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#1
10-17-2019, 08:19 PM
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Had a chance to put my car on a dyno today
Guess what Horse power this put out?
Build 400 .060 Flat top with one valve relief Crower 60240 cam #15 small valve heads 87cc Performer Intake HEI 14 initial 35 all in at 3000 Quick fuel 735 AFR 12.8 |
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#2
10-17-2019, 08:25 PM
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Mustang or Dyno Jet?
4 speed or auto? |
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#3
10-17-2019, 08:27 PM
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275.....
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Carburetor building & modification services Servicing the Pontiac community over 20 years |
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#4
10-17-2019, 08:29 PM
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Quote:
Auto |
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#5
10-17-2019, 08:31 PM
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286
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#6
10-17-2019, 08:47 PM
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217 peak horse power
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#7
10-17-2019, 08:50 PM
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I didn't think you could build a pontiac with that low of horse power. I was hoping for 300.
Something definitely went wrong. Greg |
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#8
10-17-2019, 09:46 PM
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Is it fun to drive now? Just wait until you get it dialed in
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"At no time did we exceed 175 mph.” Dan Gurney's truthful response to his and Brock Yate's winning of the first ever Cannonball Baker Sea-to-Shining Sea... Still have my 1st Firebird 7th Firebird 57 Starchief |
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#9
10-17-2019, 09:56 PM
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Lucky if above 250 to the wheels.
__________________
" Is wearing a helmet illegal" Mike Kerr 1-29-09 |
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#10
10-17-2019, 10:22 PM
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I had that combo (255-260 HP at wheels)
Crower 60240 is a smooth running cam but hard to dial in. I had to advance that cam 2 times to get any performance out of mine on a 389 (first 4 degrees and then 6 degrees advanced was just right).
It's strange because the cam supposedly comes with 4 degrees dialed in but if you go dot to dot it will be a dog. Must degree it on a wheel to verify. You'll get 255-260 HP at the wheels with that cam, all done making power at 4800-5000 (but revs higher no problem). It makes about 325 HP at the flywheel x 20% loss or about 260....your compression ratio looks to be about 8.5:1 which is fine with that cam (and will run w/ no detonation worries on 87 or 89 all day long). I had 90cc small valve #11 heads and made decent power. Its a driver cam.
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1974 Lemans Sportecoupe GT (daily driver) .030 over 354, #47 heads (84cc), Lunati voodoo 700 camshaft (207/213 @ .050), logs, 2.5 duals, X-pipe and Dynomax super turbo mufflers, 3.08 rear |
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#11
10-17-2019, 10:42 PM
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Quote:
When I was getting parts for this build I originally bought a summit 2801. Does it have to be degreed? would it work with my set up? |
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#12
10-17-2019, 10:55 PM
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Quote:
Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
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#13
10-17-2019, 10:59 PM
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Quote:
Thanks |
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#14
10-17-2019, 11:04 PM
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Quote:
And the compression is about 8.8:1 |
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#15
10-18-2019, 06:06 AM
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You need to mill those heads to get the comp up to 9.5 to 9.7 and that will bring the cranking compression to the needed 180 range that the 3.750" stroke of 350, 389 and 400 motors need so to speak.
This means you need a 10 cc reduction in chamber volume, so milling the heads .060" on the deck and the Intake flange will do the trick. Note that milling this much off the heads means that you will have use only a bead of gasket maker on the valley pan and you might also need to trim some meat off of the bottom of the Intake Manifold to get things bolted up and sealed , but the power gain will be worth your time , money and effort! Be sure that once the milling is done you lay a head gasket on the head and roll/ polish over any sharp edges of the deck that now stick out passed the fire ring of the head gasket.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! Last edited by steve25; 10-18-2019 at 06:21 AM. |
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#16
10-18-2019, 07:07 AM
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Quote:
I wouldn't say anything went wrong given the specs you provided. A few years ago a bunch of Pontiacs hit the chassis dyno. Including myself with my stock 400 RAIII, auto. I made 301hp while most of the other 400 cars were in the 270-280 range, and some of them had aftermarket cams and what not. A few of the 455's barely hit 320-330hp. But I've had a lot of years racing and tuning on the car. That day I was running 13.60's at 102 at the track at a 3900 lbs. race weight, which coincides well with the RWHP numbers I put up. Edit: Okay I see it now. 217 is lower than I would have expected for that combo. |
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#17
10-18-2019, 08:10 AM
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When people talk about a good tune which my car needs, how much horsepower can be gained by a good tune?
Thanks |
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#18
10-18-2019, 08:43 AM
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If your air to fuel ratio is good through out the motors rev range which it seems to be from your posting of a average 12.8 ratio then the only thing left in terms of getting your motors needs peaked out is to make some dyno pulls / run's while putting in timing changes and to try out different octane fuels.
One thing to watch out for if you go playing with different octane fuels is that the air to fuel ratio can need to be changed from what it is now . With your motors current compression ratio I can't see why anything more then 87 octane is needed to keep the motor alive , and don't forget that running a octane level higher then the motor needs only cuts into the power that a motor makes as the RPM goes up! For a street motor I am not sure if this is a can of worms you want to open because at most your looking at a gain of about 8 hp, and your looking for a missing 30 hp or more, so stick with just trying out some different total timing changes.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
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#19
10-18-2019, 09:47 AM
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Not a bad number for a conservative build.
I'm sure some in depth tuning will make it pretty snappy.
__________________
Carburetor building & modification services Servicing the Pontiac community over 20 years |
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#20
10-18-2019, 10:07 AM
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Quote:
Mild cam, mild compression, small valves,.... based upon other Pontiacs I've dyno tested, you may have another 15 or so HP. Nearly every stock headed Pontiac I've seen on a chassis dyno has put less than 300hp to the wheels. What is your torque, though? People focusing on HP with Pontiacs running unported heads, they are studying the wrong end of the dog.
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust |
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