Hi, everyone! I picked up my new (to me) 1969 427/390 a week ago. Looking inside the distributor, I see a ring that seems to block access to the points for their inspection or removal. I haven't worked on a V8 for several years, and I don't recall seeing this part before. I'm sure one of you will be more knowledgeable. Is it some kind of shield that's simply removed for access by those screws I see? I've attached a photo with an arrow pointing to it. Thanks in advance for any advice!

 

Welcome trhs to the forums. Have not seen that type of ignition in awhile, that is one of GM's first high performance transistor ignitions, used on high performance cars. From 1966 to early 70's before they came out with the newer style hei type distributors. Most of the gm cars had point distributors, yours was considered high performance, you won't find a set of points in there just the coil pole piece. like the hei's this old style was larger than the hei's, Thanks for using a picture that helps your explanation a lot. I installed one of those units in the early 70's from a corvette not sure which one,on my 70 350 roadster worked great, I will post pictures that might help, a very simple unit, I can't say exactly where the transistor amp unit is mounted, up by the radiator left side maybe for cooling reasons, should be easy to see.

 

Looking around I see you can find all the parts needed to rebuild or repair that system, that's nice but they are slightly pricey. If you found a 69 in good condition that's a really good find, it appears the distributor looks untouched, that's good. Brother had a 427 L88 in a 68 roadster fun car on the street. I found more pictures. Lots of C-3 owners and fans on this site, always open for questions.

 

Thanks for the warm greetings, Thomas! I look forward to being part of this group. My distributor cap has the little metal sliding panel which made me think there was a set of points buried in there somewhere. I'll look for that transistor unit next time I'm under the hood. My main project is to get this car to quit stumbling at high RPM's; I'm not able to take full advantage of the power. It feels like an ignition issue to me, but I'm no pro. Previous owner mentioned something about the plug wires that he was able to solve by moving things around, but it's back and the weather is too cold for me to spend much time under the hood!!

 

I believe in the late 60's they used the same distributor cap for all V8's points or not. Stumbling could be many things, wires, plugs, fuel pump or filter carburetor jets, power valve, dirt, dirty sock in the fuel tank, bad gas. Not sure how many miles on your engine, cam going flat could be a possibility, crank it over with the valve covers off and check the valve rocker travel. The ignition coil may be weak, it looks like a new distributor tie down, replaced for some reason. The distributor looks stock, strong springs on the mechanical weights means it reaches full advance around 45 to 55k rpm, i'm guessing. Some people like full advance around 28 to 3k rpm, its more responsive, go with 15 degrees on initial timing (no vaccum advance) at idle and 20 degrees at 3k works good on most engines, 35 degrees total. or somewhere in that range. Everything dialed in it should run good.

 

Welcome to the forum. The C2s with transistor ignitions had the amplifier module on the driver's side next to the radiator.

 

As Thomas77 said , it can be many things. When it comes to timing you can do ONE of two ways, set your total advance, usually between 2500-3000, or set static, ( go with stock published numbers).
more than likely you have a fuel delivery issue at higher rpm. A good carburetor cleaning/ rebuild may be in order. Also check the fuel pressure.
Depending on the mileage on your engine you may need to check the slack in the timing chain. Not hard to do, let me know if you need the trick.

 

I appreciate the helpful ideas. I may have to wait on some of this since the temperature got cold right after I got the car! I will report back when I have a chance to investigate a little more. Maybe we'll get an unseasonably warm weekend! Thanks!!

 

Hopefully it's something simple like a fuel filter. You take good pictures and try to send more, keep us up to date on your progress. There is nothing like the rumble of a BB.

 

You're going to be disappointed if you live in the Midwest because it's supposed to be very cold this weekend.

In this era, GM used an aluminum gear with nylon coating on the teeth for the can timing gear. Not sure if the big blocks did this but I know my '68 GTO and '73 L-82 small block both had nylon coated gears. Replace both of them with cast iron gears. Also replaced the lower gear on the '73 with a cast iron gear because the factory gear was powdered metal and it decided to disintegrate about 1 month out of warranty. Fortunately the only damage was one exhaust valve got bent. Also during the teardown I discovered that the top ring on that piston was broken and appeared to have been that way since assembly.

Bottom line is that the nylon gears although a lot quieter (which doesn't make a lot of sense on GTOs & Corvettes anyway) wear faster and that will affect your timing as previously suggested by 74HARLEY.