Thread: carb ?

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Carb CFM is an interesting subject to be sure.. Just had a 327 on a dyno and here is what I learned/saw.. First the engine spec. 327 (u knew this) performer intake and Vortex fast burn heads............ With a 750 mounted @ 6000 rpm is was consuming 489 cfm .. HP was 371 . Then a 600 was mounted and again @ 6000 rpm it consumed 467 cfm.. HP 351., Looking at the numbers two things stand out, the engine never consumed all that was available (cfm) and that the larger carb did run better with a 20 point difference in air and HP. So it seems to me that the 600 cfm was not the best carb size. I understand intake charge speed but this sure adds a question mark to the general school of thought, as I see it.

Originally Posted by DennyW

I'm really glad you saw the difference. I was put down pretty good for my calculations on picking a carb. I take the ci x 2. In your case, 327 x 2 = 654. If it's over half, like the 54, I go to the next whole number. So, I would use a 700 + on that motor, with vacuum secondaries, and your in. If you get a chance, maybe not now, but it would be nice to see what the 700 did in comparison.

(Oh wes ? this is an example my friend).

Wish I had that luxury, I sure did find that little test note worthy. The math you have there spits out some good tuning numbers, can not get any easier then that. I will use it........

Originally Posted by DennyW

I'm really glad you saw the difference. I was put down pretty good for my calculations on picking a carb. I take the ci x 2. In your case, 327 x 2 = 654. If it's over half, like the 54, I go to the next whole number. So, I would use a 700 + on that motor, with vacuum secondaries, and your in. If you get a chance, maybe not now, but it would be nice to see what the 700 did in comparison.

(Oh wes ? this is an example my friend).

Denny w I like your carb math . It's COOL and will work for me TANGO

Wrenchinrick,all the info mentioned befor is correct but don't scrap that holley just yet.If you use that carb again start ingine and look into carb,see if fuel is pooring in if soo floats set to high,have also seen things like,needle stick in seat letting in to much fuel,or found things like dirt and thred tape in needle seat.