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I need some schooling... What's the difference between the swing arms and the irs and which vehicles have which?

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Google image search "swing axle vs. irs"

69 and up US bound Beetle Ghia have IRS prior has swing axle with a few exceptions.
This info is all over the interweb.

Ah, so it's safe to assume my 73 Ghia is IRS. I want to use the stronger type 2 axels in my build.

It's pretty safe. are there axle boots at each end of the axle?
If so it's most likely IRS.
Next what engine and power expectations. You can do a lot on stock type 1 CV's

Bonemaro , what kind of driving are you planning on doing? Two joint (swing) IRS is good in some situation, four joint IRS is good in other situations and there are areas that either style will work just as well as the other.

Lee

My intentions are street performance, maybe the occasional autocross, but nothing to serious. Engine in the 150-160hp range.

I suppose you could make a case for type 2 CVs but I think I'd run what I had first and see where the true weakeast link was.

There is a guy on thesamba with a turbo Subie engine and he's breaking axles, not cv's.

If you go to larger CVs you also have some other things to change like drive flanges and stub axles. After all that you might as well coff up the Moo-la for some good half-shafts/drive axles.

http://www.blindchickenracing.com/How_t ... nd_cvs.htm

Lee

My son has all Thing components on his Baja (final drive flanges, stub axles, driveshafts and CVs) which were chosen more for increased angularity than for strength. In my own street bug I have the Thing flanges and axles but used Bus CVs - in order to use them on Beetle driveshafts the inner races have to be ground thinner (see the dimensions at the blindchicken site that Lee linked to). Definitely overkill for the engine I have now, but we wanted to step up the strength in case I ever put in a "big" one (and beefed transaxle).
Back in my circletracking days we ran nothing but Type I CVs and I don't recall anyone ever breaking one other than as a result of chariot-racing or slapping the wall - that was with 10" wide slicks and a locked differential under severe racing conditions.
You're probably better off NOT using stronger CVs if your transaxle has stock internals - it'd be better to break a CV than a differential or 1st gear.

BTW, the final drive flanges which fit a Type I trans but accept the 100mm O.D. CVs are found only on Things (aftermarket repos are available, as are welded-up ones made by joining a Bus flange bolt ring to a Beetle center)....but the CVs, driveshafts, and stub axles are common to the 924 and 944 Porsche. I would NOT trust a Chinese stub axle, besides the fact that most of them take larger bolts and the CVs have to be drilled out to use them the metallurgy is questionable.

I don't intend to use too much "stock" in the engine and trans. I really want this car to be quite exceptional when I'm done with it. I certainly wont be cutting any corners. Been waiting 13 years to start this project.

While we are talking about the dirty end of a VW, you will need an anti-hop/truss/kaffer bar setup to control the flexible transaxle/engine mounts and keep them in alignment with the rest of the car. This is a common need with broken/curvy circle racing (road racing, autocross, etc.) oval circle racing, drag racing or off-road or just farting/rat racing (as it used to be called) around for fun. They range from a two-piece kaffer bar to another lighter weight truss bar to an expensive but looking good "stiffy" bar. One of the STF'ers even has a design for a set of "monkey cage" style of support that looks pretty strong. It is a widely known thing that if your going to play games you gotta protect your A$$!

Lee