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Running 11-Second 1/4 mile with 2.56 gears, stock stall, and 225/70-15 Coopers


Dragginwagon467

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Had the opportunity to take my wife for a ride in the Monte this morning. The 225/70-15 Coopers did well on this trip…with judicious use of the loud pedal.
 

This run is with my old 750 cfm vacuum secondary carb, HEI distributor, and shifting at 5200 rpm (since the engine lays over at 5K rpm). Not positive if laying over is the normal flattening of the power or an issue that’s induced by insufficient fuel delivery in the car (smaller 750 vs. 850 cfm carb, or fuel line from the tank).
 

The car certainly leaves stronger with the VortecPro 510 than with my 496.  Considering the added weight (passenger, full trunk), worse air, shifting at 5200 rpm, and letting off 1-second before the 1000’ mark on a “back half of track” car, a 12.98 1/4 mile isn’t too shabby. 
 

 

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Get rid of the 750 vac secondary and put the 850  that it was dynoed with back on. The 750 is too small. That will fix it laying over on the top end. What fuel pump and size line are you using?? 

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7 hours ago, MC1of80 said:

Get rid of the 750 vac secondary and put the 850  that it was dynoed with back on. The 750 is too small. That will fix it laying over on the top end. What fuel pump and size line are you using?? 

Process of elimination really, I put the 850 cfm carb back on and I’ll give it a shot to see if it lays over. Anyhow, I swapped carbs urgently for another reason.
 

Who would ever have thought an air cleaner carb stud  and wing nut could nearly cost you an engine? I noticed my air filter lid was nearly spun around backward, and when I went to fix it, I noticed the stud was broken. Thankfully, I noticed before the stud separated from the wing nut and dropped in the engine. 
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I went back to my earlier photos to ensure I didn’t have a jam nut on the carb stud (my mind was going a mile a minute at this point). Luckily, that answer was no. To be honest, I noticed the stud was bent, but didn’t think much of the bent carb stud since it was a “tomorrow problem” that solves itself when upgrading to the 850, which comes with a new stud  

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I removed the carb and tried for more than two hours but I could not remove the broken stud with an EZ-Out, lube, etc. I was hoping to fix it, and keep the 850 on the old engine for fuel line mock up. 
 

Anyhow, the 850 is on with the existing 1/2”braided fuel line setup. I was hoping to install with a more stock appearing inverted flare hardline setup. 
 

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Like this…3/8” inverted flare steel line from Carter Strip pump to Tee, 5/16” from Tee to bowls.

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The current setup OK from pump hose to the carb, but there’s a 90° at the fuel pump outlet which needs to go, but the inverted flare line removes this fitting.
 

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The car has 3/8” line, not sure if that’ll be a hang up on a soft-leaving car such as this, but I do have the 1/2” RobMC pickup and roll of 1/2” aluminum line if necessary. 
 

Anyhow, we’ll see how this pans out. 

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The 3/8 line could be an issue up top. Not as much down low. Big Red has the robmc 1/2 in tank pick up and 1/2 braided fuel line to the holley fuel pump and the same 1/2 line with a filter to the 950hp Holley on the 496. No fuel issues what so ever. 

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37 minutes ago, MC1of80 said:

The 3/8 line could be an issue up top. Not as much down low. Big Red has the robmc 1/2 in tank pick up and 1/2 braided fuel line to the holley fuel pump and the same 1/2 line with a filter to the 950hp Holley on the 496. No fuel issues what so ever. 

Why kind of power? More importantly at what RPM?
 

This engine makes more than 600 hp at 4800 RPM. The pump is not being actuated as many times per minute as it would be on an engine that makes 600 hp at 5800-6000 RPM. 

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Exactly, so if the volume of fuel is not there, power will fall off and possible you can hurt the engine. Lean condition. Remember, a big block has  bigger cylinders, valves and ports as compared to a small block at the same rpm. 

I'm actually going to try an 1000 cfm carb on Big Red.

And with 510 cubic inches, she wants fuel. Doesn't want to breath through a straw with a mask on. Plus it was dynoed with an 850. Obviously with a 750 you are choking those cubes.  

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2 hours ago, MC1of80 said:

Exactly, so if the volume of fuel is not there, power will fall off and possible you can hurt the engine. Lean condition. Remember, a big block has  bigger cylinders, valves and ports as compared to a small block at the same rpm. 

I'm actually going to try an 1000 cfm carb on Big Red.

