Switching out distributors on my 440

[DocMel]

Im changing out my distributor (no vacum advance) for one that does

I havent switched out a distributor in a long time:   Basically, Im assuming if my current distributor rotor happens be pointing to the #6 spark plug post before I remove the distributor,  if I just install the new one so the rotor is pointing to the #6 spark plug post once its seated and installed, Im in the ball park, correct?

[AMXguy]

Yes, I'm not sure about small blocks but big blocks can only go two ways, the right way and 180 degrees off so it should be obvious.


 Unless you're running a smogger set up be sure hook your vacuum up to manifold vacuum, not ported. this idea may get some disagreement but  it's the way these cars were designed to run. I can steer you to a good read on why if you're unsure.

[Chryco Psycho]

you are right , there is only two positions the dist can go in but rotating the body of the dist sets the timing
 I totally disagree on the vacuum advance , connect it to ported vacuum unless you enjoy over heating as the timing retards with added RPM

[Strawdawg]

If the new distributor is phased exactly the same as the original, then it should just pop straight in.  I always mark the old rotor position on the distributor body so I can try to approximate the initial setting as closely as possible for the first start.

I mention the phasing because I bought a new distributor last fall and it was not phased the same as the original and when I dropped it into the oil pump drive, it was two or three cylinders off.

[AMXguy]

This is always a debate no matter what make of car you're talking about,  chryco since manifold vacuum is the result of the throttle  not the rpm I'm not sure why you say it retards your advance with engine speed ?  under wot you do loose that vacuum and therefore your vac advance but thats what you want if you set up your advance curve accordingly. maybe on highly modified or race engines I can see it but I'm talking pretty much stock street engines. I fought with my 440 for a year until I sent my distributor to FBO and had it curved, when Don told me to hook it up to manifold I argued with him but gave in and tried it. it worked so well I went and switched all my cars back to manifold and never looked back.


 The best read I've found on this is " Timing and vacuum advance 101 " by John Hinckley. I don't know how to post it here but if you google it you can find it all over. I guess I can't say with 100% certainty he's right but if anyone can prove him wrong I haven't heard it so far.

[Chryco Psycho]

again I disagree manifold vacuum is highest at idle advancing the timing & drops to virtually zero at WOT retarding the timing at wot this essentially works opposite to the mechanical advance insid ethe dist so u have the dist advacing with rpm & the vacuum retarding with more RPM , the ported vacuum is opposite so you timing becomes virtually no curve , the ported vacuum goes the other way with no advance at idle & increased advance & at WOT you will have the most advance , in the past I have limited the max adavnce by inserting an allen wrench into the vacuum advance pot & DIALing out max advance , in my world this keep the car form over heating , typically on higher HP engines i never connect the vacuum anyway to allow more initial timing without over advancing the timing , if it works for you great but I have always had problems with vacuum advance connected to manifold vacuum

[AMXguy]

What you're saying goes right along with what some of the best engine builders I know say, but then the other half totally disagree. this is why the subjust interest , how can you have such strong opinions on both sides of a pretty simple basic decision of where to hook your vacuum source? I can't think of another mechanical issue thats so simple yet has no concensus.

 I don't claim to be an expert but manifold vacuum makes perfect sense to me, start out with 14 or so initial, set your machanical to be all in around in a 2800 or so then let your vacuum advance bring you up to 50-55 at cruise speed, when you open the throttle it drops the manifold vacuum off protecting the engine yet gives it advance when it can handle it. I have had to limit the vacuum advance in almost every case, but so far it's worked great on every street engine I've tried it on and after all in most cases that's where the factory put it. maybe this debate will go on until our old cars are all off the road , I sure don't think it's going to be resolved soon.

[73EStroker]

You should change the distributor with the engine set to fire #1 TDC. That way - phasing of the ditributor is not a problem. You simply set #1 plug to where the rotor is pointing then plug in the leads -8-4-3-6-5-7-2

[Kevin71]

I have been having ignition problems ever since I got the car back from the painter.  They pulled the engine to paint the bay.  First one wire was off and it was vibrating very bad as you reved it up.  Put the plug wire back on and was still running bad.  So I repalced the plug wires and found one that was shorting against the header.  Runs much better but still doesn't seem to run quite right.  So I have been trying to find a new cap and rotor but don't know the make or model of the dist.  It was in it when I bought it.  It's a electronic one.  After trying several caps I have finally come to the conclusion that it is most likely a Profrom which would be the cheapest and since the seller in retro spec was very cheap.  This must be it.  Jegs says they will have to call Proform for a part number.  Anyway is this thing any good.  The car has never seemed to perform to it's potential.  It won't rev past 5000 rpm.  Also how do you set your advance on the vacum.  How much advance do you need and at what rpm.  Is more better at some rpm's?