rocketraider Posted April 7 Share Posted April 7 I had thought all 70s GM stereo radios used 3.5" round dash speakers but those look like 4x6 ovals. The rears do look like 6x9 ovals. Check with crutchfield.com and see what they have. Website lists a number of 4x6 options. Worst case is having to get your existing speakers rebuilt. I've used Jackson Speaker Service in Jackson MI several times and been well pleased. Phone 517-740-0092. I don't think he's ever had a website. 1 Link to comment Share on other sites More sharing options...
NC-car-guy Posted April 7 Author Share Posted April 7 20 minutes ago, rocketraider said: I had thought all 70s GM stereo radios used 3.5" round dash speakers but those look like 4x6 ovals. The rears do look like 6x9 ovals. Check with crutchfield.com and see what they have. Website lists a number of 4x6 options. Worst case is having to get your existing speakers rebuilt. I've used Jackson Speaker Service in Jackson MI several times and been well pleased. Phone 517-740-0092. I don't think he's ever had a website. The front speakers are the 3.5s. The back are 6x9 . Link to comment Share on other sites More sharing options...
rocketraider Posted April 7 Share Posted April 7 3.5" rounds are still produced. Can your fronts be disassembled from their mounting brackets? Link to comment Share on other sites More sharing options...
NC-car-guy Posted April 7 Author Share Posted April 7 Just now, rocketraider said: 3.5" rounds are still produced. Can your fronts be disassembled from their mounting brackets? They come off the bracket. But all the magnets on modern speakers are round, not square like these oddballs. Link to comment Share on other sites More sharing options...
rocketraider Posted April 7 Share Posted April 7 I'd call Jackson Speaker. They'll recone them and make any needed repairs to the voice coil, and the speakers will sound as the factory intended. Plus you won't get into impedance issues. GM factory speakers were 10 ohm back then and most modern speakers are 4 ohm, which forces one to add resistors on the speaker's + terminal to keep from burning out the factory radio's output transistors. ### Looking at the Goodguys NC website reminds me why I let my Goodguys membership lapse. Pricey. Plus the last year I was a member I never got any newsletter or other communication from them, either hard copy or electronic, until they sent my renewal notice.😠 Link to comment Share on other sites More sharing options...
NC-car-guy Posted April 7 Author Share Posted April 7 40 minutes ago, rocketraider said: I'd call Jackson Speaker. They'll recone them and make any needed repairs to the voice coil, and the speakers will sound as the factory intended. Plus you won't get into impedance issues. GM factory speakers were 10 ohm back then and most modern speakers are 4 ohm, which forces one to add resistors on the speaker's + terminal to keep from burning out the factory radio's output transistors. ### Looking at the Goodguys NC website reminds me why I let my Goodguys membership lapse. Pricey. Plus the last year I was a member I never got any newsletter or other communication from them, either hard copy or electronic, until they sent my renewal notice.😠 That sounds like a long process and the factory radio isn't operational anyway. I'll just put it back together and let the next owner worry about it. I'll Keep using my portable Bluetooth speaker Link to comment Share on other sites More sharing options...
NC-car-guy Posted April 7 Author Share Posted April 7 Any ideas how to polish up the trunk emblem? Link to comment Share on other sites More sharing options...
GARY F Posted April 7 Share Posted April 7 try S&M electro tech for speaker. www.smelectrotecj. com I got new ones for my Pontiac. Link to comment Share on other sites More sharing options...
rocketraider Posted April 7 Share Posted April 7 Trying to remember what GM called the clear plastic inserts on their emblems but what they were using in early 70s was garbage. D.L. Auld made those. You can try sanding the plastic smooth(er) and then using progressively finer polishes but it will never look really nice. I've been fortunate enough to find NOS for the Oldsmobiles. It's kinda telling that by the 1980s Oldsmobile's service parts did not have the plastic insert. I don't know if the Buick Tri-shield or Centurion helmet is cast into the lock cover. If it is, ditching the plastic insert and carefully painting the background will look way better than that crazed plastic. 1 Link to comment Share on other sites More sharing options...
