Highest flowing sbm heads?

Professor Fate said
Since your original question was for a stock block and not a race block, you're already pushing your luck if you're looking to make power in the 600 range.

Nat said
don't I used their bigmouth heads and they do not flow 300+ Most i made with my 426 stroker was 537hp 560 tq which is plenty was able to roast the tires from 60mph , engine is in storage i added a girdle and better main caps for insurance , really for more power
go with a race block stock blocks are not made for 600+ hp God luck with your build

RammerJammer75 said
What about W5s? I can't remember what that flow and I know that they had some issues, but I think they are capable of good power from a stock block.

'68cuda416 said
Yeah you can physically "make it work" but it was a waste of money because you can't reliably make the kind of power the heads can support and the block live.....plain and simple

I love these comments. I have a stock block that runs mid 8's at over 160 in a 3400 pound street car. It has made as much as 1200 at the wheels but its not very tested, it only has 120 runs on it and about 1500 street miles. Then there is my nitrous car that's 372" (14:1 compression) that makes 645 on the motor (flywheel) and I hit it with another 275 of nitrous. But again its not very tried, it only has 300 passes on it and is 17 years old. I must have missed the memo on blocks breaking.

If you can find a set of W5's I highly recommend them. I have been running them for years and will support an easy 700hp. You want the later blue pipe plug version. I think mine flowed 340 cfm intake side and they weren't ported all the way. We need to leave some meat for strength incase of backfires. I also recommend calling IMM engines because he is very knowledgeable about the small Mopar stuff. I have used him for years and his porting is excellent (not to mention his machine work) and he is honest and not super expensive.