I got the math blues... reading hurts your brain.

[BOSSMAN]

That LS3 head responds to a better valve job, a little chamber work, and bowl work really well. You can gain 40-50 cfm pretty easy on those.

[DanStokes]

It's great to hear Nick bring up choke flow (as we called it at EPA). I've tried to discuss this with a few hot rodders over the years and they mostly refuse to believe in the concept. Truth is, there's only so much air that you can stuff thru a hole of a certain size and the question is does the engine want more than that.

Dan

[MR P-BODY]

I would call 300 ft/sec a "happy safe" number. Some engines may like as low as 250ft/sec and on up to near sonic choke at 350ft/sec. Alot of the Stock and Super Stock heads are borderline sonic choke cause they are required to have a poured stock volume that limits what you can do. A newer head like the LS3 for example may be in the 270 ft/sec territory. That's where people like myself have to sit down and calculate "targets" for a given combination. I base alot of my work off of these calculations and tweek from there until I'm satisfied with the results. Wallace Racing, Stan Weiss's Website, Pipemax, Dynomation, and some personal Excel Spreadsheets are what I typically use to get a feel for an engine's specific need. Problem is you can dive even deeper with calculations from an engineering point and that is where your head starts to spin!

Yeah I use the Pipe Max alot for this type of data

[quick 52]

I would call 300 ft/sec a "happy safe" number. Some engines may like as low as 250ft/sec and on up to near sonic choke at 350ft/sec. Alot of the Stock and Super Stock heads are borderline sonic choke cause they are required to have a poured stock volume that limits what you can do. A newer head like the LS3 for example may be in the 270 ft/sec territory. That's where people like myself have to sit down and calculate "targets" for a given combination. I base alot of my work off of these calculations and tweek from there until I'm satisfied with the results. Wallace Racing, Stan Weiss's Website, Pipemax, Dynomation, and some personal Excel Spreadsheets are what I typically use to get a feel for an engine's specific need. Problem is you can dive even deeper with calculations from an engineering point and that is where your head starts to spin!

when all else fails use bar math

[MR P-BODY]

Ahhhhhh, now we are making progress. It would be nice if they published minimum cross sectional area information. Instead they've started giving us port volume. A large volume with a small pinch point, is all about the small pinch point.

Mr. P...stuff you've read, or stuff you know?

Both... I talked to alot of the head guys (head lab at work) plus seeing
those results on my own junk.... the 300fps is a pretty decent number
but I'm sure there is some variance in it(one number never fits all)