Distributor setups for L78 or L72 engines?

[Salvatore]

"A good points system can work just as well".....We agree on something! WOW. I totally agree on a good distributor set up with a set of points.

[mbxlesney]

On my L78 Nova Iam going with a restored stock 1112000 distributor with a Crane pointless ignition with the built in rev limiter. so I can retain the stock appearance and not having the hassles of points. The GM HEI units in the mid 70s are great units but seem to remember a firewall clearance issues on 1969 Camaros and same period Novas.

[Keith Tedford]

I run points on our L78 with the same curve as Rob, all in by 3000 and idle it at 900 rpm. I ran the 427 the same way. I run a stock 429 B-R coil. The HEI died a couple of years after we bought the car and I had a 1111498 distributor on the shelf so that was used. You will be hard pressed to notice whether the last number is an 8 or a 9 with the unit installed. The car starts fine and will turn any rpm that I wish to run. I used to run the Delco D112P HD points in the old days. No problems to 6500. Now I run the Accel HD points, not the race units, and have no problems. So I change the points every 4 years. That's part of the fun of owning these cars. I've run the stock 4346 carb with #73 primary jets and #76 in the rear. Power valves front and back. Fine tuning on a chassis dyno might find some gains, but this is a pretty good ball park to start with.
If your HEI is in good condition, just ad the GM 990 module. Apparently the early modules had their problems. New modules are as close as your nearest GM dealer.

[Chevy454]

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On my L78 Nova Iam going with a restored stock 1112000 distributor with a Crane pointless ignition with the built in rev limiter.

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Not to discrourage you, but I heard in Stanton this year of some folks having some problems with the Crane unit...I'm not sure if Casey Marks tried one of the Crane units or not, but I do know he found that a set of points whooped the snot out of the Pertronix on the dyno...

[VintageMusclecar]

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...I'm not sure if Casey Marks tried one of the Crane units or not, but I do know he found that a set of points whooped the snot out of the Pertronix on the dyno...

[/ QUOTE ]

Rob;

That's the 3rd or 4th time I've heard someone say that (re: Pertronix). Can you give some details?

Eric

[Jeff H]

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I'm not a fan of the GM hei pieces...while they will work, *IMO* they look out of place, and believe it or not a good points system can work just as well. Anyway, when is your total timing in? And what compression & pistons you running?

[/ QUOTE ]

Rob, the motor is a bit of a mystery to me since it was built by a previous owner. All I know is it has the 820 oval port heads which probably lower the compression a little, the stock L78 intake, Holley 750(that's been messed with), the GM HEI distributor and headers. As for cam and pistons, I have no idea but will assume they are stock. I don't plan on racing the car and I'm not worried about 100% stock appearance at this point in time. Regarding the vacuum advance, I'm reading around 36 of timing with the vacuum adv disconnected. When I reconnect it the total timing jumps up to around 50 or so. Is that correct? Should the vacuum advance still be adding in at higher revs? I don't get any pinging so it sounds fine.

[@wot]

The vacuum advance unit is non adjustable an adds 15 degrees to the mechanical advance on a stock L78, yielding 51 total timing. If you are positive there is no detonation, check the plugs to confirm, leave it alone. If it is high speed detonation, back off the timing a couple of degrees. If you detonate under load, its probably the too much vacuum advance. There is NO vacuum advance at full throttle, engine vacuum will be close to zero.

[Chevy454]

@wot nailed...vacuum advance is for part throttle...36 is where you'll be under full throttle [ie: racing]. The general rule of thumb is to back it off till you don't get detonation and it will start when hot...that's for a street car, as your trap speed on your ET slip may actually tell you something different...

Eric: I had lots, and lots of troubles out of my Pertronix units, and ended up ditching them...I'll try and rattle Casey's cage and get him to chime in.

[Keith Tedford]

The Crane adjustable vacuum cannister can take care of over advance at cruise speed. Start with 10 degrees and work up.

[Salvatore]

Keith, I totally agree with your previous post. The points in my Z are from November 2000. (ACCEL) My stock distributor was curved to have everything in at 3000 rpm's. No problem to 6,500 and no pinging or overheating. Would not say my car is wickedly fast just seems to run fairly efficient. I tend to run it a little on the richer side with the Podell additive. Don't know if it is doing anything (additive) but I am not fixing something that is not broke at this point. I use the R44S AC Delco plugs.