Jim78

When dealing with any SBC engine, it is very useful to check the number stamped on the right front of the block, just below the head. There are several sites on line that have the info to decode it. For example, my V1001CLM tells me that it was manufactured at the Flint Plant, on October 1, 1977, 350 CID, Automatic transmission, L48, 185 HP, for Corvette/Monte Carlo application.

The starter solenoid on the Chevy engine is not normally serviced separately. It is integral to the starter motor, and the two are usually replaced as a unit. To determine if the issue is with the solenoid, a voltmeter can be used to determine if it is getting voltage when you turn the key to the "start" position. Another check is to touch a 12V jumper wire to the small terminal of the solenoid to se if the starter operates. But, as your problem is intermittent, this may not necessarily give an accurate result. A shade-tree mechanic approach is to hold the key in the start position (when the starter doesn't operate) and have an assistant tap on the starter with a hammer. If the starter then springs to life, it's time for a new starter.

Another possibility is that the starter solenoid is sticking. Sticking in the retracted position would account for nothing happening when you turn the key. Then, sticking in the engaged position when the engine starts could account for the noise, as it would be the same effect as holding the key in the start position.

On my '78, I simply cut the frame extensions just forward of the body support point. Installed a '63-'64 grill. Quick and easy. Looks MUCH better IMHO.

Here is what you need... https://www.studebakerparts.com/studebakerparts/store/s/agora.cgi?page=avantipwsteering.html&fbclid=IwAR1IN9iSLLKBJTZCrO_Ywzctu9bdbxxP6B6Cmpvp-C8aVIJK-H4kmU1uVc4

When I bought my '78, it had only 24K miles and appeared to be very original throughout. The exhaust system was nothing short of terrible with a really ugly Y-pipe, and catalytic converter shoehorned in. What I found most interesting were the stainless steel mufflers which appeared to be hand welded. I can't imagine that there weren't "off the shelf" mufflers that would have worked fine. Were these hand-made mufflers really original to the '78 Avanti? Has anyone else encountered these? I was cleaning out the garage and found that I still had the mufflers. Is there any value to them beyond scrap?