Carb or ignition ?

[mbaird]

If it came across like I was suggesting that, I'm sorry.
Bold added to the crux of what may be the issue.


RPM drop of 30 is good. A/J may have a better sense of this cam than I do.
We're both suggesting more throttle and that may mean less initial timing. I was thinking 16 but maybe its going to be strongest at 14* 750 rpm.
Open the throttle, see what happens with respect to rpm.
Then take a few degrees out of the timing or whatever it takes to get back to 750 rpm. Fiddle with the mix screws - should need more open.
Test it shifting into Drive.
Also whether its burning your eyes.
Then see what the AFR meter says just for the record.

I had to drive out to a small town this week so I took my jetting kit and tried various rods & springs /idle settings & timing etc...

 

[AJ/FormS]

Experimented with initial timing and curves.

BTW
In my 367, the Hughes cam (223/230/110) would idle down to 500rpm ,in gear (manual trans), and pull itself on a flat, level, hard surface. Not a lot of extra power to climb mind you.
It did this with a proper T-slot sync, nearly 11/1 Scr, alloy heads, and just 5* of Idle Advance, and a stinking 750DP on the AirGap.
What I mean to say is this
just because one guy idles his 3000 stall hotrod on 25*, doesn't mean YOU should. Let the engine tell you what the LEAST amount of Idle-timing it will put up with, because we already know it wants , or is willing to PUT UP with high 20s . But like a contrary wife, you can't always give her what she wants.
BTW-2
If you have a 4-corner idle carb, the 221cam in your 360 does neither need nor want it, so I would figure out how to shut it off.

Do I need to drill the primary plate ?

I didn't "need to" , idling at 750/Neutral/14* initial.
But down at 550 in-gear it preferred to have a little, I'll guess because the PCV might have quit being the principal Idle-Air bypass .
So I compromised, and gave her a lil Idle-Air bypass, and reset the neutral idle speed to 700
The thing of it is, My Hughes cam had an advertised of
270/276/110,@.008 tappet rise, so that's not very big, very little bigger than the 340cam, so it idled VERY tame.
How does that compare to your 221/229/112 roller? I'm betting yours is more like 276/284/112, possibly at .006tappet, so that should be lumpy at 650 in gear. The 112LSA will play havoc with your AFR down there, so IMO, forget about the AFR at idle, as already mentioned.

 

[mbaird]

Here are the specs on my cam .

 

[AJ/FormS]

missed it by 2 and 2,lol

your other numbers; int/comp/power/exhaust, are;
274/115/ 97/282/54 o-lap,50Effective/ Ica of 65* @108 installed
270/115/112/276/53 o-lap,50Effective/ Ica of 65* @107; My 223
276/115/104/286/61 o-lap,60Effective/ Ica of 65* @110;My 230
@.050, the numbers are;
221/229/112 yours
223/230/110 my first Hughes
230/237/110 my second Hughes

The numbers in blue tell a little about fuel economy; the bigger the better.
The Effective overlap tells a little about the shape of the powerpeak; Smaller numbers point to a broad flat curve. Bigger numbers point to a more narrow,peakier bulge.
All of these have a fairly to very mild lope at 750rpm, altho yours will have a lotta energy still in the exhaust, shown by the rather small 97* of extraction. Whereas the 270Cam with 112* of extraction, made super hiway mileage.

 

[mbaird]

So how does this relate to my AFR dilemma ? Is it just how that cam is ? Wil my fuel economy always suck ? Lol