On my bench(the only numbers I care about), it’s a very rare stock J head that flows in the 215 range.
It’s not never...... but very rare for me to see that.
X heads do it, but they are absolutely superior to J heads in terms of ootb flow.
I had one set of factory J’s here, off the same motor.
One head flowed 214...... the other 195.
I’ve tested a few pretty pristine T/A heads..... stock valves and VJ......flowed right around 200.
Ootb unported SM Head flows 250.
Like the heads PBR bought for $450 delivered.
I couldn’t even come close to refurbishing a set of stock heads, and then duplicating that level of flow for what a set of assembled & prepped SM heads would cost.
Even without the heads being on sale, you can have the bare heads and a set of stainless valves delivered to your door for under $800.
Another $200-250 for the remaining parts, $400 labor..... you’re at $1450 prepped and ready to go.
I couldn’t get a set of J’s done, (oven cleaned, magged, all new guides, ex seats installed, machined for posi seals and dual springs, flat milled, and then ported enough to achieve 240+cfm, along with all new parts) cleaned, assembled and ready to bolt on for the same money.
I suppose what one pays will depend on who they’re doing business with...... but at my shop..... prepped SM’s would be less $$$ than “equivalent” J’s.
And if the SM’s were on sale...... then the price spread just grows.
