Low on power?
I can blast off in second gear hold the brake lightly and only burn about 30’ then grabs and goes, I hear some can just jab it in 3rd and break them loose, I am lucky to jab it in 1st and break loose if it’s cooler out. FE 428 10:1 780 Holley vac sec open 3/4-7/8 with the lightest spring ,tall oval air cleaner, RPM performer, edelbrock heads, 36 total timing, hyd. Cam .539 280 ,at .050 230 lobe sep 110. 350 gears 29” x12” MT S/R tire, WR toploader. Runs great I just feel I am leaving some on the table, may try to get some Dyno and tune time. The tubes in side pipes are rather small, I guess that would be a good and cheap place to start? Any feed back would be much appreciated.
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Swap out the vacuum secondary carb for a double pumper and you’ll break em free.
The vacuum secondary carb is better for drive ability as the secondaries open as vacuum dictates. Mechanical secondary carbs just open up and dump power. Not as controllable. |
PS. Nothing has changed in the 5K miles and 22 years since l built it. Compression is 180-190
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The Everett-Morrison I used to have ran a 410 ci Windsor engine and it would break the tires loose in 3rd gear from about 3,000 RPM by just pressing the throttle smoothly to the floor. It was designed for maximum mid-range torque rather than peak horsepower. . . My current car, a Cheetah, has a 427 c.i., small block Chevy that will also roast the tires in the first three gears.
My opinion is that your engine is not optimally tuned for the type of driving you want to do. Rather than throw parts at it, I suggest you find a reputable dyno tuner who can both optimize your carburetor and timing, and suggest what other components might be limiting performance (e.g., carb, intake, exhaust, etc.). That will give you the best bang for your buck in the long term IF you can find the right dyno guy. |
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Replace with 650CFM Holley double pumper-04777C Try it fresh out of the box, do not adjust carb, do not adjust timing just yet. In addition, maybe check tire pressure in rear tires, want to burn out more, add additional pressure ;) Bill S. |
As others say replace your vacuum carb for a mechanical one. Quick Fuel 750 is highly adjustable. Biggest improvement I got was changing the pump cam to a red one. Gives great instant response.
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Those third gear tire spins can be a disaster. My cars rear end kicks out to the right in s snap..
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Bill S. |
A lot also depends on your tires.
With the Avon cr6zz, flooring it at the top of 2nd and 3rd gear is now a possibility (roush 427r). With the indy 500 tires the car came with, I'm pretty sure you could spin in 4th.. |
Spinning the tires is fun, and looks cool, but it's really a bad thing. It demonstrates lack of traction and control. If you mash the pedal and it hooks up and goes like stink, that's what it's supposed to do.
There's no such thing as too much power. Only not enough control. |
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In addition, most people want to eliminate wheelspin, so perhaps your cars previous owner set up his driveline and suspension properly to eliminate the wheelspin. Why take the wheel backwards from round to square other than to stroke your ego or show off to your friends? %/ Bill S. |
As we seem to be wandering off topic a bit, I'll add two things. First, when power and traction get high enough, something in the driveline has got to give. For a street car I prefer the weak point to be the tires. I'd much rather have to back off the throttle to keep the tires from breaking loose than to twist an axle. . . Second, I find it hard to believe that anyone who buys a Cobra doesn't have an ego with regard to engine power and performance, even if they never actually make use of all of it. For example, peak horsepower makes a difference in performance only at wide open throttle when approaching the car's maximum speed. Before that it is torque that defines performance. Yet many Cobra owners who will never approach maximum speed have paid an extra $20K for an engine with a big dyno peak HP number just so they can talk about it with friends and strangers. . . Is that a wise use of money? Probably not, but it is very much the way most of us on this forum think. Cobras are immensely impractical cars so it is completely sensible that those who own them want impractical amounts of engine power.
Mark Donohue said, "If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower." I doubt his quote would have been remembered if he had said, " .. you don't have enough traction." |
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If I wanted to do a burnout, in a parking lot with no obstacles I'd raise my rear air pressure from 18psi to maybe 28?
I pay for my own tires. |
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Sorry for getting off topic. I run a Bigs 950 CFM Stage 2 on my 514. |
Good point Patrick and that was the case which I corrected about 6 months ago, it was opening 80-85% but not much improvement. I even wired the vac sec closed and not a great deal different, the most I can get them to open is about 85% with the lightest spring. It feels more like a potent small block.
Incoming I don’t really want to do burnouts, I am just using that as a gauge if you will, I run 25 psi. |
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I did check again yesterday, looking at the butterfly’s they are opening fully. Would my old air filter element which is shorter create more vac to open secondary’s more? I want to try that but it’s off the road for a few more days. Thank you for your help
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