Well, I've got a 305 of indeterminate origin with a Holley 4-barrel to handle the fuelling needs. I haven't inspected the distributor yet because she's running ok. However, I've noticed that the cap has a metal flap covering an opening at the front of the cap. When you pull this up it reveals a screw, obviously to adjust something, but what I''ve no idea yet. Timing advance maybe?Without unclamping the dizzy?

Can anyone help?

Cheers,
Mark.

Mark,
Sounds like that DIZZY is REALLY OLD! That adjustment screw is for Mechanical Contact POINTS! Don't touch that screw until after you study a manual on adjusting POINTS!
Sincerely,
Kurt

I would promptly grab a 9/16 wrench and unbolt that thing and throw it as far as i could...

Go to a junkyard and grab a non cc HEI distributor or buy a new one they are fairly cheap.

Sincerely,
Kurt

Rover used those on the old Buick 3.5, it is indeed to adjust the dwell angle [points gap] while the engine was running, for super accurate settings.

Time to get a new one one and donate the old one to the Science Museum.

I got a brand new Mallory with coil and vacumn advance, off e-bay for £70.

WOW! (Wonders just how damn old my V8 is!!)

Will definitely be pulling the cap off now. Don't worry, not messing with the points! Until I get a dwell meter, and a cigarette packet to set the points gap (Apparently, old school mechanics trick - the *** packet cardboard is about the correct thickness, at least on some bikes!)
Instead of swapping out the entire distributor, can't you just get a breakerless electronic module bunged in there?

Thanks for the help Guys!

Mark.

the reman hei dizzy is pretty cheap don't waist your time with that old dog.

on the back of the engine where the tranny bolts up to it on the driver's side is a number stamped into the block.. if you have that number it can tell you what year range that block was produced.

You should be able to get the number fairly easily with a small flashlight then check out the number at www.mortec.com

Yes you can, I've got a Pertronix unit in my Vette.

OK, out with the flashlight tomorrow, check my engine no. and then sort out my options. I attempt quite a few automotive jobs, but swapping a distributor over isn't one of them yet!

Thanks again.

Mark.

One thing before you pull the dist...

Do you have a timing light? or can borrow one?

I don't have a timing light, but I think I can borrow one. Hell, I think I'd better buy one, especially if I get one which handles 4, 6 and 8 cyl engines.
I've been meaning to check how far out my tachometer is too. I think you can get lights with built in tachos.

Cheers for the concern

Mark.

Nothing wrong with a points style dizzy, if you're not RPM minded. If you keep an emery board fingernail file, screwdriver and extra condersor in the glove box...I can gauratee you'll never get stranded by a dizzy issue. IIRC the points are adjusted by a 1/8th or 9/64th allen head, I have a flexible shaft one, but don't recall the size.

HEI does offer some benefits, but a properly tuned point style ignition will serve a daily driver well if you keep it maintained.

Treat that engine with respect, It is probely older than you.
GM switched to the HEI in the mid to late 70's

It's a bastard, if it really is a 305. Chevy quit making points distributors before they started making the 305.

I had a Pertronix conversion on my '57. I heard but never confirmed problems with timing control at higher RPMs with them. I'm running a GM crate HEI with Crane HI-6 now.

a original classic car ok, yes keep it but, a car that it never came in? seems like a step backward to me.