what size carb do i need?

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daves 72 dart

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What size carb will i need? I plan on shifting at 7200 rpm's.The specs on my engine is 1972 340 block
Work done: O-ringed, tubed for roller cam, oil gallies enlarged, bored to 4.07
(.030 over) and honed with deck plates by Herb McCandless.

340 steel crank
Prepared by Lunati, stroked .110 to 3.42 stroke and balanced to 8000 rpm's.

340 steel rods
Prepped by Lunati. Hand picked set. All are within .001 of each other in length. Bronze bushed, balanced and lightened.

Heads
340 X heads with 2.08 intake valves and 1.60 exhausts. Double springs for
.700 lift cam, Maximum porting on intake and exhaust ports.Ports are 63cc combustion chambers.

Pistons
Venolia lightweight forged pistons. Uses dykes top ring, 1/16 2nd ring and standard tension oil rings. Weight is 510 grams.the Compression is 11.3

Intake
Holley Strip Dominator ported to match heads

Camshaft
Cam Motion roller 269 275 @ .050 and .631 lift with 1.5 rocker Valves set on .024 .028
RPM range 4500-7500. Cam is degreed in at 104 deg centerline.

Other Parts
High volume Melling oil pump, Comp Cams roller lifters, Crane 1.5 roller rockers(gold), Fluid Balancer, windage tray, Cloyes double roller timing set. SCE copper head gaskets(.060). Tall valve covers for use with roller rockers. Moroso 8 qt deep sump oil pan. Bronze cam gear for use with roller cams.
 
daves 72 dart said:
What size carb will i need? I plan on shifting at 7200 rpm's.The specs on my engine is 1972 340 block
Work done: O-ringed, tubed for roller cam, oil gallies enlarged, bored to 4.07
(.030 over) and honed with deck plates by Herb McCandless.

340 steel crank
Prepared by Lunati, stroked .110 to 3.42 stroke and balanced to 8000 rpm's.

340 steel rods
Prepped by Lunati. Hand picked set. All are within .001 of each other in length. Bronze bushed, balanced and lightened.

Heads
340 X heads with 2.08 intake valves and 1.60 exhausts. Double springs for
.700 lift cam, Maximum porting on intake and exhaust ports.Ports are 63cc combustion chambers.

Pistons
Venolia lightweight forged pistons. Uses dykes top ring, 1/16 2nd ring and standard tension oil rings. Weight is 510 grams.the Compression is 11.3

Intake
Holley Strip Dominator ported to match heads

Camshaft
Cam Motion roller 269 275 @ .050 and .631 lift with 1.5 rocker Valves set on .024 .028
RPM range 4500-7500. Cam is degreed in at 104 deg centerline.

Other Parts
High volume Melling oil pump, Comp Cams roller lifters, Crane 1.5 roller rockers(gold), Fluid Balancer, windage tray, Cloyes double roller timing set. SCE copper head gaskets(.060). Tall valve covers for use with roller rockers. Moroso 8 qt deep sump oil pan. Bronze cam gear for use with roller cams.
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A lot of guys will tell you to go bigger but going by the numbers all you will need is a 750.
 
holley street avenger 770 and change the spring to the yellow one the give u with the carb..then beat the hell out of the car....lol
 
stay away from a vacuum secondary carb. If it was mine, I'd go with a 850dp holley. a 750 might work, but I believe that you'd make more power with the 850. My 2 cents.
 
Taking the specs given, anywhere between a 750-850 cfm carb should work fine. This is using the 7500 rpm as the max working rpm. This is my 2¢ worth.
 
Holley's website recommends 750-850 cfm.

I entered the following data...

355 CID
7200 RPM
highly modified engine
double pumper, manual choke, for race.

With the amount of work you have into your motor, I would seek the advice of a carb expert, i.e. Barry Grant or maybe a forum member can make another recommendation.

http://www.holley.com/applications/CarburetorSelector/CarbSelection.asp
 
If you add up all the 2-cents worth answers you get, you may end up with half-a-buck! My 2-cents also says go with an 850cfm carb on this combo. I ran a highly modified 340 on the street years ago in SoCal and a Holley 750dp couldn't keep it fed. Had to go to an 850dp to keep from running out of fuel on the top end.
 
I agree, 750 to 850 should work

What about gears, converter, tire size and weight ?
 
I run a 750 on my 340 stock stroke 0.30 over with ported J heads and its plenty and im down in the low 12's
 
I have a great Holley 1050 that is rebuilt and ready to bolt on...
 
thanks everyone.This is going to be a strip/street car not a daily driver.i dont care about street manners.but it will see some street time to eat some rice. hopping to get it into the 11's. then i will get kicked off the track for not having a roll cage. KSP 1050 is a little to big right. but how much are you asking?
 
AdamR said:
I agree, 750 to 850 should work

What about gears, converter, tire size and weight ?
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My dart has 488 gears. i have not got the converter yet.Im thinking 3500 to 4000 i still wood like to drive it on the street .the tires are going to be either 28 or 29 and i dont know the weight yet.im thinking from 3000 to 3300.
 
I would run a 800 double pumper on it. Your going to need way more then 3000rpm stall. More like 5500.
 
Your set up is similiar to mine. I am running a 750 with a proform center section upgrade. If you already have a 750 kicking around, you can buy a proform center from Summit for about $ 130 and what a difference, they flow some nice and bringing your cfm somewhere between 830 - 850.
 
340 swinger said:
Your set up is similiar to mine. I am running a 750 with a proform center section upgrade. If you already have a 750 kicking around, you can buy a proform center from Summit for about $ 130 and what a difference, they flow some nice and bringing your cfm somewhere between 830 - 850.
Click to expand...

what times are you runing with your dart?im hoping for 11's.
 
I'd go at least 800cfn, and I agree with Adam. It's goign to be soft down low anyway. Aim for 3800 brake stall, 4500 flash, and it should be livable on the street with the right gearing. Which would be minimum 4.30s with a 26" tire.
 
I ran a Turbo Action tight 8" converter on the street for a year with no problems. It flashed to about 4200 and actually drove nicer then the cheap 10" converter it replaced.
 
Thrashard340 said:
I was thinking 4000+ rpm stall. What's the RPM range on the cam?
Click to expand...

rpm range on the cam is 4500 to 7500 Camshaft
Cam Motion roller 269 275 @ .050 and .631 lift with 1.5 rocker Valves set on .024 .028
RPM range 4500-7500. Cam is degreed in at 104 deg centerline.
 
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