On the 4bbls it's one screw straight on top extending down through it.
Edit
Just checked 4412 diagram, they are the same.

 

Maybe we are talking apples and oranges LOL. I was referring to the phillips screw that holds in the squirter.

 

Ah, the single screw on top of the carb? Got it.

 

Here's a parts diagram link if you need it.

http://documents.holley.com/techlibr...loded_view.pdf

 

Ran OK no ping at steady cruise though noticeably less power when passing, interesting just a couple degrees of timing makes a big difference. Dialed back in a little more advance. Should be close to 12 BTDC. The cruise ping also may be years worth of carbon in cylinders lighting off, too. Making progress though.

 

Did you try it without the vacuum advance yet? You need to focus on mechanical first, then vacuum.
Another thing to realize is when you back off on the initial timing is you change the total timing. If you are reasonably sure that the total is good for your combo, then you need to also increase the amount of mechanical advance.
I think you said you have the Motorcraft distributor. If you spend a day at a good junk yard, you should be able to come up with a selection of points cams/advance plates which can be used as is or modified to get the amount mechanical advance you need for the initial advance you run. It's time consuming, but worthwhile once you get it worked out, and pretty cheap.

 

The "total timing" is 36 to 38 BTDC (vac disconnected) by 3000 RPM, but will check again to be sure. The sweet spot for initial or crank timing seems to be around 12 deg. While I haven't actually dug into the distributor itself, by measurement the spring and slot combination can be deduced as about perfect.

 

Hey Ted is there a warmer than stock cam in your engine?

 

I don't believe so, I dunno though. When the engine was being rebuilt the guy asked about that, I figured a stock cam would be OK. He didn't seem to agree.

 

Hmm
Could be the reason it likes a little more timing.
Maybe your builder slipped an "rv" type grind in there.

 

Could be. Thanks to FTE it runs a lot better than ever before. Took me forever to get all the "pieces" to come together, either lack of the time, or money, or knowledge; etc. Y blocks respond pretty well to more advance than stock settings from what I've read. The distributor advance curve is not very good though and has to be changed for this to work, like most engines.

 

Yup, agree they respond to timing.
I always figured that normal was about from 8 to 12 initial, depending on the engine.
What I'm curious about is how/why it ends up handling a carb that's a little to big.
Sounds like you're sneaking up on the tune though.
Nice

 

If you have 20inhg at idle, then it is a stock cam, or pretty close.

If you haven't dug into the distributor, then it's not very likely that you have 36-38 degrees by 3000rpm. It's probably still advancing past 3000rpm; you want it to stop advancing at about 3000rpm.

Have you actually swapped advance springs and looked at the slot which is engaged on the advance mechanism?

 

Great points Charlie

 

Might not be very likely, but it is what it is. As you might imagine, I was pretty stoked because it saves a lot of hassle.

It's simply a matter of running it up with a timing light and see where the advance ends up. We can determine the spring and slot combination installed, without actually tearing into it, by noting when (RPM) and where (BTDC) the timing ends up.