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Discussion Starter · #141 ·
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Discussion Starter · #142 ·
And that’s a wrap for today. 11.72, 11.75. 11.79, 11.84, 12.08 (spun)

She’s running out of fuel up top, no doubt about it.

I’ll make a pass or two in the AM (cool air) and head out.
 
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Discussion Starter · #145 ·
Not easy to change bleeds in the carb then without removing the restriction and tapping.
You have 3/8" lines, what fuel pump again?
Carter Strip pump. I need toat least remove the sock, but probably upgrade to 1/2” to the mechanical pump. Then, I have a block 90° that’s late to leave this car. These items will be updated before Midwest Drags. Hopefully we see some 11.50s that week.

PS I wish I would’ve tried the locked out MSD on my 496 to see the difference. The car leaves on a mission.
 
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Carter Strip pump. I need toat least remove the sock, but probably upgrade to 1/2” to the mechanical pump. Then, I have a block 90° that’s late to leave this car. These items will be updated before Midwest Drags. Hopefully we see some 11.50s that week.

PS I wish I would’ve tried the locked out MSD on my 496 to see the difference. The car leaves on a mission.
You didn't want to go to a non stock looking pump, like a Holley 12-454-20 170 gph? It says to use with a regulator, but it works fine without one.

With a mild converter, locked timing usually gives stronger 60'. I found .1 in the 60' when I locked timing versus 26 initial, 36 total all in by 1700 rpm, with a tight 10" converter that flashed to 2300 rpm, and 3.42 gear.
 

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Not trying to debate the larger fuel pump and lines definitely a good idea but my sons 406 made 600hp on the dyno and went almost 125mph with a stock auto zone pump and stock 3/8" lines/pu.
Timing locked at 36* and 3.42's
That said he was probably 1k under what he made peak hp going through the stripe with the lower numerically gears.
Does the extra 104 ci make a difference or is 600hp 600hp?
 

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Carter Strip pump. I need toat least remove the sock, but probably upgrade to 1/2” to the mechanical pump. Then, I have a block 90° that’s late to leave this car. These items will be updated before Midwest Drags. Hopefully we see some 11.50s that week.

PS I wish I would’ve tried the locked out MSD on my 496 to see the difference. The car leaves on a mission.
I hope to see 11.60s tomorrow
 

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Discussion Starter · #152 ·

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Discussion Starter · #153 ·
A sample of the air today.
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Discussion Starter · #154 ·
Not trying to debate the larger fuel pump and lines definitely a good idea but my sons 406 made 600hp on the dyno and went almost 125mph with a stock auto zone pump and stock 3/8" lines/pu.
Timing locked at 36* and 3.42's
That said he was probably 1k under what he made peak hp going through the stripe with the lower numerically gears.
Does the extra 104 ci make a difference or is 600hp 600hp?
At what rpm is it making 600 hp? This engine is at 600 hp by 5000, pump is actuated far less times, relatively speaking.

But, this certainly feeling like a fuel issue to me. I might just try to shift to drive tomorrow…bang some more torque at the end to see what happens. My guess is the loss of gearing makes it a wash. A 28” tires makes this go away 😂
 
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I would recommend a fuel pressure Monitor inside the car or at least an afr gauge.

Fuel pump rating are free flow and rule of thumb are half of that at working pressure of 6-7 psi.
Another rule of thumb is you need actual 10 gph per 100 hp.
So - for example - when you need to fuel 650 horses i would aim for a pump that can provide 130 gph at peak hp.
So a 130gph pump is the bare Minimum i would say.
Best is one with proper pressure like 15-16 psi, or edelbrocks 10 psi 1712 pump. i use that one with my man 496 with a billet Regulator.
Only use straight fittings.
Works for me with 3/8 lines and pick up.
Can run 0-130 mph and pressure is Rock steady
 

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At what rpm is it making 600 hp? This engine is at 600 hp by 5000, pump is actuated far less times, relatively speaking.

But, this certainly feeling like a fuel issue to me. I might just try to shift to drive tomorrow…bang some more torque at the end to see what happens. My guess is the loss of gearing makes it a wash. A 28” tires makes this go away 😂
I'm in no way doubting what your feeling.
He was making it at 6500.
I also believe lack of gearing and converter not spec'd for 3.42 is also "band-aiding" it.
If he had 4.10's , I "feel" the pump at a minimum would be an issue.
 

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I would recommend a fuel pressure Monitor inside the car or at least an afr gauge.

Fuel pump rating are free flow and rule of thumb are half of that at working pressure of 6-7 psi.
Another rule of thumb is you need actual 10 gph per 100 hp.
So - for example - when you need to fuel 650 horses i would aim for a pump that can provide 130 gph at peak hp.
So a 130gph pump is the bare Minimum i would say.
Best is one with proper pressure like 15-16 psi, or edelbrocks 10 psi 1712 pump. i use that one with my man 496 with a billet Regulator.
Only use straight fittings.
Works for me with 3/8 lines and pick up.
Can run 0-130 mph and pressure is Rock steady
So which is it, 10 gph or 20 gph per 100hp?

Rule of thumb 10 gph per 100 hp. = 10 gph per 100 hp

To fuel 650 hp aim for 130 gph pump. = 20 gph per 100 hp

Contradicting your self here.
 

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With that tall gear, I hope you're able to do the entire 1/4 mile in 1st and 2nd gears. When I ran my 3.08 gear a few years ago I did some experimentation and found that if I shifted into 3rd (TH350 trans), it would absolutely dog the acceleration and hurt my MPH by about 5.
 

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What size needle and seat do you have in the carburetor? Running a similar setup I found that once I crossed the 600 hp mark I had plenty of fuel pressure but the fuel bowls were running dry at the top end. I upgraded to 0.120" needle and seat and it fixed the problem. If nothing else, it is a very cheap upgrade if you have 0.110" needle and seats in it. This was also way before they added ethanol to the gas as well.
 
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