5.7 0r 6.1 with msd hemi 6 and carb

Swifter,

I think if you read the attached article posted by Joe Boy, you'll see that the plastic 5.7L Hemi manifold had between 10 and 40 HP advantage over the single plane MP manifold from 4000 to 6000 RPM. Only at 6500 RPM did the single plane MP manifold begin to make more power, and then it only made 6 HP more. In terms of torque the power gains were even more substantial, again the single plane manifold only gains an advantage beginning at 6500.

As far as a carb being the "worst" thing you can do to a hemi, that is clearly hyperbole. I think a more accurate description of a carb on a modern hemi is that if you choose to go that route your leaving "free" HP on the table.

At one time carbs had a distinct advantage over fuel injection particularly in race applications. I think fully programmable fuel injection setups have negated that advantage. In my view here are advantages of modern port fuel injection.

1. Fuel injection manifold design considerations only have to balance port cross section for sufficient air flow and velocity. While carburetor manifolds also have the challenge of ensuring that fuel stays atomized, carburetor manifold designers have to worry about fuel dropping out of suspension and creating lean cylinders and the resulting loss of power. This advantage of a dry manifold can be clearly seen in the Eagle 5.7l hemis, they have variable intake runner length, this allows a truck hemi to have 390 HP and 400 Ft. Lbs. of torque out of 345 cubic inches.

2. Carbs have to be sized small so that engine vacuum can send a signal to the carb, while fuel injection motors don't need to rely on a strong vacuum signal to the carb. Fuel injection can be programmed to respond to a very weak manifold signal. The result is carbs for a 5.7L Hemi range in size from 625-750 CFM. Any bigger and the motor would be a dog on the bottom end. All Hemis come with an 80mm throttle body capable of flowing over 900 CFM.

3. At one time a big advantage that carbs had over fuel injection was that you could run a lot bigger cam with a carb than you could with fuel injection. However if you go to fully programmable fuel injection that is capable of Alpha N programming you can run as radical a cam as you like.

All that being said, I've moderated my views regarding carbs on a modern hemi. I still think EFI is the way to go, but I've seen too many very nice running GenIII Hemis with carbs and owners who are completely happy. Who am I to look at someone completely satisfied and say they're wrong?

Regards,

Joe Dokes