Timing / advance/ vacumm ?

[TBK1]

trying to figure out some problems, need some input!

Just pulled the mallory unilite dizzy and went back to stock 77 dizzy with vac advance

also added msd 6al box( procomp version)

have timing set at 12 btdc when reved to 3 G get about 31 btdc

(this is with no vacumm on it, ?? Should I hook a vacumm to it and what about straight manifold vac, no other source on trip webers? )

idle set approx 900 rpm

Any inputs???

[jmortensen]

For triple Webers I'd suggest you don't run the vacuum advance. I'd also set the total advance to the mid 30s, as that seems to be where max power is found, usually between 35-38 degrees.

[Carl Beck]

No - you need Ported vacuum to run the vacuum advance. When you go to WOT manifold vacuum drops... where vacuum at the intake ports on a carb. increases. You would have to disconnect the vacuum advance on the 77 Z dizzy - and you need about 17 degrees initial timing.

Webers need lots of initial timing off the line - because of the rich mixture supplied by the accelerator pumps... so something between 15 and 17 degrees initial - then you want a total of about 32/33 degrees all in by 2800 to 3000 RPM. Anything above 32 degrees and I'd bet you'll lose hp - but you have to put it on a dyno to know for sure.

To re-curve either distributor you have to make adjustment to the mechanical advance weights and/or springs. Any good automotive electric shop will have a Sun Distributor Machine and they can re-curve the distributor timing for you.

All of this also depends on the quality of fuel the Federal Government is telling the gas companies they have to sell in your area...

It worked for me...

Carl B.

[TBK1]

Thanks guys will do some tweaking AFTER I take back this pro comp box that took a crap after 1 hour run time!!!!!!!

[TBK1]

Made buy the same guy that made the 6AL MY AIKEN BUTTTTT!