EmTee Posted April 7 Share Posted April 7 Yikes -- I hope it sounds better than it looks! 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted April 8 Share Posted April 8 I found some YouTube videos on doing the re-coning process. Not really hard to do, just need the correct size paper items, which might be on eBay. OR check for a local re-coning service that takes care of "dance halls" which use DJs. I suspect that their sources might have access to smaller re-cone parts. I will admit that impedance is still an elusive concept to me, from my high school physics days. Not like like normal resistance, it seems. It used to be that one of the best upgrades to a factory sound system was to use Jensen dual-cone speakers (remember them?), which were 8ohms rather than 10 ohms. The factory radios had no issues with them, by observation. Any current aftermarket speaker will have a magnet AND wattage capacity which are bigger than needed for the factory amps. The larger magnets allegedly take more power to run than the miniature-by-comparison factory speaker magnets. Check out "Friend Google" and see what y'all can come up with. Enjoy! NTX5467 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted April 8 Share Posted April 8 As to the plastic-covered emblem parts, you might check out some of the headlight housing refinishing techniques. One involved sanding (rough to smooth grits) and then using a plastic-rated clear paint over the housings. Basically, remove the oxidized material and then clear-coat the result. Not much money involved, but might work decently well. Enjoy! NTX5467 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted April 8 Share Posted April 8 McGuires Plastic Polish. 1 Link to comment Share on other sites More sharing options...
Smartin Posted April 8 Share Posted April 8 You have to sand the bad plastic off and polish when you find clear. 1 1 Link to comment Share on other sites More sharing options...
NC-car-guy Posted April 8 Author Share Posted April 8 Thanks for all the tips. I'll try polishing the plastic part. As for the stereo, I'm just going to keep using my portable blue tooth for now. $99 each to recone the speakers, or $99 per pair for reproductions plus an adapter to fit the stock bracket (additional cost was not listed). Plus rebuild of the radio. If I keep the car, I'll do the custom auto sound like I did in the 1957. Fits the stock hole but operates like new. For now, I don't want to spend any additional on unnecessary items as my budget is already tight and IF I sell the car, the new owner may choose differently than I would. 1 Link to comment Share on other sites More sharing options...
rocketraider Posted April 8 Share Posted April 8 On 4/7/2024 at 5:07 PM, rocketraider said: Trying to remember what GM called the clear plastic inserts on their emblems but what they were using in early 70s was garbage. D.L. Auld made those. It finally came to me. "Vitrolux". 2 1 Link to comment Share on other sites More sharing options...
NC-car-guy Posted April 12 Author Share Posted April 12 So I used 400 grit then 800 grit, then 1000 grit sandpaper. Then some final polishing with a magic eraser. 9 1 Link to comment Share on other sites More sharing options...
EmTee Posted April 12 Share Posted April 12 Wow - that came out looking nice! 4 1 Link to comment Share on other sites More sharing options...
JohnD1956 Posted April 13 Share Posted April 13 That is very nice Matt! Looked like you had nothing to lose and it turned out great! 2 Link to comment Share on other sites More sharing options...
dmfconsult Posted April 15 Share Posted April 15 (edited) looks fantastic! you should have created a video for that... speaking for myself, I might have been too scared to try that, but as JD points out, it doesn't look like you had much to lose here. Great work! Edited April 15 by dmfconsult (see edit history) 1 Link to comment Share on other sites More sharing options...
avgwarhawk Posted April 15 Share Posted April 15 Nice job! 1 Link to comment Share on other sites More sharing options...
NC-car-guy Posted May 8 Author Share Posted May 8 what "class" would this car be registered for AACA purposes? If I read correctly it's 27j, production vehicles; 1972-1973. Link to comment Share on other sites More sharing options...
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