Cadillac Owners Forum banner
  • Hey everyone! Enter your ride HERE to be a part of September's Ride of the Month Challenge!
1 - 9 of 9 Posts

·
Registered
'94, '93 & '76 FWBs. '77 '79 & '73 CDVs, '65 Drop, '62 CDV
Joined
·
414 Posts
Discussion Starter · #1 ·
Guys,
Will a dual exhaust fit under the frame of a '65 Convertible easily? If so what's the recommended pipe size for the 429 motor - 2 1/2 single pipe, 2 1/4 duals?
The existing system is a bit junky so I was going to replace it with a decent mandrel bent system in stainless from a locally well known bender so I only want to do it the once but well.
Also what kind of boxes would be preferred for flow and quietness? I put Walker Dynomax ones under the 94 and it seems pretty quiet. I want the whisper quiet Caddy ride but with good flow, not a big shouty thing.
Cheers all! :caddy: Nick
 

·
Registered
68 DVC, 96 FLTWD Brgm, 11 CTS Premium (two)
Joined
·
1,729 Posts
It should fit easily. I had my 1968 done in dual - might have to locate the final segments on the other side of the frame rails. also, getting a full size resonater in could be difficult.
 

·
Super Moderator
2014 ELR
Joined
·
10,487 Posts
Use stock Cadillac mufflers if you want quiet. They are big, heavy, and quiet. However, they flow decently. Smokey Yunick used to recommend them for street performance in the 70s/80s
 

·
Registered
1959 Series 62 Coupe
Joined
·
13 Posts
It always amazed me that these cars came with a single exhaust setup. It seemed ineffective for the sheer magnitude of the V8s.
 

·
Registered
'94, '93 & '76 FWBs. '77 '79 & '73 CDVs, '65 Drop, '62 CDV
Joined
·
414 Posts
Discussion Starter · #5 ·
Thanks guys!
Good to know it will go in. I was worried about sufficient space under the trans crossmember.
What size of pipe for hte duals please?
Standard Cad mufflers - OK, which ones exactly please? 'Heavy' could be an issue since I plan on taking them back on the plane in a couple of weeks time. Also I was planning on a stainless system. Are there any recommended high flow & quiet stainless mufflers?
And what resonators would you recommend? Dod the resonators keep the the quietness down? I've always had standard resonators on the rear of all my systems.
regards & thanks, Nick
 

·
Registered
1970 Coupe DeVille, 2002 Eldorado Collector Series
Joined
·
200 Posts
2 1/4" would probably be fine, but I'd still go with 2 1/2". Either system will flow more than your engine needs. Think about putting in a crossover too, it'll quiet it down a bit, give it a more refined sound, and flow better too. 2 1/2" with a crossover and Flowmasters is what I put on my '70. Louder than you're looking for, but still a beautiful thing. I agree, they should have come with duals from the factory. Strange at the height of the muscle car era that they didn't.
 

Attachments

·
Registered
'94, '93 & '76 FWBs. '77 '79 & '73 CDVs, '65 Drop, '62 CDV
Joined
·
414 Posts
Discussion Starter · #7 ·
Intragration,
Thanks - nice pic! Says 1000 words! I see the kick up in the trans cross member drivers side and passenger side for the exhaust. Pass side I was expecting but driver's side not. Is this standard? I know your's is a '70 but is the frame on the 65-70's the same? Sorry I don't know if this si the case? And is the double humped trans cross member standard?
OK - so I think I'll put on a dual 2 1/2" system in stainless with 20" long offset outlet Walker Dynomax super turbo muffs in stainless, no resonators and nice turndowns uner the bumper.
Sond good flow and quiet?
regards & thanks, Nick
 

·
Registered
1970 Coupe DeVille, 2002 Eldorado Collector Series
Joined
·
200 Posts
I don't know if this is how it was for '65. Best to just take a look. If you want whisper quiet, you might want to go with some sort of resonator too, and a more stock muffler. If I was going to put a resonator on my car, which I may still consider, there is something called a race bullet, which is a tiny resonator that doesn't do much, but helps a little. I think the system you described would sound nice and not be too loud, but it would be louder than whisper quiet. Don't forget the crossover too, I think you'll like it.
 

·
Registered
'94, '93 & '76 FWBs. '77 '79 & '73 CDVs, '65 Drop, '62 CDV
Joined
·
414 Posts
Discussion Starter · #9 ·
Thanks, apparently (Bruce in Tasmania was telling me this morning) that the standard original system had a 4 foot long resonator in a style similar to the Dynomax Race Bullet you mention from the front of the trans along the side of the trans tothe tailshaft. Four foot! and then a muffler by the rear seats and no tailpipe resonator.
Still don't know if/ how dual exhaust was an option though. I'm pretty sure it was on the Eldos.
regards, Nick
 
1 - 9 of 9 Posts
Top