I bought this car 2 mths ago, from Fla (the salesguy lied about several items, but still got an "Ok" deal). In a nutshell, it has a $600 hi-po al radiator, RPM intake, Holley carb, headers, true dual exhaust (saleguy said it was a new Magnaflow), on a regular L48 motor with nothing done to the motor, runs terrible, it actually sounds good though. I like the sound, a lil mean sounding without being way loud. I am buying the TFS kit https://www.trickflow.com/parts/tfs-k314-445-405 and having a mechanic install it.
Didn't think i was going to mess with the headers (I have no clue the mfr) and exhaust, but I got underneath for the first time and ran the #'s off the exhaust and they are Summits straight pipe, and 2.25.
https://www.summitracing.com/parts/a...a7514#overview

I need some exhaust quick, Magnaflow the best option? Any cheaper that sound good/flow good?

 

Had Magnaflow mufflers on 3 different cars and was happy with all 3. None Corvettes, though. I can't imagine you won't be happy with them. Definitely not a fan of Flowmaster.

 

I've never been a fan of them either, had them on a GT Mustang numerous yrs ago and had them changed after the first day, but I really like the sound of this car. Solved my Exhaust deal, a buddy had told me about this local shop doing great work on his 68 Camaro, called them, $650 for custom exhaust, and up depending on Mufflers/Tips, I'd like to use the same as I really like the sound/tips (If it 2.5" which he said most are, even though my pipe is smaller). Not sure I'll beat $650 for custom exhaust, vs the $1100 plus Magnaflow/Pypes etc want, plus labor to install.
Probably do the Headman headers that have a few good reviews here.

 

You need to crawl back underneath and see if the transmission cross-member has two holes for the exhaust.
Some models do and some models . . . . . . . . . . . ?????

 

Hey HeadsU.P, I'm in good shape there, as it does.
I'm also going to call one of the few places here in Houston that does Mandrel bending tomorrow to compare, I'm not sure how important that is (I was always told it was), but the place is sorta close to me, so if the price is about the same, that's be a no brainer.

 

I'm on the north side in spring, Bobs Auto Express does a lot of corvette exhausts

 

I just finished getting Corvette Central's N11 system on my 69 with a mild 350. Haven't had it on the road yet but fit is excellent, price was reasonable, and very happy with the sound.

 

I've heard of Bob's, nothing but good things. I was going to use Ripleys, as they are shown to be one of the only shops in Houston that Mandrel bend. Using my mufflers (FM 40's, 2.25 but he said that doesn't matter as they can run 2.50 in without any reduction), which he said saves $400, is $800 for aluminized, 1200 for SSW, and 5K for Mandrel.
I no longer need mandrel bent as much as I thought, lol. Wow! I mean I get it, I know theres a ton of extra work/expensive machine to pay for, but I didn't have a clue it was that much. He said there is a 25% reduction in non mandrel bent. What do you do then, put 3", then, if that's correct, will put it back at 2.25, which is what I am starting with.

 

Then there is my header issue, looks to me like the ones on it are Summit headers, looks to be of same type of design. They are gray, so someone painted them with that high heat paint I believe. I like the sound, and I'm sure they provide good flow, but I have straight spark plugs currently (they show to fit only straight on Summit site) and will be buying a TFS top end kit that ONLY has angled, so I may have to replace. I wasn't planning on replacing either, the exhaust or headers, but here I am.
Is it Dougs that fit the best?
It doesn't look that like the started or Idler arm was in the way of these Summits, both runners at the middle spark plug (each side) are dented in some though.

