Big block exhaust valves

What size exhaust valves are being used in most high horsepower big blocks (non-Hemi) nowadays?

Depends on the heads? 1.81" is pretty common size for larger than stock exhaust in most heads.

The Trick Flow 240s and 270s are using a 1.76" exhaust valve.

It depends on which heads your going to use, stock 1967 and later Hi Po iron heads had 1.74, Eddy RPM and other after market Hi Po aluminum heads have 1.81 and some of the B1 heads have 1.76
Indy SR and 440-1 have 1.81 exhaust size also

The old 426 Stage III had 1.88’s. How come those are not being used in the race heads today?

As mentioned, depends on the heads. A smaller exhaust valve leaves room for a larger intake valve.

Correct me if I'm wrong didn't the 426 notch the top of the cylinders a little on those because the 1.88's got too close? I know we had to on my 383 with 1.88s (Same basic 4.25" bore) This is one of the reasons I wont consider 1.88s, not worth the aggravation plus not much benefit.

[quote=Jwilli500]Correct me if I'm wrong didn't the 426 notch the top of the cylinders a little on those because the 1.88's got too close? I know we had to on my 383 with 1.88s (Same basic 4.25" bore) This is one of the reasons I wont consider 1.88s, not worth the aggravation plus not much benefit.]

You are correct on the larger 1.88 exhaust valves in the 4.250 or smaller bores

Put your heads on a non chamfered .030 over bare 440 block, turn it over and tell me what you see. Even some 1.74 heads could benefit from a small notch. When machine shops put 2.14-1.81 valves in they usually unshroud the head making it worse. Put heads on block, turn over, scratch bore circle on head, mark heads left and right, tell shop do not go past this line, if they do you need a notch, unless a ledge in the flow path helps, it may I do not know but doubt it.

I might add, a felpro 1009 headgasket used as a template to scratch the head before a valve job will need a small notch if they unshroud the head out to the gasket line, an 8519 pt will need a little more, it is just what I have seen looking up thru the bores. Some 400 blocks with the hugh chamfer are good to go. The 1009 is a good template gasket in my opinion, simple notch job.