I am in search of a carb that will work well with my 396. The motor will be approx. 404ci after overbore, and based on the Holley Website, looks like I need 650-750+ cfm.

I am planning on using an original 69 CI intake, which appears to have been for a Qjet carb.

From what I understand Holley no longer makes a 680 or 780 spreadbore? I guess I could use a 750 DP with an adapter plate, but that doesnt seem like the right thing to do to me.

Has anyone else tackled this problem? Any good carb recommendations??

Thanks,

John

Use the Q-jet. You won't find a better street carb.

I second the use of a Q-Jet... Holley & Edelbrock both manufacture them now if you want a new (more tuneable) one and you'll love it once it's setup and going. I have an 396 (402) and unfortunately I have a Performer RPM Square Bore and really wish that I had the Spread Bore Version. As it is, I would have to use an adapter for Q-J and that would raise the carb too high and knock my hood. The Q-J gives you better mileage when being polite and a lot more "ummmph" when being heavy footed.

Warning... Quadra-Jets vs Holley's or Carter's (Edelbrock style) has allways been a love'm or hate'm affair. I like them all but it all depends on your driving habits, what you plan on doing and how much you are willing to "futz" around with it. They all have their Pro's & Con's so there are many options to consider.

Hope it helps.

Any thoughts on the vacuum secondaries vs. mechanical? My car is going to be a 4 speed, and it will be a weekend car with occasional strip usage.

I will take a look at the Holley Q jet..is there any particular # for the carb I should be looking for?

holley still make a spreadbore carb list number 6210 650 double pumper mech secondaries.this a Qjet replacement 65-70 396-402.and as far as i know holley still makes other spreadbore carbs.i know jegs has the 6210.

chris

Thanks Chris.

Is 650CFM going to be enough for this motor? I was thinking that I needed 750.

Anyone know if Holley used to make different (larger) spreadbore carbs, and what the #'s might be?

For maximum performance,a Performer RPM and a 3310 would be best.

mr. 4 speed..

Will the performer RPM fit under a 69SS hood? I am worried about clearance issues.

Also, I am looking in a Summit book..I see Holley has carbs listed that are model 4160, but the # given for a 750cfm VS is HLY-0-3310 C or S..Is this the one you are referring to? Will this carb go right onto my original manifold, or will I need a square hole setup like the performer?

The RPM will fit under a 69 SS hood.No clearance issues either using a 14x3 open element/stock style air cleaner
Yes,that is the carb I'm referring to.
It will not fit a stock spreadbore intake

John,

Here it is, first hand data from yesterday. My 408CI 9.5/1 oval port motor w/ 226/236 @ .050 hyd cam and a set of headers went 99.09 MPH with a Performer 2-0 and a Holley 770 Street Avenger ran as set up right out of the box. The Performer 2-0 pulls well down low, but seems to flatten out at 5000RPM in high gear. Depending on what you are running, for a bone stock 396/325 HP motor you could use the Performer, but if you have any mods at all [cam = 220 at .050 or bigger], I would go with the RPM. Maybe even the Weiand Stealth. Any of these will fit under the stock '69 SS hood.