is there a variable digital MSD box so you can run extream compression and the timing will adjust @ idle= no ping.
I notice they have built in rev limiter .

this is all conjecture. I have that cast crank 1980's truck engine and thinking radical experiment...

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The proper compression ratio with full timing makes more power than a higher compression ratio with retarded timing all else being equal. I suggest you find a copy of David Vizard's book Performance With Economy and read it from cover to cover.

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Joshua

OK
but I thinking variable timing...

uknow it strange but Mary's new bought 2006 outback 189Kmiles gets 29mpg HWY according to the onboard computer. it has variable timing, the mpggov web site states it should get 26 mpg NEW.

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Did you notice it is for "single cylinder".

Richard

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Part of Tyrde-Browne Racing

One item that will bollox this, is the engine design itself...even if you whack .125 off the deck, and .125 off the head and with stock pistons, end up at 13:1 compression, the intake valve timing event will limit the build because of the clearance between the piston and the opening intake valve chasing it...

This is where things get touchy and welding up the chamber or a set of dome/valve relieved pistons would help get there without the intake valve contacting the piston...this is why the turbo guys get the field because they don't need to get that close, but can pack the cylinder to get the power out of it.

But that being said, a cast crank engine in the 11-12:1 range would rev up fast and shove a 60's car pretty hard down the range with the right combination of gearing and intake with headers...

I had done this to my last forged crank engine, with the deck height being pretty low, and my chamber being about 36cc...the calcs put it at 13.1:1 SCR...once I mocked the engine up and degreed the cam the valves all marked the pistons...so I had to pull them and 'notch them'...the notches were deep enough (about 6-7cc per cylinder to have good clearance when hot between the piston and valve-I did it at a tight .187 at the peak of the notch which got me a .020 margin of whoops), that it knocked my SCR back down to 11.67:1.... I just took this engine out and the burn pattern on the pistons looked even and no contact with the valves even hot during a 6000 rpm launch. (Too bad the clutch didn't like it...)

Make sure to take the time to brush up on your geometry skills as there is a bit of head scratching and some number crunching when you get to this point even if you break out the clay and check everything...

Back to the original idea, I think if I were to build an 'unlimited' slant, I would opt for the MSD programmable that would adjust the timing per cylinder to get the best burn out of each bore coupled with EFI and Computerized timing curve. (Luckily SS racing doesn't have rules against the MSD-7 and up boxes luckily, but you may not be able to use your car in other classes if so equipped.)

-D.Idiot

wrong ebay list fixed link.

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Ryan runs a fully programable MSD box on his Dart.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

has anyone run larger exhaust valves then intake on a carb engine..in a hi comp motor with overlap cam the large exhaust should in my thought let hot comp exhaust gas leave earlier, thus u could run a higher comp...?

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do you know his comp?

http://www.ebay.com/itm/MSD-7531-Progra ... ca&vxp=mtr

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why not just cut the head drastically ..why touch the block deck?

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The general rule on NA engines is to have the Exhaust valve about 3/4 the size of the intake as it is easier to empty the cylinder (piston pushing it out, and scavenging during the overlap event) than it is to fill it . If you run a larger exhaust valve you might increase the scavenging event, but during the long overlap event on a high duration cam, you can actually 'suck' the incoming air/fuel charge out the cylinder and into your tailpipe without using it (increasing your fuel usage, and if you get hot gases or a backfire, you might frag the exhaust pipes if loaded up).

Some people do run a standard dual pattern cam which is heavy on the exhaust event to help the headers scavenge better. (Instead of the RPD cams we normally get to keep the intake open a little longer to hopefully fill the cylinder better...).

Although I have not read the book Josh Recommended, I have David Vizard's other two books "How to build Horsepower Vol 1 and 2", I highly recommend them as a loose guideline in working up engine builds in general, he has a lot of good information in them (although the synthetic oil vs. standard oil section is a little dated...).

2 cents...

-D.Idiot

looks like headers would stop the reverse flow of gases..
http://www.mazda.com/mazdaspirit/skyact ... tiv-g.html

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I have run 11 to 1, 12 to 1 and 13.5 to one. same head same cam same intake,pistons ect... the car ran the same every time. MSD 7 al2 .. You do not need to beat up your engine with a lot of compression. It did however get faster with efi.
Will

r u gona try this
MSD 7531 Programmable Digital 7 Plus Ignition Control

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