Mopar Muscle Association UK

The calculation I have always used is cubic inches multiplied by the maximum RPM and divided by 3456

T'as always worked for me

BTW this assumes that your motor is 100% efficient, if you added a factor of say 85-90% you'd end up with a smaller carb....

I have successfully run a 12 with a 650 DP on a 383

The object of the excersise is not to run your best with the smallest carb, its to run your best with a carb that will achieve the best ET, that will all depend on what you have inside your engine, your gears/trans/verter/tyre size, and rpm that your motor makes it max power at.

The proof is on the track, not in books and formulas. Everyone kept telling me that my 850DP was way too big for my 340 motor when I was racing, well I proved them ALL wrong, the car would go 2/10ths SLOWER with anything smaller than that 850. If you input my figures into the formula of engine size, 340, max rpm 6800 and a VE of only .90, you get around 602cfm....yeah!......your giving away ET.

Jon has asked for recommendations based on a 'car is on the road 99% of its life' not what gonna get him down the track quick.

I am merely illustrating what has worked for me with what looks like a similar combo in a similar car

dustymopar wrote:Jon has asked for recommendations based on a 'car is on the road 99% of its life' not what gonna get him down the track quick.

I am merely illustrating what has worked for me with what looks like a similar combo in a similar car

Yes and I have given my opnion on what would work ok for his street car previously, I was merely referring to your comment about what you ran down a race track with a 650DP carb which has nothing to do with the street

Les

For the sake of shelling out 300-400 of yer Earth Pounds I'd take up Jon Connoly (nicest bloke you'll find) very kind offer and at least isolate any other probs, low fuel pressure, shagged pump, etc

Adrian Worman wrote:For the sake of shelling out 300-400 of yer Earth Pounds I'd take up Jon Connoly (nicest bloke you'll find) very kind offer and at least isolate any other probs, low fuel pressure, shagged pump, etc

tried to suggest that before. re PoE

Les Szabo wrote:

Adrian Worman wrote:For the sake of shelling out 300-400 of yer Earth Pounds I'd take up Jon Connoly (nicest bloke you'll find) very kind offer and at least isolate any other probs, low fuel pressure, shagged pump, etc

tried to suggest that before. re PoE

I know you did Les, agree with you entirely
Just thought it was worth repeating

Les Szabo wrote:

Adrian Worman wrote:For the sake of shelling out 300-400 of yer Earth Pounds I'd take up Jon Connoly (nicest bloke you'll find) very kind offer and at least isolate any other probs, low fuel pressure, shagged pump, etc

tried to suggest that before. re PoE

PoE?

Guys, I am grateful for the offer of loans.

The carb (all bit it not the only thing perhaps) is faulty. The float stick to the floor even with a bowl full of fuel.

Instead of shelling out more parts on this carb, I am buying a new carb.

I've had an electric pump on the car - it does the same thing.

I've had two gauges on the car and the fuel pressure shows the same.

I hope its only the carb but part if not all of the problem certainly is the carb. No point in me borrowing a carb, setting it up (ish) then ripping it off and doing it all again.

GJUK wrote:The float stick to the floor even with a bowl full of fuel.

it'll be something really simple.

can't hurt to take a close up photo of the inside of the float bowl and post it on here.

Bozwell wrote:

GJUK wrote:The float stick to the floor even with a bowl full of fuel.

it'll be something really simple.

can't hurt to take a close up photo of the inside of the float bowl and post it on here.

I'm away at the moment with work but will do tomorrow Thanks.

Bozwell wrote:

GJUK wrote:The float stick to the floor even with a bowl full of fuel.

it'll be something really simple.

can't hurt to take a close up photo of the inside of the float bowl and post it on here.

I agree.
I have recently heard of a similar problem due to a defect in casting. Suppose as things get older and looser more chance of snagging.

Mossy68 wrote:

Bozwell wrote:

GJUK wrote:The float stick to the floor even with a bowl full of fuel.

it'll be something really simple.

can't hurt to take a close up photo of the inside of the float bowl and post it on here.

I agree.
I have recently heard of a similar problem due to a defect in casting. Suppose as things get older and looser more chance of snagging.

I've just looked on RealSteel and the casings are about £50. Then I would have to get new flaots £15 each. So you're in for just under £100 posted.

1/4 of a double pumper new price.

Or a dremel to your float bowl !

New parts does not always mean good parts in our Mopar world unfortunately.

Here are some photos of the float.

Tell me if you see something obvious.

I can't. Apart from the slightly bent float. The needle still sticks when dry, you lift it up and it sticks closed, but perhaps thats due to no pressure behind it.

It just sticks to the bottom sometimes.