2 inch versus 2 1/2 exhaust

[vette427]

:confused I am "doing" my 69 390/427 and part of that is replacing the exhaust system. Can I replace the existing system with a 2 1/2 inch system on the same manifolds? The manifolds seem to be 2 1/2 inches with a reducer as part of the pipe assembly. Has anyone had any experiences with the aftermarket chanbered systems? Thanks and happiest of holidays...joe

 

[Rowdy1]

How Did You.............

Sneak in here? Another Joisey Boy eh? Welcome, you are probably not too far from me. I'm not sure of the size of the manifolds on a big block but you say you have a reducer on the exhaust below them? My theory has always been the bigger the better with an exhaust but there's a lot of air flow theory involved here, scavenging and such. Stock high performance small blocks had a 2 1/2 inch manifold so I'd say you should be at least that. Depending on what you're putting back on it, I'd check in with a big block guy from here. I'd also make sure the exhaust you buy is a good one, some after market systems can be more trouble than they're worth. Let us know how you make out.

 

[WhalePirot]

Can I replace the existing system with a 2 1/2 inch system on the same manifolds?

Joe, I suspect you mean the system after the collectors? My 409cid flows into a 3" system, fed by 1 3/4" long tube headers from TPIS. It works well to the 6300 rpm fuel shutdown.

My '71 454 used Hooker sidemounts which were 4", fed by 2" headers, I believe. My gut tells me, stay at 2 1/2" or larger for the post-collector pipes or your 427 'air pump' won't exhale as well.

 

[pat72]

2 1/2 inch exhaust

:confused I am "doing" my 69 390/427 and part of that is replacing the exhaust system. Can I replace the existing system with a 2 1/2 inch system on the same manifolds? The manifolds seem to be 2 1/2 inches with a reducer as part of the pipe assembly. Has anyone had any experiences with the aftermarket chanbered systems? Thanks and happiest of holidays...joe

I only have a 350 1972 which came with 1 7/8 manifolds so I went to a 2 1/2 inch manifold so I could maintain the stock look plus they breath very well and then 2 1/2 inch stainless all the way back the the flow masters and the difference was unbelievable more horsepower more excelleration and better fuel ecomomy and the sound will blow you awayplus I'm not sure you can get any biggwer of apipe through the frame it was tight ...

 

[vette427]

Sneak in here? Another Joisey Boy eh? Welcome, you are probably not too far from me. I'm not sure of the size of the manifolds on a big block but you say you have a reducer on the exhaust below them? My theory has always been the bigger the better with an exhaust but there's a lot of air flow theory involved here, scavenging and such. Stock high performance small blocks had a 2 1/2 inch manifold so I'd say you should be at least that. Depending on what you're putting back on it, I'd check in with a big block guy from here. I'd also make sure the exhaust you buy is a good one, some after market systems can be more trouble than they're worth. Let us know how you make out.

Yup..prettry close. Over in Flanders/Mt Olive. I don't see how the larger can hurt since the 2" seemed t be a '69 only deal. The manifold and heat riser all measure 2 1/2" ID with the reducer in the pipe. I will cehck the manifold part numbers from '68 since some of those were 2 1/2" systems. I really would like to know about the chambered systems since I had them on my '67 442 and they were pretty nice. I'll keep ijn touch since I would like to meet you one day? Thanks and regards...joe

 

[vette427]

Joe, I suspect you mean the system after the collectors? My 409cid flows into a 3" system, fed by 1 3/4" long tube headers from TPIS. It works well to the 6300 rpm fuel shutdown.

My '71 454 used Hooker sidemounts which were 4", fed by 2" headers, I believe. My gut tells me, stay at 2 1/2" or larger for the post-collector pipes or your 427 'air pump' won't exhale as well.

Hi: No collectors on this one. Each manifold has its own system tith no collectors or crossover. Its sould like my exhaust could certainly not suffer from a little better breathing...Thanks...joe

 

[vette427]

I only have a 350 1972 which came with 1 7/8 manifolds so I went to a 2 1/2 inch manifold so I could maintain the stock look plus they breath very well and then 2 1/2 inch stainless all the way back the the flow masters and the difference was unbelievable more horsepower more excelleration and better fuel ecomomy and the sound will blow you awayplus I'm not sure you can get any biggwer of apipe through the frame it was tight ...

