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I've got plenty of them and the last time I looked, was at a 7AL3 15 years ago don't recall any issues. I would figure the offset would be constant at such a low frequency range. 48,000 degrees a second seems like a red herring as your your firing event period is about 1msec. FYI, 1 degree would be 10µsec offset at 8K rpm (1/90 of the spark to spark period)

I would have expected the manufacturer's stuff to be more stable. Thank goodness its repeatable, but I would hate using a timing light at 8K rpm.
I don't see it as an "issue", It just is what it is. Electronics have slew rate, and like you say, it is stable and repeatable.

As we see in car forums all over the internet, the old school MSD 6AL and 7AL and old OEM HEI modules retard about 1 degree per 1000 RPM. Some Chinese HEI modules are crazy slow, 2+ deg per 1000, and the slew rate seems voltage sensitive, just nuts, crazy junk. This slew rate retard deal has been mindfucked to death and just is what it is. Physics.

I guess you are saying you have plenty of scopes? or ignitions? Ponder this some more and look again, or just do the math and eventually you will have the epiphany. If you say "red herring" because you doubt 48,000 deg per sec. just do the math. I don't doubt you can understand it if you wrap your head around it. It really doesn't matter because we can't change it. However, we can make advance mechanisms compensate for it.

Now that microprocessor controlled timing with programmable tables is becoming more available, it will all be a moot point before I run out of distributor machines. I just bought another yesterday, a fixer-upper. It gives me pause to think distributor machines are older than most of the people reading this.
 

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Good stuff ^^ but not it.
Good stuff ^^ this is it.
Oh yeah /\/\ there it is. Thank you Thank you ....

You see why I thought it must have been a misprint and that they mixed crank and distributor RPM? Look at the curve for automatic, 2000 to 3000 is 4000 to 6000 crank RPM and 8 to 13 dist. is 10 degrees crank advance from 4000 to 6000, which just seems nuts to the "all in by 2500" crowd.

Understand that I finally understood it wasn't a misprint about 25-30 years ago when I got into tuning carb restricted circle track engines and realized how much more timing was necessary and a significant advantage when VE is limited.

When you consider how the overall 428 SCJ engine was configured for Super Stock (at that time ~1968) with the small carb (735 CFM) and not so stellar breathing, with the 330 deg .600 lift cam which is going to want to turn high RPM where the VE is falling because of the small carb and meh heads, it makes sense to add that much timing because the cylinder pressure is falling significantly as RPM climbs. It must have worked OK because the Ford house cars (Tasca Ford and I forget who else) were on top of the game in their classes.

Notice in the other sections of the publication about the 427 with Tunnel Port heads and higher compression ratio, same 330 deg .600 lift cam, the recommended curve is not like the the 428 SCJ, the 427 is "all in" at 4000.
 

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At that compression range, 9.5:1 - 10.5:1, 1 pt would be worth 5% Max. ...probably closer to 4%.

A 500 hp engine might see 25hp from the compression bump. If there's more than that it's in the head design, or flow not the compression.
In the test the 6.0 with cathedral ports made 525 hp and then 544 with the LS3/L92 head.

No doubt that 4-5% is the rule of thumb but I believe their is more going on than just the compression ratio. I think a 0.6 jump from 9.6 to 10.2 on a 6.0 w/ LS3/L92 heads is going to be about 4% or slightly more. The cathedral ports tested were 799 heads with 64 cc chambers that flow ~250 cfm, the LS3/L92 rectangle ports tested were 823 with 69-70cc chambers and flow ~315 cfm. If it were the 799 heads bumping from 9.6 to 10.2 I would expect it to be in the 2% increase range because the head flow is close to being maxed out already. However, LS3/L92 head isn't any where near maxed out on flow in the tested setup and with that 0.6 bump you would get 2% from the ratio and another 2% in increased head flow efficiency.

My 6.0 with LS3 heads and a 10.5 compression ratio makes similar power as the engine tested and I have a much much smaller cam.
 

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Great informative thread. Thank you Yeti for your wisdom and experience. Who would have thought we could have this kind of adult conversation in TOBT!
 

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All those long nights at the Holiday Inn got to be good for something, can't let them go to waste.
 

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Great informative thread. Thank you Yeti for your wisdom and experience. Who would have thought we could have this kind of adult conversation in TOBT!
Some phuckstick must have reached his allotment of Ford threads to phuck-up. :unsure:
 

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Every one of these Boss 302 "ports are too big" rants inspires me to repeat this.

