How much timing can it take

[plymouth1937]

Been fidling whid the timing on my 400bb now im at 18° initial and 42° total no vacuum it has a prutty stout cam i dont knowe the specs but it sounds helty and yes its a low comp engine iv decided to stop at this point,no pinging and stady at 180°f when crusing,any body gone fader than 42

 

[67Dart273]

You are already in the danger zone. Start by determining if your marks are accurate, aka piston stop

 

[318willrun]

depends how low the compression actually is...... I run my 318 at 20* initial and 40* total. No pinging, performs the best, starts great. Been this way for about 6 years now. However, if you are at 42* total, sounds like you are at the upper spectrum. If I were in your place, I'd see if it liked a couple more degrees of INITIAL, curve it all in by 2800 rpms, and set the total to about 38* and see how it likes it. FBO plate is your friend.

 

[RustyRatRod]

The 18 initial is ok. That 42 total is too much. you need to limit total to about 32-34 on a big block.

 

[33IMP]

42 is pushing your luck, imo, but maybe okay with a 7.5-8.5 engine.
With quite a bit more compression, mine runs best at 38, but 36 is safer, and runs nearly as well with less worry about detonation.

 

[plymouth1937]

Ok thanks for al the input

 

[Bewy]

Have you tried this [ you should do, if not done]: engine idling, rotate dist for highest idle rpm. For a low comp engine with a stout cam, I'll bet is a LOT more than 18*....
Report back.