carb help

[73pony]

Need a little help understanding and determining the best route. Either Mechanical or Vacuum secondaries. Any help would be greatly appreciated. I am planning a 750 CFM carb. Fuel mileage is not a concern.

Here is what I have.

73 Grande

351C

Aussie CC 2V heads (slightly worked)

Headman Headers 1 3/4" primaries

Pertronix III ignition

T-5 5 Speed Manual

3.70 Trackloc rear

Custom grind cam

608/612 lift

225/232 duration

112 LSA

Full Roller cam

1.73:1 roller rockers

Stock bottom end

Compression calcs out to around 10.2:1

Holley Street Dominator Single Plane intake manifold.

 

[Jeff73Mach1]

You can use either, but given your specs a Mechanical secondary will give you crisper throttle response.

 

[73pony]

Thanks Jeff. That is the way I was leaning, just wanted some additional input.

 

[Jeff73Mach1]

Just keep in mind that with a mechanical secondary, you do have some responsibility in how it performs. Excessive gas at low RPM's will still bog the car down, but if you use some common sense that won't be a problem.

I think you'll be okay with a 750, a 700 might be okay too, depending upon the RPM range you intend to max the engine out at.

 

[c9zx]

As Jeff said either will work. I'd get a DP given your set up. You will need adjustability to tune the carb for your combination of parts The Quick Fuel carbs come with more adjustability than the Holleys and generally cost a little less. Another option is Bo Laws Performance (BLP). If you can provide them enough accurate information they'll custom build a carb for you and the calibration will be very close out of the box.