to notch or not to notch the block

how many of you do? how many of you don't? i'm talking about notching the top of the bore for unshrouding the valves?

Now I know why my pig won`t run. Mine wasn`t done not even sure it would help my car w/a 2.14 intake.

I am running a 4.375" bore and 2.25" intake valve, without "notching" the bore. However, a 1/8" down "blend" could be a worth considering. I don't want to get anywere near the top of the ring travel. It may be more important to look at the combustion chamber "eyebrow" to blend to the cylinder.

I just notched the cylinders on my 511 on the intakes, also the heads a little. The 2.30 intake valve I figured could use it on the B1 heads. I didn't go nuts but a decent blend in the eye brow.

I won't get any accurate numbers to see if it helped as I won't put it back on the chassis dyno, gonna go to the engine dyno this time. My only track outing didn't go well last year.

I do I would also include clearencing the head chamber at the valve eyebrow to match.

I consider it part of the finishing port work of the heads and block and the entire air/fuel flow path. Even with a 906 head with a 2.08 valve one can see the benefits of this IMO

Just do a before and after "notching" visual look of the head mounted on the block with a intake valve fixed at .500 lift or so. As Viewed from the the crankshaft side of the engine.

That should convince anyone IMO, not only that but where you do the Notching, thats very Near the Highest flowing part of the port on the intake side.

Now on the exhaust, Im not sure of the highest flow path, and the valve is a smaller Diameter. So I mostly focus on matching and blending the intake side, and just breaking the sharp edge a little on the exhaust side. mike

I do it on some stuff....