And then there's this, I found that chart previously but thanks for linking again, this issue slipped my mind. I *think* there is a 14" disc kit that will work with the drum wheels, but I'd have to search for it again. I'm not necessarily stuck on 15's so a 16" or 17" tire is just as much of an option. I hadn't considered 15" being that limited but I haven't done a lot of shopping for them either. I just don't want something that would require a short sidewall to fit or look too big for the wheel well.
My GS just out the paint shop (fender emblems not installed yet), on 18" ARE Torque Thrust 2 wheels...stock height suspension. Plenty of clearance for my longtube headers, and no rubber bands for tires. 60-70 series sidewall may seem normal to many, but there's SO much slop and wallowing with stock height tires on 14 or 15" wheels. Just a swap to larger wheels felt equivalent to a complete suspension upgrade. I can get tires from any tire shop, in many different brands, as opposed to three different brands with the 15's.
It depends on what your "big picture" is for the car. Are you going for big performance, or a daily driver that won't see a lot of miles per year? And, of course, you have to consider your budget for the project. Have you allocated enough money to buy five new 18" wheels and five new tires and a disk brake kit? If so, and that's the track you want to follow, go for it. If your budget is begging for mercy at the thought of that kind of expenditure right now, you have four brand new tires that you can burn through while you're deciding what you want to make of the car. The GS 400 should have come with aluminum front drums. If yours doesn't have them, you can pick up a set of those for less than the cost of a DB kit, and they will make a considerable difference in braking performance compared to all cast iron drums. I have a '66 Special that was all cast iron, and as Harlockssx stated, stopping the car with a 455 pushing it down the road made my eyes as big as dinner plates a couple of times. I have a '67 GS parts car that had the aluminum drums, so I decided to throw those on the Special. The braking performance improved enough that I decided to wait on the DB conversion until my budget recovered from the shock of rebuilding the 455. I also agree with dukec on replacing everything from the master cylinder to the hubs if the DB conversion is down the road some where in the future. Make sure everything is adjusted up - they used to say that the brakes were adjusted correctly if the wheel didn't spin more than a quarter turn when spun by hand with the wheel off the ground. Then, as long as you're not driving like a crazy man, you should be able to drive the car with some level of confidence in the brakes.
Big picture? Not worried about an all original car, not going for a street racer or a show car but a good driver. You're on the mark about budget, I would figure a pretty good chunk of change by the time I get new wheels, tires and a DB kit. I just finished doing a DB swap on a '68 truck and had lots of little things that adds to overall cost as well. Would a drum/drum MC work on a disc/drum setup? (It didn't on my truck). Replacing the drum brake parts on the front doesn't appear too pricey and rubber lines and a new MC isn't bad either. This path, for me, would likely be the better way to go until I get all of the funding together to get it done at once. Thanks for the input.
