Help me here guys my mind is a little numb from all the cold. Roots blower fuel distribution standard rotation the rear cylinders would be richer for the most part providing of course the tune up is close to start with. Correct?

From what I have read usually concerning B&M 250's is that they are lean up front and that they actually produced an offset carb plate to help correct the issue.
#93153
http://www.holley.com/data/Catalogs/Weiand/118.pdf

Thanks Rookie. Yea I knew the single carb smaller blowers had the issue but I am thinking more in terms of 8-71 and larger with 2 carbs. Anyone else?

It's been awhile since I messed with that kind of blower but I think you are correct on the standard rotor being richer in the back.

Are you sure this isn`t an old wifes tale brought over to the marine world from drag racing?
Fuel does get pushed back in a drag car due to the forces involved in acceleration but is it that same for a boat?

Ive never noticed any color difference in plugs from front to rear this summer I was checking plugs every weekend.

I believe on a twisted helix GMC style blower like an 8-71, the fuel/air is pushed towards the front, making the rear cylinders leaner.

Thats only half the battle with these style blowers. Not only is the front to rear distribution crappy, the side to side is also. I've seen the AFR from bank to bank vary as much as .5-.75 from the odd to the even bank, especially at lower rpm. Compared to my straight two lobe 420 B&M, fuel distribution wise they kinda suck. Running an 02 on each bank, my afr's have always been very close to each other.

You can try and play with staggering the jets, but thats only gonna get you so far. You'll end up having to live with it, kinda is what it is. Thats why these setups need to be quite a bit richer than a comparable port injected setup, or a screw blower.

Wtf!!?? UCDEDPPL No Dudes!

I agree, just not right for this site! Maybe he has the Avatars mixed up from one of his other frequented sites!!! "Did I just say that ?" Just Kidding Dan.

Ok Ok everything is back to normal lol

Thanks