So ... It's time to rehab the front end on my 69. Currently it's all stock minus a fast ratio box. I'm going to be installing hotchkis SBC 2in drop springs, global west off set crossshafts, del-a-lum upper and lower bushings and new ball joints. I've hemmed and hawed over this and feel pretty confident that I've nailed the right parts. Currently my alignment is at factory settings (I.e. Castor at 0 +\-). The car is numbers matching and I'm the second owner. There are a few mods here and there but no massive departures from stock. I've been reasearching the guldstrand mod (g-mod) (drilling my upper control arm perches) for awhile and while I see the value on paper I'm looking for someone who has done it and can say that it's worth drilling and grinding out the subframe and control arms on a numbers matching car. Or will adding the cross shafts bushings and doping the alignment (castor to +4 with shims) be just as good. Any advice will be greatly appreciated.

If you have reservations about drilling and grinding on your frame there are other options such as going with a SPC upper control arm and a tall ball joint from sc&c. This would give you the benefit of no spacers, all the caster you want and the camber numbers your looking for.

I did the guldstrand mod on my car. I didn't drive enough before hand to be able to make a comparison.

The only way you are really going to benefit from that mod is if you are doing hard core auto-crossing or track racing. Not to sure you would want to do that with a numbers matching classic.

The rest of the mods are bolt-on's and can be reversed. You could go 1 step further and put on a complete set of tubular control arms like I did and it will go a long way toward making your classic handle more like modern muscle. That would eliminate the need for the offset crossshafts.

You might want to check out this website:

Pozzi Racing

Thanks for the info I did a bit more poking around and that mod will not benefit the type of driving I do. I really do want a set of upper and lower arms but $$$. I've also spent money on rear leafs and year one rally II wheels so gotta hold back for a few months.

I'm only speculating here but I would think the effects of the Guldstand mod would be more evident with a lowed car. Such is the case with using the Hotchkis springs.

If I remember this all correctly the tire goes into positive camber (top of tire leans out/bottom leans in) when compressed. This is bad for cornering and hard nose down stopping. The Guldstrand mod did two things. The A-arm pivot point is moved down and back providing more positive caster and allowing negative camber (top of tire leans in/bottom lean out) keeping the tire surface flat on the ground for hard cornering. Keep in mind the tire will want to roll under during hard corning too.

This mod is much easier to do if the motor is out. I had most of mine together when I did this. I got metal shavings everywhere and made a huge mess. I also had to cut the top of one of the perches for the A arm to clear, and modify one of the back shims to fit by cutting it at an angle.

I put back the factory rubber flaps on the inner fenderwells so you really cant see the leftover holes. And like I said above If I had to do it all over again I may have went with the SPC adjustable arm and tall ball joint. But for the cost of $10 for the Guldstrand book and a couple of drill bits you can't beat the price.

Yeah I agree... The offset cross shafts also add positive camber and eliminate the need for a massive shim stack. I really want her to carve the curves. I hope I can get castor up to about 4 with the shafts and shims. Haven't done much looking into tall ball joints.

The thing I really like about those SPC arms is there is no need for the shim stacks thus you don't have to worry about header clearance or running out of bolt length. Plus who ever does the alignment can get the numbers perfect adjusting the arms. Then there is the fact that they already have delrine bushings I believe.

If you are getting the offset factory style shafts they are not offset that much. I got those as well..

Got the shafts from global west. I've seen those upper before do you have both upper and lowers? I might be able to swing uppers. Global west looks like a good product but like SPC's adjuster right on the arm for castor. You know anyone who's got them used

I tried to post yesterday but wasn't able to. Anyways...
A couple of things to consider: When I went to my tubular control arms I had to go back to the original mounting holes because they wouldn't mount up in the mod location. I'm also running offset shafts but I don't think that had a bearing on the mounting. The original "ears" of the frame might contact the underside of the UCA unless you cut them down or grind them off(glad I didn't because I would've been screwed).
You can run a taller BJ on top and it is effectively the same thing as doing the mod by changing the basic geometry. They tell me you can't do both(taller BJ and Gmod). It would be too extreme.
You get nothing from changing to tubular LCAs except better looks and possibly shaving 3lbs. The stock ones work as well with better bushings.
I liked the SPC UCAs as well for there infinite adjustability but then really how much are you going to change it once you get the settings you like. I went with a traditional tubular UCA from Pro-Touring F-Body.com. He makes them in his own shop in ILL. I liked the fact that I could buy direct from the builder. I figure he will always stand behind the product he makes. Just in case there is a problem I don't have to be able to speak chinese. Probably 4years now and no issues. Nice pieces.
If you want a carver, tires will be where the major difference will be. Doesn't matter too much how good your suspension is if you rubber isn't up to the task.
My .02

Agreed. The real change involves the UCA's only. Lowers provide nothing except a universal fit (across all 3 FGF years) and maybe some small weight savings.

I went with lowers with my uppers because I had a bad lower, went to a junkyard and found a replacement and then later on found out that replacement was bent.