"big" cam on 390 timing???

Hi fellas im new to the board a lady in my neighborhood saw my wagon and refered me to the site. great site by the way!
Anyways...
i have a 1965 ford country sedan, has a new engine installed by the P.O. he says he changed the cam to a 270??? he said he wanted the largest cam he could get while maintaining an idle. i dunno.
anywasy my question is where should i time it at? oviously not stock correct? more advanced more retarded like the P.O. LOL
or just rev it and time it by ear? it also has a c-6 which replaced the good ol cruise o matic and a mini spool which i hate. anyone wanna trade third members? anyways if anyone can suggest something i would appreciate it...
Raf-
here she is

Never Time by Ear !!!!

You need to Put a timing light on it.

Start at the factory specifications and move it around for best performance.

well i do have a timing light, but on the oem spot it runs like crap. if i move it little by little it might as well be by ear if theres no limit right? i forgot to mention it also has a pertronix ignition module

No, Use the light. You need to know where your at, if it goes to far you may have an issues with something that needs fixed or is wrong.

ok so i start at factory line, and then advance or retard what an 8th of an inch, see my point. or say "advance about that much" theres no way of tellin how many degrees ive gone. right? im not disagreeing with you im just confused what do you all do?

You have timing marks on the balancer and a pointer by the balancer. Mark the 0 notch on the balancer with some white paint. and then mark the factory recomended line on the balancer for a 427 MR motor with some white paint.

Use the timing light while you turn the distributor until the mark you made for the 427 factory timing lines up with the pointer.

so you say oem settings are ok for a bigger cam.
thx

Raf

The Balancer should have mark's on it in Degrees.

The 30 degrees is total all in by the advance in the distrubutor, thats a different issue, you are trying to set initial first (should be between 8-14 degrees) and then you will play with the total advance.

You will set the initial timing with the vaccum to the distributor disconnected and plugged.

Let me look and see what I can find for factory timing

In a car with a cam like that that you are trying to ime, you should use a vacuum gauge to time it.

It's really easy, just put a vacuum gauge on a nipple getting direct manifold vacuum.

Start at about 10* advance with the car all nice and warmed up.

Advance the timing until you reach the highest vacuum reading (it will reach a point where it will won't be steady anymore, so back off the timing until it the vacuum drops a little and strady's out).

That's about where that cam want's to be run. Not that it's 100% the right way, but it works.

FE

Factory initial for a 1967 Mustang 390 calls for 6 degrees.

What Distributor are you running?