He got it idle low with massive over advance and the fact that it's a big heavy BBC rotating assembly.

To the poster you are or were just destroying the motor with NO thought as to what total advance might be driving down the road. When it fires so far before Top Dead Center on the up stroke of the piston you create massive pressure before the piston can swing over the top. I've had to take apart hot rodded motors that clueless people owned. The main and rod bearings were smashed and worn through the coatings.

Motors that shake, buck, and sound like a race car might impress people with your big cam sound, My solid roller motors idle kind of smooth at 1200 rpm. @ 22 initial and 12 degrees mechanical advance. I also have the vacuum advance limited to 8 degrees. All timing in at 3200 rpm. I use the MSD Etech Dizzy where I set things with electronics and dial switches. No silly weights and springs or installing some kind of advance stop to limit total mechanical advance.

 

And people think I'm crazy for recommending OEM head gaskets and pulling out as much timing as possible on the dynometer. "But it lost 12 peak HP why'd you do that?" I'm saving the rod bearings you fools! Fly!

 

Even the Ford Model A, knew to have a timing retard / advance on the steering column over a hundred yrs ago.
Back then, cranking broke thumbs. Now they break starters.

 

All he has to do is lock the timing @ 36*-38* and it’ll run. At least that’s one option.
Idle, and all in. The intake valve closing is so late that any excess pressure just gets shoved right back out the valve. So all that pressure just gets lost or reduced before the intake valve closes or your 3000 rpm and until peak torque at which time 36* to 38* is what is needed. In order to damage or destroy rod bearings the pressure has to be early on a closed or nearly closed intake valve, otherwise it just turns into reversion and pressure is reduced. Sure ignition takes place after valve closing, but much was lost when the piston started up the stroke so much less to burn to create excessive pressure. Those heads are going to be a low velocity charge into the cylinder below peak torque as well due to their large size. Another reduction in pressure. The heads and cam seems to be a post peak torque power maker set up, not low RPM torque monster where early timing can really do it's damage.

It’s not a street friendly cam. It’s for sustained high rpm running.

didn’t say it’s a good cam for street use, but if you want a decent idle it’s gonna take bunches of advance to get it done. I run mine @36* of advance for idle, however it is with the assistance of vacuum advance. Been that way for 10 years.

two options then use vacuum advance to get the idle timing up and limit the or eliminate the mechanical advance and vacuum advance so as to not over advance at cruise or lock the timing at a set point and not use vacuum any other advance and take the effeciency penalty at cruise.

either which way, it’s gonna take a lot of advance at idle to get it to idle and off idle well.