Thanks. I think I will go with a 2 1/2 inch system. How do you like the stainless? I have heard pros and cons on stainless versus aluminized. Do you know anyone who went with one of those chambered systems>
Thanks and regards...joe

 

[Rowdy1]

Souds Good

Yup..prettry close. Over in Flanders/Mt Olive. I don't see how the larger can hurt since the 2" seemed t be a '69 only deal. The manifold and heat riser all measure 2 1/2" ID with the reducer in the pipe. I will cehck the manifold part numbers from '68 since some of those were 2 1/2" systems. I really would like to know about the chambered systems since I had them on my '67 442 and they were pretty nice. I'll keep ijn touch since I would like to meet you one day? Thanks and regards...joe

There used to be a cruise at Paddocks (Auto Parts) on 206, went a few times years ago. Give me a hollar if the salt ever washes off the roads, we'll swap lies

 

[vette427]

Straco (on 206) still has a cruise on Thursday evenings when the weather breaks; In that A&P lot behind Mc Donalds. I'll let you know when that starts again, but you'll here from me before that. I went as few times this past summer. It may be a while before THIS salt is off the road...Sleeting here right now!

My brother-in-law is Palm Springs Ca. is gloating over their 78 F. I am not impressed

regards,,,Joe

 

[Vettehead Mikey]

Thanks. I think I will go with a 2 1/2 inch system. How do you like the stainless? I have heard pros and cons on stainless versus aluminized. Do you know anyone who went with one of those chambered systems>
Thanks and regards...joe

A 2/12" system will fit just fine. The few people I know with chambered are split with opinions about noise level. I have a 2 1/2" system on my small block with flowmasters and find it borderline loud. No chambered for me!

Contrary to what others find I noticed no performance difference between the 2" and 2 1/2" system.

Regarding stainless, it's double the price of aluminized, but either looks like new for decades.

 

[vette427]

Mike: Thanks for the response. MOST informative. I must admit that the 2 versus 2 1/2 is mostly in my head since I would be hard pressed to really drive the car hard enough to notice any performance difference. Maybe some horsing around but certainly little if any sanctioned racing. I will try the 2 1/2 chambered IF I get some positive feedback on the fit. I would rather not have the headache of having someone bend a poor fitting system to fit. Thanks again and deep appreciation...Joe

 

[fine69]

I have a 2.5" exhaust system. It fit perectly. I do have a chambered exhaust. It's not for everybody, but I like it. Here's a clip of it running at idle.

http://video.google.com/videoplay?docid=2385512853798895567

Ralph

 

[vette427]

NICE RIDE!! If I may ask: where did you get the exhaust system?,,,thanks ...Joe

 

[fine69]

NICE RIDE!! If I may ask: where did you get the exhaust system?,,,thanks ...Joe

Joe,

I got it as a complete 2.5" aluminumized dual exhaust system kit from Mid America Motorworks (http://www.mamotorworks.com/corvette?frame=4.1293). Although the kit came complete with all the clamps, etc., I had a local exhaust shop weld all the pieces together. It's a relatively easy install... they fit perfectly. Be sure the purchase the correct tailpipe tips so that you can properly fit them at the same time.

Ralph

 

[vette427]

Fine69: I listened and I like them! I checked the link and I saw these in their catalog as well. Problem is: There is no listing for my 69 big block with the 4 speed, just the automatic? I will call tem and see what mght be available...Thanks again...Joe

 

[Vette79]

As Ralph said, the Chambered Exhaust is not for everybody. I found that they hung a little low at the rear differential. As Ralph did I had a local custom exhaust shop install them with less clamps and a tighter fit. Wonderful sound at WOT!!!

 

[fine69]

Fine69: I listened and I like them! I checked the link and I saw these in their catalog as well. Problem is: There is no listing for my 69 big block with the 4 speed, just the automatic? I will call tem and see what mght be available...Thanks again...Joe

Joe,

Check out catalog #618-630, it's for 1968-69 "Chambered Exhaust, big block aluminized" They have an incredible price - listed at $299.99. Other vendors charge twice that amount.

Ralph

 

[vette427]

Thanks Jeff: I think I will like them. Most of the sound seems concentrated at the end of the pipes with just a nice sound around the rest of the car. How is the sound inside?
Regards..Joe

OBTW. I will take the advice offered here and have the job done. I have enough trouble with the stock systems...jt

 

[vette427]

Thanks Ralph. I totally missed that! How is the volume inside the car?


Thanks again..Joe

 

[rponfick]

One thing to watch on the chambered systems is what you want to attach as an exhaust tip. I have the Mid Am. system on my '69 big block, but the system they sell "necks down" at the tip to allow for stock tips (which are 2"). I had the muffler shop cut off the 2" ends and attach larger diameter tips.

Just something to think about.

Another Ralph.