What carb do you reco.?

Newbie Here. I just bought a Scout II with a Ford 460 and need some carb. advice. The 460 is spec. out as follows: BIG BLOCK 460 BORED OVER 30 (ABOUT 500 HP-600 FTLBS TORQUE) WHOLE MOTOR IS BALANCED CLAY SMITH CAM ( 2240 DURATION, .525 LIFT) ROLER ROCKERS AND LIFTERS DOVE HP HEADS HOLLY 650 DOUBLE PUMPER ALUMINUM WIELAND STEALTH INTAKE MSD TIMING CONTROL MSD IGNITION ALUMINUM RADIATOR 4 CORE My buds tell me the 650cfm is too small to realize the full potential of the 460. What do you guys think?

Reply to
jimpascale
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Two major considerations are max useable engine RPM which your cam grinder should be able to help with and the displacement of the engine which you can calculate easily. As far as your HP & torque numbers, thay are a bit optimistic with a 650 carb - I don't know that that size carb can produce those numbers. If you use "calculate carburetor size" in Google, you will find numerous calculators. If your engine can produce 100% volumetric efficiency which few naturally aspirated engines can achieve, it will need something over 800 cfm at 6000 rpm. I don't know for sure but, I think your cam duration is 240 (typo?) with a .525" lift which should give you good mid range if properly installed and timed. This is a relatively mild grind for good torque. I would suspect that your engine would not produce peak HP much above 5000 rpm if that much with that duration and lift. If that is the case, the

650 will be about right. The worst thing you can do for your engine is over carb it. It will only gag coming off the bottom end. Forget what your "buds" are telling you and go with the what the numbers tell you. Unless your Scout is strengthened considerably with much improved brakes and chassis, I would not want to unleash the full potential of your 460 very often - it will break things.

Lugnut

Reply to
lugnut

Lugnut, Thanks for the good advice. My Scout hasn't arrvied yet. I bought it on eBay. The specs. I quoted came from the eBay ad, which I shared with some friends who mentioned the carb is too small. I'll do the goggle search as you suggested. Thanks again. JIm

Reply to
jimpascale

Here is the standard formula for figuring out carburetor size.

CFM = (cubic inches x rpm) divided by 3456

VE = (cfm x 1728) divided by (cubic in. x rpm)

Another CFM but takes into consideration Volumetric efficiency

CFM = (cubic inch x rpm x volumetric efficiency) divided by 3456

This should give your friends something to do for a couple of minutes.

...Ron

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68'RS Camaro 88'Formula 00'GT Mustang
Reply to
RSCamaro

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