Tea'sGrabber
Gearhead Posts: 276
From: Seattle, Wash.
Registered: Feb 2003
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posted 08-21-2004 12:47 PM
Paul....... we have basically the same shortblock.. only difference is I have Carrilo rods and stock head castings. My pistons are the same except they are Speed-Pro. The catalog show's them @ 10.47 with a 60.4 cc head. That is with the piston .016 down in the hole. So you are pretty close to 11:1 being that you are 0 decked. I'm .007 out of the whole with a 49cc head and real close to 13:1... I'm a 302. That camshaft is a dog... I'd send an e-mail to Alex(MoneyMaker) and see if you can pick his brain. I personally like solid mechanical rollers.... I rrun mine around town all the time..... I have to run race fuel but it's fun!!!!! good luck!!!------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.
http://mustangsandmore.50megs.com/MembersPics/TeasGrabber.html
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n2oMike
Gearhead Posts: 2419
From: Spencer, WV
Registered: Jan 2001
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posted 08-21-2004 06:43 PM
The 114 degree lobe seperation angle is WAY too wide on that cam. What is your intended rev range? How high is the car shifted? Something similar with around a 110 degree lobe seperation will make decent power from around 2500, then pull like Jack the Bear from around 4k to 7k with a good combo. ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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Rare67
Journeyman Posts: 16
From: Jefferson. MD
Registered: Mar 2004
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posted 08-21-2004 09:04 PM
quote:
Originally posted by n2oMike:
What is your intended rev range? How high is the car shifted?
Right now cruise rpm is around 3000...not really into the powerband.
I'd like it to pull in the lower rpm range, and be in the powerband at cruise. I don't need all the power up between 6000-7000. Maybe top out around 6000. I'd like to be able to use 93 octane without it knocking, but if it is around 11.1, my choices are limited...maybe a thicker head gasket would bring it down a bit. How about the Comp 270S, Nostalgia Plus, or the XE274H The car used to have 4.57s and pulled like crazy, but they got old on the street. With the 3.50s it is a dog. Paul
[This message has been edited by Rare67 (edited 08-21-2004).]
[This message has been edited by Rare67 (edited 08-21-2004).] [This message has been edited by Rare67 (edited 08-21-2004).]
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MidLifCrisis
Gearhead Posts: 466
From: Frederick County, MD
Registered: Oct 2001
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posted 08-22-2004 01:49 PM
quote:
Originally posted by Rare67:
How about the Comp 270S, Nostalgia Plus, or the XE274H [This message has been edited by Rare67 (edited 08-21-2004).]
I am using the XE262H. From what I understand, it has the valves timed to open with less overlap so that the cylinders fill more completely, and valves timed to close with less overlap so the piston compresses more during the up stroke to power lower compression engines as if they were high-compression. This may not be an advantage to an already hi-compr motor. The race guys here love the 270S, but I would go hydrualic for a street car as a matter of personal taste and laziness  Charlie
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Rare67
Journeyman Posts: 16
From: Jefferson. MD
Registered: Mar 2004
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posted 08-23-2004 08:15 AM
quote:
Originally posted by MidLifCrisis:
Do you ever get up to Jimmy Cone in Mt Airy on the 1st & 3rd Saturday nights?
Haven't been there yet, but its on the "to do" list. Paul
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Rare67
Journeyman Posts: 16
From: Jefferson. MD
Registered: Mar 2004
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posted 08-25-2004 10:11 AM
Would the 270s be ok with 11:1 on pump gas?Another option is the 282s, but would I see an improvement over the current cam? They seem similar. Paul
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V8 Thumper
Gearhead Posts: 4377
From: Arizona
Registered: Dec 2001
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posted 08-25-2004 10:48 AM
270S is great for low-end torque, and you could play with the lash for more/less overlap. 282S is real close to what you're running now; choppier idle than the 270, and softer below 3000 rpm. I've run both in a 10.06:1 motor on pump gas, no problems at all. Aluminum heads are more forgiving for detonation however.On the lash issue... where do you have them set now? What is Crane's recommendation? You might try opening them up (+.006), see how much low-end you gain. It's easy and dosen't cost you a dime 
SOLIDS RULE   ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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