Lots of talk across the net says the st bottom end is good for 350 max. But for every one saying it was reliable at 350 others will tell you it let go below 250. There are so many variables. Despite what people will tell you neither the rods or pistons are what you would traditionally call forged.
one thing the st pistons don’t like is Det’ the ring lands seem to let go.
The head is much better flowing than a Blacktop but you will never exploit it with standard pistons and the blacktop head saves messing about with the vvt. You still won’t reach its limits on standard pistons.
Mines built and being fitted, we will suck it and see this summer.