1984HO

iTrader: (1)

hey guys i recently installed a rebuilt l05 in place of my 305 in my 84z28 anyways heres the specs

stock compression
ported 193 heads w comp 981 springs
roller cam conversion with lt1 cam
melling m55 oil pump edelbrock performer intake
holley 600 cfm carb

no i realize this is carbed and not tbi

that is my problem all the search results were for tbi cars
so my question is what should my base timing be at in a l05 with lt1 cam CARBURATED engine ?? i have it a 4 now but thought maybe 6 or so would be better but i read as high as 8


PLEASE help

Fast355

iTrader: (2)

First you need to know where your distributer stops adding centrifical advance. If it is stock, it is around 4,000+ RPM. You want 28-30* total advance all in by 3,200 or so. Stock HEI distributers typically give 22-24* advance, that gives you 4-8 BTDC. I would start at 4*, then work up. Don't trust the butt-o-meter for timing adjustments. Go to the track and play with it, watching trap speed. I like to make 1* increments starting from least advance to most advance. My 279 RWHP LT1 cammed, ported swirly head L05 liked 29* BTDC @ 2,700 RPM.

1984HO

iTrader: (1)

not stock i have an advance kit in it (dont remebmer which) my timing light isn't advnace capable either so i gues ill have to play with it

what did your car end up requiring for base timing ?? also what did it run in the 1/4 ??
this engine is like all torque yikes pulls pretty well up top though but with the 700 r4 and 3.73 i can spin the tires all the way through first then get pretty loose into second NOT THAT I WOULD KNOW

Fast355

iTrader: (2)

Well it was still TBI and it was in a Fullsize Van(700R4 w/2,000 stall, 3.08 govlock, and P255/70/R15s). It ran a 15.6 @ 88 into a 20 MPH headwind, the crank gave up before it went any deeper into the 15s.

I was running around 14* base timing with a pretty flat curve, peaking at 29* BTDC @ 2,700 rpm. You would have to get access to a distributer machine, weld up, and grind your centrifical advance limiter stops to get around 14* mechanical advance to do the same. Then you could set your base timing at 14-16* without going over 28-30* total advance.

kdrolt

Just remember that those heads, even when ported, have such good burn speed that they don't want, or need, a lot of ignition advance to make optimum torque and power. That's why Fast355 said not to go over 28-30* total advance.

You could also use a stopwatch and a patch of flat straight police-free road having two landmarks from which you could do some time-to-distance measurements. The idea is to take several runs, reset the ign advance, and then test again.

Have taken the car to Epping yet? I think it's the closest track for you.

1984HO

iTrader: (1)

yeah epping is the plan but all this new found power seems to be acclerating the eminent(sp) demise of the ole' 10-bolt hehe so epping is about 45 minutes away all highway.... so well see i have it set at 4 degrees right now
i have a fuidamper so it has the marks on it so im gonna mark of 30 degrees hook up the timing light and rev it up to see what the advance is @ 2000 and 3000 rpms