The single thing that wakes up the Boss 302 is the advance curve Ford published in the off-road tuning literature, the "Muscle Parts" books. They specified the spring part numbers and fortunately they were the same springs as in '65 and '66 300 HP 390 engines,
Ford Performance Book #2 ( found the book today)









The first tip is: "The first step in going for more revs is to disconnect the limiter"
 

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I don't see it as an "issue", It just is what it is. Electronics have slew rate, and like you say, it is stable and repeatable.

As we see in car forums all over the internet, the old school MSD 6AL and 7AL and old OEM HEI modules retard about 1 degree per 1000 RPM. Some Chinese HEI modules are crazy slow, 2+ deg per 1000, and the slew rate seems voltage sensitive, just nuts, crazy junk. This slew rate retard deal has been mindfucked to death and just is what it is. Physics.

I guess you are saying you have plenty of scopes? or ignitions? Ponder this some more and look again, or just do the math and eventually you will have the epiphany. If you say "red herring" because you doubt 48,000 deg per sec. just do the math. I don't doubt you can understand it if you wrap your head around it. It really doesn't matter because we can't change it. However, we can make advance mechanisms compensate for it.

Now that microprocessor controlled timing with programmable tables is becoming more available, it will all be a moot point before I run out of distributor machines. I just bought another yesterday, a fixer-upper. It gives me pause to think distributor machines are older than most of the people reading this.
So Yeti let me get this straight with these ignitions if you have it all in by 2000rpm by the time you hit 7000 you lose 5*. ?
 

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My friend restores Mustangs and always dynos the motors and his last Boss 302 made 330HP through the stock exhaust. This motor was built to 100% stock 70 boss specs. He also did a 69 boss 429 and it made 440 hp. 428CJ made 377.
Good stuff ^^ but not it.
Good stuff ^^ this is it.

Oh yeah /\/\ there it is. Thank you Thank you ....

You see why I thought it must have been a misprint and that they mixed crank and distributor RPM? Look at the curve for automatic, 2000 to 3000 is 4000 to 6000 crank RPM and 8 to 13 dist. is 10 degrees crank advance from 4000 to 6000, which just seems nuts to the "all in by 2500" crowd.

Understand that I finally understood it wasn't a misprint about 25-30 years ago when I got into tuning carb restricted circle track engines and realized how much more timing was necessary and a significant advantage when VE is limited.

When you consider how the overall 428 SCJ engine was configured for Super Stock (at that time ~1968) with the small carb (735 CFM) and not so stellar breathing, with the 330 deg .600 lift cam which is going to want to turn high RPM where the VE is falling because of the small carb and meh heads, it makes sense to add that much timing because the cylinder pressure is falling significantly as RPM climbs. It must have worked OK because the Ford house cars (Tasca Ford and I forget who else) were on top of the game in their classes.

Notice in the other sections of the publication about the 427 with Tunnel Port heads and higher compression ratio, same 330 deg .600 lift cam, the recommended curve is not like the the 428 SCJ, the 427 is "all in" at 4000.
That 330 600 lift cam was meant for a 427 which is a short stroke big bore engine not a smaller bore bigger stroke like a 428 CJ . My buddy Barrie Poole raced super stock then and won the Winter Nats 2 years in a row 70 and 71 in a 69 Mustang coupe . He learned short shifting picked the car up over a tenth .He was shifting at 5800 rpm while the rest were shifting much higher . The Stark Hicky driver asked him to drive his car and he went a tenth and a half quicker than it had ever gone by short shifting .
 

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Ford Performance Book #2 ( found the book today)









The first tip is: "The first step in going for more revs is to disconnect the limiter"
Thank you. That's it, the curve for the Boss 302. Thanks again.

When I look at the detail in that instruction, 1 crank degree per 1000 RPM from 2000 to 8000, I figure it is significant that Ford specified each 1000 RPM from 2000 to 8000. But what would they know? The experts in the magazines (and the internet) say, "all in before 2500."

:)
 

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Ok thanks. So your saying ramp it in slowly so that it finishes its curve at or near peak hp.Makes sense. I never heard that before.We did notice the drop though but couldn’t understand why. Makes sense now. I’ve always done it the fast ramp way and it seemed to work good. Sorry if I sounded gruff I didn’t mean to be. Thanks again.
 

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Long Live The King
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Thank you. That's it, the curve for the Boss 302. Thanks again.

When I look at the detail in that instruction, 1 crank degree per 1000 RPM from 2000 to 8000, I figure it is significant that Ford specified each 1000 RPM from 2000 to 8000. But what would they know? The experts in the magazines (and the internet) say, "all in before 2500."

:)
More than likely Smokey taught them that ( Oh different thread)

Oh ... You are welcome for the info. I had to dig thru a few boxes.
 
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