Trying to tune 64 riviera 425

I've had this car about 1 month now and I'm trying to get it to run smoother than it is. Some of my problem is broke, worn motor mounts which I hope to replace soon. My pass side exhaust manifold hits the crossmember, frame of car when in drive sitting at a light. I have new plugs, cap, rotor, pertronics ign. and wires.

Here's my problem. It seems that the carb may not have a ported vacuum line so the distributer vacuum adv. gets full manifold vacuum at all times.

Is this normal? Engine bearly runs (timing at 2 BTC degrees) without vacuum adv hooked up and when hooked up(timing can't be measured without timing tape) it seems to at to high of an idle.

Car runs great with no detonation at WOT. Just wanting to make sure things are set right.

What do you mean that the timing can't be measured without a timing tape? Don't you have a groove in your balancer and a timing pointer on your timing cover?

You have to set the timing to specs first(your Pertronix eliminates dwell worries) then you have to adjust your carb idle and mixture. It is normal for the idle speed to drastically change when you add or take away vacuum advance from the engine. It should run fine with full advance to the distributor at idle, you just need to get the base timing right with the vac advance disconnected then adjust the carb with the advance connected....piece of cake!

If your timing chain is worn you will NEVER get the timing right.

Arnulfo

On a 50 year old car, it wouldn't be unheard of for the timing ring to slip on the balancer. There are ways to find the TDC of the #1 cylinder w/o the timing ring. Find a YouTube video that shows you how then mark your timing ring. You might need to look for info on 'degreeing a camshaft.'

There are also ways to check for timing chain stretch w/o removing anything. You can do it by watching the rotor on the distributor while turning the crank bolt with a long extension. If the bolt moves but the rotor doesn't, a new chain - or new gears (nylon has worn off reducing the diameter of the gear.)

I just wanted clearification that the vacuum line for the vacuum advance has to get full manifold vacuum at all times. I thought most engines weren't supposed to get full vacuum running to the distributer at idle. Timing mark is steady with timing light at all rpm's so I'm assuming the chain is ok.

I just wanted clearification that the vacuum line for the vacuum advance has to get full manifold vacuum at all times. I thought most engines weren't supposed to get full vacuum running to the distributer at idle. Timing mark is steady with timing light at all rpm's so I'm assuming the chain is ok.

You`re OK

Tom Mooney

no ported vacuum source on my 65 either.

Manifold vacuum to the distributor was normal for pre-emission era engines. In the early 70s ported vacuum was then used to reduce hydrocarbon emissions at idle.

Thanks for the replys. I just wanted to be sure that it was hooked up right. There's a lot to know about these cars that is different than what I'm used to.