I think so, but give me a double check. My 427 will actually be a 433 (427 = .030 overbore) The math I used:

433 x 7000rpm \ 3456 = 877

877 x .85VE = 745cfm needed.

I have a chance to score a brand new 780cfm carb for a very reasonable price. It is a vacuum secondary carb too which is what I prefer for my application.

im using a 3310-1 on my 427, im happy with its performance.

Do you have a manual or auto trans?

i have a manual trans in the 66

Rich:

We run 780s on all of our 427s and they seem to do ok...

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I used to run a 3310 on my 427/M20/4.10 combo..I used to zing it to 6500+ all the time smile.gif
Just a mild oval port,original 390 HP/427 with an LS6 cam and small tube headers

Ditto the old tried and true 3310-, 750/780cfm carb!!!

pdq67

The factory GM/Holley 780 carbs are really nice, they have adjustable air bleed screws on top of the carb, sure helps tune in the idle with a hairy cam.

Looks like a nice carb for a street 427. graemlins/thumbsup.gif

Do yourself a favor, hook up a vacuum guage and watch it, or have a friend watch it while yuou go through the gears. Watch that guage just before every shift. My 433 was pulling vacuum as the tach crossed 6000 and nearly 5-6" when I shifted ( maybe at 7000 ? - tach sucks).

And yeah, I know what the equations say. But test it.

For bracket consistency you should be fine, but for all out ET I'd put my money on an 830 cfm HP950 or the 830 cfm "Nascar" carbs I see on Ebay for $300 or so.

750/780 CFM is plenty to run low 9's/ high 8's in dedicated race cars ...ie: Super Stockers.... Granted you car isnt designed to do that but for all round use those carbs are very drivable , tuneable , reliable with enough air to satisfy most needs.A very good all round selection.

Hate to step on a fellow 'Rodders post, but are you saying I shouldn't have any vacum at WOT close to shift? I figured i'd want a little right?

no, if the carb is restricting the engine at wide open throttle at the top of it's intended operating range there will be vacume below the throttle blades, so if sized properly there would be no vacume when she's all wrung out smile.gif

Didn't 302 Z-28 camaros run 780 also? a customer of mine has an original Z and it has a 780. The carb sure works nice on his tiny engine.

Badbob...

Yes the 302's came with 780's.A very forgiving carb those 780's.... As an example years ago a friend of mine had a 69 Z28... a real one...and his carb started acting ignorant and needed rebuilding... This was his daily driver so I loaned him one of my carbs that was sitting around....A Holley 0-2818 OE 327 carb 585 CFM 4150 vacume secondary..... He ran his car at Fremont several times while stock and generally would run in the 14.40 to 14.60 range with the 780...... He took it to Fremont with the 0-2818 on it and ran several 14.40 to 14.60 ish range passes.For all intents and purposes it ran the same with the smaller carb..... His was a typical M21 / 3.73 combo..... sort of indicating that at least in his case he didnt need the extra air capicity... I would think that since it ran the same that with the 780 it wasnt capable of pulling a full 780 cfm out of it.

The interesting thing about that last post is that the Z/28 mentioned didn't run WORSE with that bigger carb. That 780 carb must be pretty forgiving (ie: vacuum secondaries probably help).

Bottom line: I'm going to purchase a '66 vintage (new in the box!) 4150. If it turns out later I'll need more carb, I still shouldn't have trouble selling this vintage carb.

Rich,

You cant tell from the dragstrip use but the 0-2818 did run alittle bit better in around town street driving... Not a huge difference but enough to notice.Those 302's were sorely lacking in low speed torque and the smaller carb seemed abit better and certinally didnt hurt the ET any.... But with those 30-30 Duntov cams (254 deg @ .050) that GM put in the 302's they didnt really get going hard till 4000 RPM and up.... So the low speed driveability of those 302's wasnt going to be the greatest anyways.

Drop an old -097 Little Duntov solid in a 302 and pick up some of that missed lowend!!!

She should still make good power b/c they used it in the 340hp and 360hp/327 motors!!

pdq67

Pdq.

I couldnt agree more.I do understand GM's reasoning for developing the 30-30 but for all that effort it gained them so very little with respect to actual performance.In my old reprint books nearly all the solid lifter 57-65 283/327 Vette's ran 14.0 - 14.60 .I cant recall a single mention of a 13 sec pass and just a couple in the 15's.... And haveing owned the 097 and driven and co piloted at least a dozen 30-30 equipped cars.... I'll still take the 097 over the 30-30 in nearly every case.

As far as his Z-28 goes his was stone stock except for tires , shocks and tune ups.... right down to the cast iron manifolds and smog pump.... Even I wouldnt have put an 097 in an origional Z !
;)