I ran a mag on my 39 but there is no curve I didn't like the idle too much just didn't match what I was doing the GMC has a mild cam and not much compression

Mags are fine Expensive but fine......

Pushin' half the track.....BS

Listen up I took the mag off the GMC and put it on the 39 BMW
BMW had a real cam in it.... it would idle at 500 rpm start on the starter and run 6000+

If you wanna play get a Vertex and go see Hunt Magnietos
A rebuild will cost you a couple hundred
Vertex use an impalse spark and have a plate that dictates the curve

Hot Rod...You speak as if you have never had your hands on a mag! If you don't think a mag puts out a real spark at no RPM just pick up a Vertex and turn it by hand holding the end of any or all plug wires but do it over a bench please Cause when you drop it you don't wanna break the cap!!!They cost a ton

Tony they don't break starters unless they have the wrong advance plate

GMCKUSTOM

I'm build the engine your talking about....but please know the 12port is also a myth in some ways....but it really looks GOOD

I'm sorry this isn't flaming and I don't mean any offence but some of you are wrong
I have had my hands on all of this and run it! I'm not guessing

The old school drive is an SW and you get a mechanical tach drive with it

If you look at the photos of the 39 here I think you can see it

The dist or mag used with this is a blade like a VW

The drives are rare but out there

I don't think Vertex or whatever they call themselfs today make a six

Do a Google for Hunt Magnitos they are just the best...nice guys that know their stuff