B&M 420's
 

Possibly looking to upgrade over the winter from my 250's. Anyone have a pair of 420's collecting dust on a shelf? Needing from the blower to the flame arrestor. Thanks!

Soooo, What are your plans for the 250s?

If I can make the right deal on some 420's the 250's will be up for grabs - less intakes.

I have three on my boat now, was thinking of going to 10 71's. Carbs are primary & secondary boost referenced. Blowers were rebuilt & stripped 54 hours ago. If you PM me a reasonable offer I am game.

Who did the work on them?

Turning up the boost? :cartman:

how well would the 420's work on my 540's if I pulled the EFI

8/10 series for volume the 420s would be working almost to there max volume

an 8-71, is 436 CID, and a 10-71, is 469 CID. A 420 B&M is 420 CID, 250 B&M, is 250 CID. A 177 weiand, is 177 CID.

I have seen 420 B&M builds make 1000HP on pump gas builds. A 420 on a 540ci, making 8lbs of boost, will still be much less overdriven, than a 250 blower, on a 454 making 5lbs of boost. Swapping from a 250, to a 420, is a huge jump in displacement. Going from a 420, to an 8-71, is not much at all.

I would take a 420 with strips way over a 8 71 without strips