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Holly 650 double pumper

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Old May 22, 2015 | 09:53 PM
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Default Holly 650 double pumper

Have 327-375hp. With Edelbrock
Performer 27011. Will the Holly 650 work ok????
Thanks for your help
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Old May 23, 2015 | 12:26 PM
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It depends... The Edelbrock EPS intake manifold's power range is idle to 5500 RPM so you're giving up some top end power if you have the stock "30-30" cam.

My '64 Vette's 327/365 came with a Holley 2818 600 cfm, vacuum secondaries carburetor and a 3.70 rear end with a close ratio M20 4-speed. The engine ran strong with the vacuum secondaries up to 6200 rpm. You'll need at least a 3.55 rear end and a light right foot to drive a 650 double-pumper on the street to keep from bogging the engine as the mechanical secondaries open up at low rpm.

My choice would be a 600-750 Holley with vacuum secondaries. (I swapped out my 2818 for a 3310-1 780 cfm, vaccum secondaries carb, and that combination ran well on the street as well as competition events, e.g., drag racing, auto-xin g.) YMMV.
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Old May 24, 2015 | 03:47 PM
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Default Manifold/ holly carb

Thanks for your reply. I was going with that manifold so it would fit under the stock hood. Not sure what rear gears are in. I do have a Muncie 4 speed. Also I was thinking about putting in a comp cam XER-287HR-12
I do not have experience in theses areas. Also using Edelbrock heads
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Old May 24, 2015 | 03:49 PM
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Default Manifold/ holly carb

Thanks for your reply. I was going with that manifold so it would fit under the stock hood. Not sure what rear gears are in. I do have a Muncie 4 speed. Also I was thinking about putting in a comp cam XER-287HR-12
I do not have experience in theses areas. Also using Edelbrock heads 185cc heads with 64cc chambers. Model 60895. Thanks any input would be helpful!
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Old May 25, 2015 | 05:07 PM
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The cam you mentioned is made for the Gen III LS block, not your Gen I SBC, plus it's an hydraulic roller cam with a best power range from 2800-7200 rpm. Definitely not a street cruiser cam.

If you use the Edelbrock aluminum heads with stock rockers, be aware that Edelbrock recommends using hardened pushrods 0.100" longer than stock for proper rocker arm/valve alignment.

Since you're induction system is restrained by your choice of intake manifold, I would try selecting a cam like the old 327-350 L79 cam. It's an flat tappet, hydraulic lifter cam with moderate lift, muscle car idle, and peaks out around 5800 rpm. (Click here for the Comp Cams L79 Factory Muscle cams specs.)

Of course all this depends upon the rear end gearing you have in your Vette. If you're replacing/rebuilding an original 327-375 engine, you should be okay.

Hope this helps!

Last edited by mr.beachcomber; May 25, 2015 at 05:08 PM. Reason: Corrected one typo error.
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