Setting timing on a 225??

Yeah, I figured that out too, which is why I just snugged the bolt down just enough to make the initial setting, then pulled it back out for final tightening. Its just too frustrating to try and do it all down there, with bigarse hands.

Sarge
Power timing. This is very important.
Inside the dizzy is a mechanism that automatically advances the timing beyond what you initially set it to. This amount can be in the range of about 28 to 36 degrees, in oem units.It takes some 2400 rpm or more above idle,to achieve this full rpm. This timing has to be kept at a safe value so that your engine isnt damaged under full load/ full power timing, due to detonation. Detonation wreaks stuff. Important stuff like bearings and pistons. This safe full-power timing is usually around 36*. The factory units have this built in. But when the end user starts adding timing at idle, the same amount gets added to the other end. NOT good. So whatever you add at idle, you have to subtract at the top.
-The safest way to do this is to determine beforehand what your dizzy is doing. What I do is simply check the idle timing( at 0 to 10*BTDC), and then rev er up until it stops advancing, and record the numbers. Supposing your idle-timing is currently set a 5*BTDC, and it stops advancing at 35*. Doing the math means ; 35 - 5 = 30* in the dizzy. Thats about right for a stocker( 35* being less than the safe limit of 36*).
-Now you might want to increase the idle timing to 16*. Well 36 - 16 = 20* would be the new limit in the dizzy. You would have to modify the automatic advance mechanism to do this before you apply full-load/full-rpm to the engine, to prevent internal damage. At light-load/lower rpms the engine might happily accept the extra timing. And it seems there is a wide range of acceptable timings at those load settings. However, at full-load/full-rpm, there is no such variation. 36* is pretty much it, no matter what the engine combo. There is a bit of wiggle room in this number depending on the fuel used.
-Now the thing you really want to know is how to limit that automatic advancing feature, right? well 1st lets call that feature; centrifugal advance. Once you have the dizzy out, you will see there are 2 flyweights in there, that fly out with rising rpm and return with falling rpm. The amount of motion is governed by a slots and pins arrangement. The length of the slot determines the amount of travel. So all you have to do is limit the slot length and you are in business.
-So measure the slot length, and the pin od.Subtract the two and you are left with a number that represents the effective slot length and the advance that you previously measured by revving it up and idling and doing the math. I dont recall the pin size, so Im gonna guess at the following example. Say the slot is 4/10 of an inch; thats .400, and the pin is 5/32;thats .150. The math says; .400 - .150 = .250 is the effective slot length. And your centrifugal was 30*, as previously measured. again the math says; .250/30 = .008 inch per degree. Now you want to try 12* idle timing, and want to limit power-timing to 32* to allow up to 4 more degrees of initial idle timing to play with. So the math for that would be 32 - 12 = 20* centrifugal. and the effective slot math would be; 20* x .008 = .160 , now dont forget to add back the pin size (.150). So; 160 + .150 = .310, the new total slot length.
-So in this example you would have to shorten the slot from .400 to .310. This is usually done by welding. Or brazing.I like brazing cause its a bit easier to hand file. I also like to put a bit of extra material in there for two reasons. Firstly,its easier to file some more out than braze some back in and refile, and 2) It allows me to make a pin-matching cradle in the brass to prevent the pounding out of the brass over time.
-It sounds like a lot of work for very little gain, like you said. But it was really worth it on my slanty. The engine really woke up, and the torque/mpgs were really noticeable.
-Theres a bit more bad news. To gain access to those slots, the cam will have to come off the top. And thats often a battle with that stupid little spring that Chrysler put in there, to do the holding down. Its not bad getting it off, but back on is often a challenge. After I get it apart I drill and tap the top of the shaft for a tiny machine screw. Problem solved.Well not quite; You have to figure out a retaining system under that nice new screw. A bushing and properly sized washer and a lock washer for the screw did it for me.
-If this is a daily driver, it would be best to obtain a spare dizzy to be modded beforehand, as this modding can really chew up some hours.
-Looking back, this is one of those mods that Im really glad I did, despite all the work and hours. Your results may vary. All the best to you.