What carb?

[Eric_S68]

A little guidance on a new carb please.
My motor is/will be a 360 with J heads, LD340 intake, headers to 3" pipes and Flowmasters, Big Lunati cam. Msd ignition 6 something. 727 rev pat, 4.10 8-3/4" I dont know too much about this motor or setup I havent torn into it yet. I was told that the donor car with the engine, trans, rear combo with out a 10 pt cage ran a 12.20@1/4m

Do I want a Holley, a Demon, a Predator, an Edelbrock? A 935CFM holley is on it now, but that was just slapped on to get the car running and moveable. It Does well on beer/fun runs . :drinkers: :thumblef: I'm thinking in the 750 - 850 cfm range. But then what? , a double pumper or vac/mech sec's?

 

[BJR Racing]

Is this going to be street driven or raced?


BJR Racing

 

[AdamR]

Cant go wrong with a 750 double pumper. Maybe a Proform 750 for something a little more fancy.

 

[moper]

We need your intended use, plus things like header tube size, torque convertor stall, tire size, and if at all possible, some idea what "a big cam" is. In truth, I dont think you'll need anything over 750, and I'd lean towards a vaccum secondary, depending on the answers to my questions. Budget wise, you couldnt miss wiht a well tuned 3310 750 Holley, maybe a 770 Street Avenger, or 750 Street Demon if fundage allows. All will need some form of tuning, but they'll all do the job.

 

[Captainkirk]

Vacuum secondaries are always more forgiving. Double pumpers w/ mechanical secondaries will out-perform, provided you put the time into tuning it properly. You can't just slap one on and expect it to perform it's best on your setup. According to Holley's cfm chart, the best you expect your setup to flow is around 800 cfm at 8000 rpm, so I think a 750 would be a good start.

 

[Eric_S68]

It's gonna be Raced, but will be street driven to the local car meets. I did leave out that it has a 4200 rpm conv. Sorry to say I dont know the cam specs. Don't suppose there's an easy way to figure that out? As for tire size, I'm not sure yet either, what size i'll need for the 4.10's without running of motor at the end of the 1/4.

 

[moper]

Well, witht he 4200 stall, you can go with anything, really. I dont agree that DP carbs make more power. The right carb, will make the most power. At 4K+, both carbs will be wide open, and the vaccum carb will be better on the street in terms of response and milage(ok, milage aint a big deal..but....lol). The DP can be tuned to be as sharp as vaccum, but most guys dont pay enough attention to tuning to get it that good. Two weeks ago, I swapped a swap meet 3310 (rebuilt and tweaked by me beforehand) for a jetted and powervalved 650 DP on a basically stock 383. The owner didnt believe me, so I had him make several passes before I switched them. The car went from 14.8 @ 92mph to 14.1 @ 95 with no other changes. The 60' only had a .01 improvement..it was all in the smooth application of the secondaries, as oppose to a second large accelerator pump dumping excess fuel, and the engine then recovering from it.