vacuum for mopar 509 cam....

[Charger_Dart]

FWIW I have a 509 cam in my big block and it only pulls about 8-9" of vacuum at idle - about 950 - 1050 rpm

[c00nhunterjoe]

FWIW I have a 509 cam in my big block and it only pulls about 8-9" of vacuum at idle - about 950 - 1050 rpm

My 383 does NOT like to idle that low... lol. I will have to try to force her to idle below 1000 and get a reading...lol

[Kern Dog]

If your gauge reads 21" of vacuum with a 509 cam in a 440 at less than 1000 rpm, your gauge is broken.

Absolutely. I had a 509 in my 440/493 and the best idle vacuum in Park was 11" at around 1100 rpms.

[Kern Dog]

"Point being this guy told me my engine is messed up and my vacuum should be at 15 to 20?   I was like oh crap really? He said I need to retime my car for higher vacuum amd he said I should haveore power.  I told him my engine has 500hp on engine dyno stand.....with that vacuum.   He said if I could get more vacuum I would have a 900hp engine?"

That guy is a delusional assclown.
There is no way in any universe that any amount of tuning or timing adjustment is worth 400 HP. What a jerkoff.
Now, it is entirely possible to see decent gains in the 25-30 HP range if the baseline timing is at a paltry stock 6* BTDC and the engine "likes" 18-20*. The 509 with the long overlap does need a bunch of initial to overcome the dilution of the intake charge. My 440/493 ran about 10-11" of vacuum with the 509 at a 1000 rpm idle.
People bash the MP cams for being outdated but they DO make power. I haven't heard nearly as many cam & lifter failures from Ma Mopar as compared to the likes of Comp Cams.

[b5blue]

 I had a Mopar 509 in my 70 Charger (440) and lived with it 15 years as a daily driver. It took some tweaks to get it to behave well with my six pack and as mentioned off idle not much torque. It's basically a drag race grind and from mid range up pulls like a beast. Adjust and live with it until you can get a street grind in there.