timming trouble???

I have a stock chevy 350, running a edellbrock rpm cam and intake and 750 cfm carb, hei w/vac advance. timming checks at straight up at idle, but have low power when driving....any sugestions...it may be the carb but i have been out the game for awile.

 

Try 10 - 12 deg BTDC. Carb would be better at around 600 cfm.

 

What's your max timing? Can you better explain "timming checks at straight up at idle?"

 

You're right! I was just ***uming that he meant 0 Deg @ TDC. (Shouldn't ***ume)

 

I agree--that's a lotta carb

 

Y, carb raised my eyebrows. Ditch it for a 600.

Be sure to check your timing when all advance has dialed in, also. You should see 34-38 degrees above 2500-2800 rpm. Maybe 3000 if it comes in later. If not all in by 3000, either the advance mechinism is jacked or you don't have enough initial timing. Recurve may be in order.

 

Everybodys right here, timing and too much carb. A 600 will feed that with no problem .

 

Not trying to be a jerk, but you are disconnceting the vacuum advance and plugging it right?

If you have a dial back light or degreed damper you can rev it up and set the light to read 36 degrees with it advanced, and then check your static, it will tell you how much the dist is advancing.


10-12 is a good start for static.

for a stock 350 a 600 is a good carb, vacuum secondary, although a 750 vacuum advance is not going to cause major issues, your low end power will not be as crisp as it would be with a 600, but get the timing down before you play with the carb..

fwiw I have a 030 350 with a edelbrock dual plane and a 750 vac sec.

Just put in a single point dizzy in last night, total timing is 36 degrees at 2600, with 12 at the crank (static) all with the vac plugged.

 

Low power compared to what? Before the too big cam, intake and carb were put on it? Is it in a heavy truck? A light roadster? Stick? Auto? Way more info needed to help you.

 

Pretty sure we dont have enough info to really help this guy.

is it a stock 350 with 350,000 miles? if its wore out its not gonna have any power.

what gear does it have? a 2.50 gear and a tall tire will have it acting like its got no power.

 

Make sure to set your timing with the vacuum advance unplugged from the distributor. MANY times, I see vacuum advance hooked up to manifold vacuum instead of ported vacuum. Your vacuum source should be ABOVE the throttle plate and near zero at idle, increasing with RPM.
Manifold vacuum is highest with the throttle closed and drops to zero when you stab the throttle (the opposite of ported vacuum).
If you're hooked to manifold vacuum and THEN set your timing, your car will be a snail.

 

PS- run as far advanced as you can until the engine pings under load, then back it off a couple of degrees.