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Discussion Starter #1
I've had this problem for a while now and it's really starting to get to me. My engine doesn't seem to have the high rpm power I feel like it should. Here's my setup:
351W, 1970 W heads w/ 3 angle valve job, Edelbrock performer RPM intake, 750 holley vac. sec carb, Edelbrock Performer rpm cam (224/234 dur @.050/ .496.520 lift), crane high rate valve springs, Ford duraspark dist., Accel 45k volt coil, Accel 8mm spiral core wires, Factory replacement control box for dist, full length summit headers, 2" dual ehaust
Ok, anyway the engine has great midrange power (2500-4500 rpm) but simply dies out at the high end. There is nothing above 5000rpm. This bothers me because the 302 I pulled from it felt stronger in the 4500-5000 range than my windsor. the 302 was stock except for a 4bbl (performer rpm and 600 holley) and headers. The engine doesn't really cut out or anything it just tapers off in power sharply. I've tried jetting the carb,playing w/ timing, and re-curving the dist. but nothing seems to help. Is it possible the control box for the ignition is taking out timing in the high end. I know this is a stretch but that's kinda what it feels like. Anyone have some insight/ thoughts/ideas as to how I can improve my high end.
thanks,
Jeremy

-You can never have too much power, just not enough traction.-
 
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Discussion Starter #2
The control box could very well be part of the problem. Some of them reportedly have rev limiting features. With all that other nice equipment your running, why not get a Hy-Fyre box or something? What does the timing go to at higher RPM?

Also...the 2" exhaust is suspect...you've got high rpm setup (RPM manifold, long tube headers, etc) but you exhaust is going from 3" at the headers to 2" at the back. Its possible that might choke it down enough to show up.

Lastly, you might want to get a vacuum guage mounted int he car...when you get to the point that you feel the power is dropping off, be watchign the vacuum guage. The power valve in the carb might be closing due to vvacuum coming up enough. Might need to change the power valve to a lower one.

1970 Fastback, 4V 351C, various colors with black interior
 
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Discussion Starter #3
How are your valves adjusted?
Hydraulic cam I assume?
Is it possible that your valve train is rev-limiting you?
 
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Money pretty much prohibits me from buying a new box right now, otherwise i would definatly get a much better one. I know the exhaust isn't up to snuff and that is definately on the to-do list.
I really don't think the valve train is the problem, there doesn't seem to be any valve float or nothing, just no power.

-You can never have too much power, just not enough traction.-
 
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Discussion Starter #5
I would also suggest the exhaust as a culprit. It may flow well enough low end, but just can't push enough up top. Especially with longtubes, with the backpressure aft the headers, they can't create the vacuum as they are designed, and won't 'pull' the exhaust out like they should.
Of course, you need enough spark to even get to that point, so that is where I would start.

'66 droptop, 289 C4 auto.
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A 351W isn't going to have the top end like a 302. With a moderate cam like yours I really don't see much power past 5000 anyways. Remember, those extra cubes and stroke bring the power band down.

[color:red]1966</font color=red> [color:blue]V8</font color=blue> [color:red]Coupe</font color=red>
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5 speed, 4.11s, 10.13 in the quarter mile.
Oh wait, that was a Sammy Haggar song...
 
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