I just verified my timing and it looks fine.
Hooked up a vac gauge to the manifold and got 15-16 hg at 850rpm idle.
Seems like I read it should have 18-20 and be steady.
What is the most likely cause of this?
Any trouble shooting tips?

Thanks

 

is the motor stock or ? also what carb do you have
did you adjust the mixture screws ?

 

Mostly stock. Flat top pistons. Erson mild cam.....484 lift and 214 duration.
No valve train noise and no notieacable huge issues.

I do suspect my distributor of being crap but verified timing is close.

Edelbrock 600. Did adjust the screws at rifle but only briefly.

 

The slightly low vacuum is probably because of the cam. With those specs it should have a reletively smooth idle. Just slightly lumpy. I am guessing that Erson cam has a dual pattern Lobe Center. Probably like 107 degrees and 117 degrees. What ever it's specs are a general rule of thumb is the more the Lumpy a cam is the less vacuum siganal will be in the intake manifold.

 

OK thanks for the info. I'm really trying to eliminate possibilities. My motor starts and runs fine.....but isn't making any power.

 

I think it's in that Dizzy also. It is always best to fix what you know is broke 1st. Then move on. Get a new Dizzy so your timing marks won't jump around. Timing of when those plugs fire is HUGE towards power.

 

Well I got another timing light on it and verified timing was consistent but I didn't check if the mechanical or vac advance was working or how good the coil is. I've take. That dizzy out before and had the shaft be very hard to turn. I'm replacing all that this weekend and if that doesn't help I'm gonna compression check all the cylinders and go from there.

 

Good Plan.