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Discussion Starter #1
I have a 69 351w bored 30 over with flat top pistons, electronic ignition, rpm air gap manifold, 1.6 roller rockers, performer rpm heads with 1.90/1.60 valves, long tube hooker headers, and presently a 600 holley 4160. The car runs pretty good now, but i recently had a 750 3310 given to me. I have always heard too big of a carb is worse than to small of a carb. So should i stick with the 600 or do i have enough motor to justify swapping it out for the 750? I really appreciate any input.
 

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Just my .02 cents here...get a gasket and try it...if it proves to be too much carb, put your old one back on it. In the past (like in the '70's) I had a standard 351w with a 2bbl and I put a different intake and a Holley 650 on it, it ran but I had to change the jets and run hotter plugs....after about a summer of it...I put the 2bbl back on.
 

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Try the 3310, but unless the 3310 is an 'old school' type with the secondary metering block and not the cheapie secondary metering plate, you'll probably like what you've got better for throttle response. Remember that GT 390s came with 600 vac sec Holleys, and even 428CJs came with 735s! FWIW, I ran a 660 vac sec Holley Street Avenger and an old-school OEM GM 3310 780 on back-to-back runs of my 393W and got the same ET/mph... I wholeheartedly recommend the Street Avenger series carbs! They're more tunable than the cheaper line. Proper carb tuning is fast becoming a 'Lost Art'.
 

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Discussion Starter #5
The car is a manual. I sort of thought i would be better off with the 600. I may bolt the larger one up and give it a try, but i have heard they can be a pain to get dialed in right. I will admit carburetors are not my strong suit, but im pretty confident i can get it running right. Good news is i got it for free, and if i cant get it workin i can just put the old one right back on. Ill give it a shot and see what happens when i get the chance.
 

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Based on rpm and cam I'd say too big, but what the heck, give it a whirl if you feel like it. I just put a 3310 on a friends 302 ( a little warmed over, 360hp, 6500rpm, 4 speed ). It took quite a bit of tuning but it's running pretty good. No four corner idle is what stinks with a car that's running a big cam...have fun!
 

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IF you have a vacuum guage, it should be pretty easy, just dial it in for the most vacuum at idle, and then see how it does..
 

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Yeah, I gotta admit the 3310 does lack a 4 corner adjustment that would be rally nice, but I have actually been playing with a 600 I picked up from a swap meet - went through it as much as I a could (Metering blocks were absolutey welded to the body!! I was afraid I would crush or break something, so I left them and rebuilt everything else)....long story short I'd have to say that the 600 runs better on my 425 HP than the 750 does. I had that same 750 on a much bigger motor at one time - so I jetted it down and went with a different spring rate and lower volume squirter pump to compensate (may need more tweaking yet..?) runs OK, just a bit to rich still
 

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Smaller carb, more responsive bottom end/around town, bigger carb=better top end. Or at least that is the basic internet wisdom. I tend to agree with it from my experience. on my 69 351W, that has lumpy cam, auto trans and 3.89 gear, my 670 Holley is just right..Although, I have a 715 with the lemans bowls waiting to go on,after I build the motor...
 
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