Detonation stumping me

[gtca9014]

I rebuilt a 351W with AllPro heads. Ran fine before. He ran it hot and warped the heads. Bored, cut .015 off heads to straighten, put rest together as came apart with .045 deck clearance. Didn't detonate before at 34 degrees total, 16 initial and vacuum advance. Now at part throttle above 2000 it pings horribly with 30 degrees total and no vacuum advance (unhooked it testing). Car sat for 1 year so I thought maybe it was gas. Added octane boost, ran that tank out and many others driving easy. Plugs look slightly lean but not extreme and it ran jetted like this before. Thinking may have vacuum leak somewhere but haven't found it. Couple thoughts:
1. PCV valve is teed into brake booster line- is this correct? Don't remember if this was the way it was before. Could this cause problem?
2. Could a vacuum leak from intake into lifter valley cause this issue? How do I check for that? The intake was not cut, should it have been with .015 off the heads?
Need to get this thing out of my life, any help would be appreciated.

[travis]

I have never seen a PCV tied in with the power brakes. Is this normal for whatever your working on?

Although I have never checked, I always thought the pcv vacuum was considerably less than full manifold vacuum. Are you sucking oil out of the valve cover? How about removing the pcv from the equation and see if that helps?

[Firedome8]

No the pcv valve needs full manifold vacuum preferably off the base of carb not a manifold runner. The power brakes can run off a single runner.

[gtca9014]

I have never seen a PCV tied in with the power brakes. Is this normal for whatever your working on?

Although I have never checked, I always thought the pcv vacuum was considerably less than full manifold vacuum. Are you sucking oil out of the valve cover? How about removing the pcv from the equation and see if that helps?

Im not sure, it was built originally by someone else. I plan to reroute the hoses to eliminate this but was wondering if it was normal as is?

[gtca9014]

No the pcv valve needs full manifold vacuum preferably off the base of carb not a manifold runner. The power brakes can run off a single runner.

It is at base of carb, 750 vac secondary Holley, under vacuum secondary diaphragm. The brakes are teed into this port also.

[Kevin Johnson]

Check the booster diaphragm for a leak.

[mag2555]

How much can you choke off the Carb before the motor stalls?
This test will give a clue if you have a vacuum leak or not.

[hondo383]

Oil getting into the chamber?
From warped intake flanges...or cooked rings

[gtca9014]

Don't see any oil on plugs, rings are new. Compression check is 180psi +/- 15psi. I forgot to choke it out before pulling plugs, I will try that this weekend.

[BOOT]

Try thicker oil, chased a det problem in a highish mileage engine(kinda same since it was ran hot) and all it needed was to go too 10w40. Can't rem if it was just one oil change or a quick 2nd.

[Newold1]

How many degrees of vacuum only advance is set up in the distributor? You mention 16 degrees initial but you mention that when run at 30 degrees with vacuum advance not connected. I am assuming this means there is 14 degrees of mechanical advance in the distributor. So if there is more than 4 degrees of vacuum advance you are seeing over 34 degrees of advance if I am understanding what you have and are describing.
Most vacuum advances I have seen have more than 4 degrees total advance in the unit.
Something here is not working for me?
Am I understanding your description correctly.

Have you checked and verified the TDC timing mark on the damper to see how it corresponds to the piston TDC?

[Neal Arnold]

351W with AllPro heads. Didn't Know Bob made Ford heads??

[naukkis79]

Will it ping if you add plenty of vacuum advance, something like 45 degree total timing?

[JoePorting]

Can't you just retard the timing until it stops pinging? Sounds like you set the initial timing at 34 degrees. Just set it back to 14.

[My427stang]

Any chance you have a head gasket on backwards and the back of the block is hot?

I'd expect it to overheat, but just tossing ideas around