And with 510 cubic inches, she wants fuel. Doesn't want to breath through a straw with a mask on. Plus it was dynoed with an 850. Obviously with a 750 you are choking those cubes.  

Makes complete sense. Went back to the dyno sheets, it’s using 745 cfm at 5200 rpm….explains  the power dropping off well. 
 

The 850 is bolted on now, unfortunately I didn’t get a chance to test it this weekend. 

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  • 2 weeks later...

I’ll come to this later and add some color…successful first outing with the new engine. drove 190 miles to the track. Racing with a tachometer for the first time with the Monte. 
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It comes out of the bottom very well. Traction off the line was definitely a little more complicated than with my 496. The engine is running out of fuel at 1200 feet, which is keeping the mph down. 
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Unloaded, ready to go. 
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Planning to race Mike Robert’s 571 CID monster in today.

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Yes, still sporting the obligatory stock tires (225/70-15 Cooper Cobras).DC92374E-2688-4EA7-8D53-9B8ED441975D.thumb.jpeg.32592df32943a09c35af2d999ce3e95a.jpeg

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  • 2 weeks later...
42 minutes ago, MC1of80 said:

Don't have any never will have Fakebook.  Nice numbers, which one are you?  Did the 850 fix your issues? 

Right lane. This race is from the same event, so it’s still flat up stairs. 
 

Unfortunately, I don’t have this video, the guy in the next lane uploaded it to Facebook. Cliff’s notes, he beats me all the way down the track, except for the last foot. I’m in camera on the launch, disappear, and then reappear after the 1/8-mile. 

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He had the better reaction time. A tenth quicker than you until the 1000' at which point the bigger cubes were showing their stuff. Nice!  Imagine how she'll goes with the 850cfm she was dynoed with. 

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9 minutes ago, MC1of80 said:

He had the better reaction time. A tenth quicker than you until the 1000' at which point the bigger cubes were showing their stuff. Nice!  Imagine how she'll goes with the 850cfm she was dynoed with. 

The 850 is on, it might be a fuel pick up issue in the tank or stock line issue. Either way, 275/60-15 tires at the next race, it won’t reach the problem rpm’s. 

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What rpms is that? A big cubic inch engine NEEDS volume. A factory 3/8 line wont feed the beast up top when she wants to breathe. 

A 225/70r15 is 27.4" tall and a 275/60 r15s is 28" tall. Maybe at most a 2-300 rpm difference, if that at top end. Definitely a bigger contact patch to get better traction out of the hole. Especially if using a drag radial. Regular street tire, slightly. 

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Although my little 402 makes like half the torque for your 510 I was able to shave .31 seconds off my 60ft time just going from a street tire to the Mickey Thompson ET radial pro in a 275/60/15. It’s not recommended for highway use but I did have a couple thousand miles on them with street use and didn’t have any issues other than not being able to drive through rain. But if it’s just a track tire I couldn’t recommend them enough! When I finish my 496 I’ll likely buy another set to try to out all that torque down. 

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7 hours ago, Dragginwagon467 said:

Right lane. This race is from the same event, so it’s still flat up stairs. 
 

Unfortunately, I don’t have this video, the guy in the next lane uploaded it to Facebook. Cliff’s notes, he beats me all the way down the track, except for the last foot. I’m in camera on the launch, disappear, and then reappear after the 1/8-mile. 

Cool Video, I don't have FB either but luckily its a "pubic' page so I was able to watch.  Thats a sweet Cyclone 

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3 hours ago, DragCat said:

Cool Video, I don't have FB either but luckily its a "pubic' page so I was able to watch.  Thats a sweet Cyclone 

Yeah, won't even open for me. 😞

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1 hour ago, MC1of80 said:

Yeah, won't even open for me. 😞

Thats weird, oh well guess Michael will have to be more productive with his Dragy video posts lol 

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12 hours ago, MC1of80 said:

What rpms is that? A big cubic inch engine NEEDS volume. A factory 3/8 line wont feed the beast up top when she wants to breathe. 

A 225/70r15 is 27.4" tall and a 275/60 r15s is 28" tall. Maybe at most a 2-300 rpm difference, if that at top end. Definitely a bigger contact patch to get better traction out of the hole. Especially if using a drag radial. Regular street tire, slightly. 

6300 rpm. I’m guessing the 60’ will drop to 1.83-1.84 if it hooks, we will see. 

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