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Set up for MSD 8524 distributor--- 264ci nailhead

Guest btate

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Guest btate

Does anyone know which color spring and which color bushings I need to use for a 264ci nailhead? The msd 8524 kit comes with these extra parts in order to set up for other engines apparently.

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Find a place to mark off a quarter mile. Then check initial timing, plugs, etc. Get a stop watch and try each combination until you turn the fastest time. That dials it in to your engine.

Did you just say a word you can't use on the radio?


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Guest NikeAjax

I opted for this one:


Looks ugly, but geepers, it works great! What's nice about the MSD is that you can run super-cheap gas, sometimes I joke that you can use cat-urine, but the truly best part is it's "fire and forget", meaning when it's done right, ya ain't never gotta touch it again!!!!


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The different springs are to allow for faster or slower mechanical advance curves . . . for ANY engine, not just Chevies or Buicks. Very possibly more generic in nature, the springs and bushings, than model/engine specific, I suspect.

Generally, mechanical advance needs to start about 1000-1500rpm. With the engine not loaded, as in "in Park and the parking brake set FULLY", take the rpm up to about 2500rpm and see where the TOTAL of the initial timing, vacuum advance, and mechanical advance might be . . . it helps if you have one of the timing lights with the dial on the end, to do this. With the initial timing set "to specs", many cars from the later '60s and earlier '70s would have a total advance number of about 45-50 degrees BTDC. Remember . . . when you throttle into the engine, under load, the vacuum advance decreases and it's the mechanical advance that "carries the day" under those conditions. It's this WOT advance which eveyrbody usually worries about when they quote "total advance" (initial + total mechanical) figures, NOT the figures I mentioned for what would be "part throttle cruise". It's also the vacuum advance + mechanical advance at "cruise" conditions which greatly contributes to highway fuel economy.

I should also mention that the supplied springs are designed to work with the "supplied distributor weights". Sometimes, it's necessary to "tame" some top-rpm advance by mixing a lighter spring with a heavier spring, yet still having the quicker advance at lower rpms. Many of the heavier springs also have a "loop" on the end to allow the lighter springs to "work", yet be limited somewhat by the heavier spring at higher rpms. In other words, one distributor weight flies out first, to be followed by the other one as engine rpm increases a certain amount.

The springs are there to modulate how quickly the timing will advance, mechanically, and the bushings are there to limit total advance attainaable.

Once you get the engine running at the basic factory timing spec, with possibly the middle spring set, then do the timing advance checks and see where things might be. Then take it for a drive. Check for off-idle response in normal driving. then go up to about 45mph and see if it's got any "ping" with light throttle application, then medium throttle application. If that all checks out, then go deeper and see about heavy-throttle ping (or worse). I'm not sure what the optimum timing specs are for the nailhead engine family members, but it's possibly somewhere between 32-38 degrees BTDC at about 4500rpm, or thereabouts. It might be easier to find the recommendations for the later 425s and 401s than for the earlier version you have. For general principles, not knowing what the particular recommendations might be, I think I'd aim for closer to 35 degrees BTDC total mechanican+initial advance, maybe event closer to 32 degrees BTDC, considering fuels of today . . . but also knowing the poor reputation "West Coast Regular" gasoline had for being a little lower in octane than similar regular fuel in other parts of the (lower altitudes) USA, in the 1960s and prior.

I suspect that IF you could get a combination which would run on "mid-grade" fuels, and do it quietly and acceptably, that would be good. Or even on normal regular, would be better.

The suggestion of doing "timed runs" is an old hot rodder orientation for tuning an engine for best performance. NOTHING wrong with that! IF you can find a place to do that anymore. Sometimes, freeway on-ramps can work, if they are long enough to try various rates of acceleration and still merge easily with traffic (IF there is any traffic). Personally, I like to notice how the car feels and responds to throttle input. Even if you have "lower power", IF it's responsive in nature . . . rather than acting like "You want to do WHAT???", that responsiveness and willingness is (to me) more important than time-to-speed/distance numbers. This is why my main focuses are generally on lower speed.off-idle and mid-range throttle input areas, but what happens at WOT is still important, should the need ever arise.

Back when many car companies were headed toward OHC engines in the 1980s, one magazine guy asked a Buick operative why THEY were not doing something similar to the ground-breaking (at that time) Olds Quad4 engine. The Buick operatives was something like "For our customers, acceleration stops when they get across the intersection." Which, many times, translates into "lower-rpm torque", rather than high-rpm horsepower ratings. What happens at 5000rpm is not important in getting across an intersection, from a dead stop. Lower-rpm and mid-range rpm torque is what "makes things happen" for most drivers in normal situations.

With a smaller displacement engine, you need that lower-rpm torque to get things moving, responsively. And, without having to get too deep into the throttle, you can also keep the carburetor out of the "power mixture enrichment" phase, which can mean "more power, less throttle, less fuel consumption" . . . hopefully.



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