RB 180 Headers tight fit

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SnowDrifter

SnowDrifter

Well-Known Member
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Apr 19, 2013
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Location
lotus
413
8.3 compression
5 Speed manual trans
3.00 independent rear end
3000 lb
Cam specs are an estimate
The Max pipe software calls for 47.5 inch primary tubes for 5000 rpm peak horsepower.
What is a good max shifting RPM for the 413 or 440.

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Old school ridiculousness I never saw a reason for. They look cool when done right, though.
 
RustyRatRod said:
Old school ridiculousness I never saw a reason for. They look cool when done right, though.
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Yes ridiculously quick this thing will be... wondering what's the top RPMs for the 413, 440 so I can finish my primary header tube length
 
SnowDrifter said:
I just threw that number out there wasn't sure waiting for my cam grinder to send me my specs.
Less duration shorter pipes. Higher RPMs shorter pipes
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I guess that would be more of the advertised duration been a busy week
 
Your lift numbers are from a Comp Cams Extreme Energy series.

That cam is 230 int/236 ext. Probably much closer to what you will actually get from the cam guy.

With a 413 if everything else is in line, peak should be in the 5400/5600 range. Depending on Gearing/Trans, It may be a little soft down low with the 8.3 to 1.
 
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I figure this is mainly for street car use, and a light one at that. Nothing wrong with a little less on the bottom end if it allows it to hook. I built several cars that way back in the 70's. Hook hard and pull big from 3k up. :)

Glad you have the rack. Not many would attempt that header configuration with conventional steering.
 
Since no one asked and out of curiosity, what cyl head & piston combo did you use to get 8.3 to 1 with the 413?
 
OldmanRick said:
I figure this is mainly for street car use, and a light one at that. Nothing wrong with a little less on the bottom end if it allows it to hook. I built several cars that way back in the 70's. Hook hard and pull big from 3k up. :)

Glad you have the rack. Not many would attempt that header configuration with conventional steering.
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I hope to be under 3000 with roll cage... Streetcar yes but built for racing
 
446-6, 9.5cr, hooker Competition headers(1-7/8”), bowl ported 346 heads, 230/230-110 hyd cam.
Made peak TQ @3900, peak HP @5200
 
Always went quicker in the 1/4 going to 6,000rpm with my 413 but I also have a 727.
 
thesiren74 said:
Always went quicker in the 1/4 going to 6,000rpm with my 413 but I also have a 727.
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Was that one of those older higher compression ratio motors.
With 8.3 compression a good cam and headers.
6,000 safe RPM for an occasional or a frequent shift RPM
 
I've got a similar cam in one of my 440s with the exception of lift.
The duration is what determines the rpm curve and torque and peak horse power. My combo is a 440 but the rpm of peek torque and horse power should be at very similar rpm. Torque peek at 4500 and horse power at 6200 rpm...
I believe that cam is too big for the low compression ratio, something with 225 duration @ 050 lift will work better.
 
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