I'd like some opinions on what I should target for my next upgrade. I'll give you some info on my car
76 L82 350HO Crate Engine, T56 6speed, interior redone, sound system installed, nice paint, new tires, brakes redone, radiator replaced, alot of other misc.
I just drove the car today on a 150 mile trip, checked my mpg and it was around 17, not bad but the car could use a good tune up and I would expect to top 20mpg. My question is in regards to the suspension and the quality of the ride. With the 6 speed I can cruise at 80 miles an hour at under 2000rpm. The ride today on the interstate wasn't bad but there is some vibration and it could be better. The feel of the car doesn't change when I push in the clutch at 80 and coast so I know this is suspension/shock related, but I do experience some chatter when taking off and backing up on some occasions and I was thinking it could be something in the rearend. I'm married with Kids so my projects are usually one a year. I have two problem areas, one I've never replaced any of the suspension parts (bushings, anything). I did replace the shocks sometime back but they were inexpensive ones. Secondly I haven't touched the rear end other than change the fluid and add additive, when I had the drive shaft shortened I did get new ujoints installed on it and they told me the old ones were froze up.

So what would you take on at this stage, upgrade the suspension/shocks or go into the rear with new bearings, possible side yokes new ujoints ect.. I will be getting the car tuned with a new HEI distributor sometime soon, that is my next small job. But after that I need to tackle one of the two problem areas. I've dumped the clutch and smoked the tires a few times, but I don't feel comfortable really getting on it until I know what shape the rear end is in. Where would you spend your money to improve the ride/safety?

 

I'd start with a full inspection under the car, as I'm suspecting one or more U-joints may be the source of vibration/chatter, but there's a possibility you've hurt the diff. (The stock 10-bolt isn't cut out for all that much abuse.) Hope it's just the U's, and replace them with solid/permanently-lubed Spicer's. Beyond that, you really need to consider going thru your suspension and replace any worn bushings, not overlooking the idler arm and tuning up the steering box. Great time to upgrade anything that needs replaced anyway, but watch out that the "while-I'm-at-it's" don't sucker you into a frame off.