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dual solex or webers?
Posted 22 March 2010 - 05:21 PM
Posted 25 March 2010 - 07:18 AM
Posted 25 March 2010 - 10:19 AM
Posted 25 March 2010 - 10:53 AM
Remember, going too big is just as bad as going too small.
Posted 26 March 2010 - 03:12 PM
Posted 26 March 2010 - 03:36 PM
350 CID x 6600 RPM X 0.80 volumetric efficiency / 3456 = 534 cfm needed.
That is the math for a basic small block chevy in semi-stock form, and what it needs carb wise to be efficient.
Do the math on your combination, and decide for yourself.
And just for the record; most people tend to over carb the bejeebus out of their motors.
And another thing; A K&N air filter, and a set of expensive spark plugs does not make your engine a "race" engine. The volumetric efficiency doesn't increase to 100% by putting some flowmaster stickers on the window. And pretending the motor will spin another 3000 rpm more than it realisticly will, or will normally see isn't going to benefit you either. Use the formula honestly for best results.
Posted 26 March 2010 - 04:14 PM
But there is a lot more going on than just "CFM" when it comes to carbs...
manifold layout and design, multi-cylinder vs. IR set-ups, different cfm ratings for style carbs...etc. everything come into play, sometimes in ways we wouldn't expect... one quick example; GM offered basicly one size carb, the Q-jet on everything from a 250 cid 6 cly to their 454 cid big block. that really doesn't fit the above math very well, and before anyone jumps on "they made a bunch of different size Q-jets" they really didn't, go check.
If you're really interested, Smith and Morrison's book, "Scientific Design of Exhaust and Intake Systems" is a great primer to get you started.
Posted 26 March 2010 - 06:30 PM
Posted 26 March 2010 - 11:33 PM
but i can tell you, that a 32/36 is plenty of carb if you run bigger jets.you could actually choke out the engine way rich, before you got to the end of the size range.
i know, because i tried it.jerry swears up and down that his big carb motor has more power.it is possible,but i think it would be a very fine line ....
dual 34's would be a little overkill, but the thing to keep in mind is mounting.when you have synchronize it ieasier to have them in line than to have some crazy setup.....the less complicated the better.
downdrafts will definitely work out better in the long run.i have a set of sidedrafts currently, and they are looking at being fairly difficult to setup properly, althought they would look ************in killer.
see if friends of friends and such have something you can kinda mock up...
Posted 27 March 2010 - 09:21 AM
I say go for it!
Posted 30 March 2010 - 10:55 PM
Posted 31 March 2010 - 08:30 AM
Maybe you menyioned it already, but what is your current plan for the manifold or manifolds? I had thought if I were to do this all over again. I would probably buy a couple of aluminum blocks from an online metal supplier. I found a place that would sell a 3" x 3" cube for $30 or so. I would have the intake part drilled at a machine shop. Then I would drill and tap everything else into them.
150 sounds about right. I used 3eyedwagon's calculations. My carbs came out to 165 at 5000 rpm.
Can't wait to see what you come up with!
Posted 31 March 2010 - 09:43 AM
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