Newbie with a Chevelle

[Berg]

Hey Derek welcome, to answer your driveshaft question all depends on what you are doing with your transmission. If you are just putting in a big block and leaving your TH350 or Powerglide, you'll be able to use the same shaft. If you are going from a 307 with a Th350 or PG you'd need new motor mounts because the 307's use a taller style frame bracket with a shorter rubber mount. They don't have the internal locks to keep the drivers side mount from ripping apart.

http://www.chevyhiperformance.com/te...ech/index.html

Hopefully this link to an old Chevy Hi Performance article works out for you. If not, you can find it by a google search of GM transmission lengths. It has pictures of what you are up against. The main thing with the driveshaft is it can always be shortened by a competent driveline shop for less than half the price of a new shaft. The downfall is that your original shaft probably uses 1310 Universal joints and you'd probably want to step up to 1330 or even 1350's. I have the 1330's in my car with a 454 and a 12 bolt and it seems pretty stout. If you go through the trouble to add the power to the car and then the rear to handle it, but leave the universals as the weak link you may end up replacing your floor pans unexpectedly. I've tossed a few driveshafts, mostly out of lifted trucks and sometimes it makes a mess out of everything. I even had one go through a gas tank. The other thing is the yoke sizes. Th400 uses a 32 spline yoke while the PG, TH350, 700R4 and 2004R use a 27 spline yoke. All transmissions for this car will need a slip yoke, not a bolt-on yoke like some of the trucks have. Just different things to look out for.
If you are going with a manual, 69 and earlier transmissions for the most part had the 27 spline and 1970 and up could have either 27 spline or 32 spline. It also depends on how original your car is and if anything was swapped in the past. My friend had a 68 Camaro that he thought had a 327 with a Th350 but it ended up being a 305 someone swapped in with a Metric 200 out of a late 70's or early 80's Monte Carlo.