 

Can't understand how a mandrel bent exhaust can cost 5k for a vette.i had a new 3" system installed last year for $650.00 labor. the person installing the system had me purchase the parts and bring them to him. 2 ultraflo mufflers were about $75.00ea the pipes (aluminized) i think i got 3 - 48" pcs and 2 j-bends and 2 - 45* bends for under $200 - i can't remember exactly and 3 or 4 hangers. altogether the whole system was under $1k. you can check the prices on Jegs or Summit. and stainless pipes are not a whole lot more unless you want them polished. you should be able to find someone who is a good welder and has done this before. no way should it cost $5k for a exhaust system. besides the magnaflo system the pypes system look pretty good also if you want to purchase a complete system but you will still have to have a custom pieces made up to connect to the headers
Pat

 

I would buy a system made specifically for your Corvette but mandrel bent is not always a requirement in my world. I have 2 Corvettes and both have Chambered Exhaust systems that were made for the specific years Corvettes and I was able to install both systems at home. I also chose the Aluminized Steel and both Corvettes still have the same systems on the cars. I would not waste my time buying Stainless unless there is a big discount on it. My Chambered Aluminized Steel systems are both over 2 decades old and are in great shape. Both my systems were made by Allen's Stainless Exhaust which is no longer making exhaust systems. I paid less than $500 for each system and as I mentioned earlier I installed them myself in my driveway.

I am not sure if the sound is is critical to you. I love the sound of side-pipes but can't hear anything after driving in a Corvette with them for hours. The Chambered Pipes are simple and straightforward as they don't use bulky mufflers in the rear. The sound deadening is done inside the pipes themselves and they sound almost like side-pipes but the noise/sound is going out the rear of the car. My C3 with it's 427 sounds incredible and the 1988 C4 even sounds like it actually has horsepower. My L98 is rated at 245hp and sounds like a really powerful engine from the sound alone.

A good flowing exhaust does help your engine. Having headers is much more important if you buy a high flow exhaust system. I have long tube Hedman headers on my C3 and the engine makes plenty of power with the Chambered exhaust as it is UN-restricted and flows very well. I do not have any cross-over pipe in between the right and left sides which seems very popular today as people claim it helps make power.

 

I hear you, and I agree on the Mandrel, been doing some research/asking gear head buddies, since I'm not building a race motor, I'll be fine. I'm going to do the custom, went to Ace here in Humble (where I live), a cpl buddies recommended them, and they have decent reviews. For around $400, he'll install 2.5" from headers to about a ft before the mufflers (said the previous shop already welded into it and he can't do the 2.5 into it, but said since its at the end it won't make a difference being 2.25 there), I like that!
Sound is critical, and as stated above, I really like the sound now (why I'm kinda leaving it as it except the larger pipe). I think side pipes look/sound really cool, on certain car, mainly the eralier (late 60's/earlier, even mid 70's), but not so much on mine. I'm going to leave the headers as they are now (even the exhaust) till the new top end gets installed and see what we have for fit. I'm not doing the cross over thing either, did it on my last TA, but going to do straight through duals here.

Do y'all agree it doesn't make much difference going from 2.50 to 2.25 right there at the muffler? My buddy I just ate lunch with, said he agrees, but even farther, said he didn't agree I needed the 2.5 at all, but it's my $, lol.

 

I recently bought a slightly used chambered system off Marketplace (FB).
The previous owner said he paid $900.00 for it, but didn't say who made it.
I couldn't find the manufacturer by searching the web. What I did find (Pypes, etc) were
all straight pipes, while these down tubes and the chambered pipes had mandrel bends in them.
I'm thinking it was custom made. Cost me right about $300.00 total.
with the extra hangers and clamps I bought. Installed it at home.

No mufflers. Manifold down tubes start at 2", and flare out to 2.5"
Chambered tubes are 3"

 

If you really want to understand exhaust component differences look up Engine Masters episodes on exhaust. They put everything to the dyno test; various headers, dented headers, exhaust length, cheap mufflers that work well, mandrel bent. Even for a performance enhanced L48; if you already have true-dual, no cats and straight thru mufflers; you wont notice going from 2.25” to 2.5” diameter pipes. A 2.25” restriction at the end of 2.5” exhaust will increase back-pressure. If you like the sound the way it is, might be good to not change it. There are plenty of other performance upgrades to spend your money on. If you do change the pipe diameter the fundamental exhaust note will change; adjusting length will get it back in tune; charts exist for that. Think pipe organ, each diameter has a corresponding ideal length for best sound. If you like the option of sounding really rowdy, include cut-outs.
Charlie

 

I hear you, if I was leaving the L48 alone, I wouldnt even be considering exhaust, but I am putting the top end kit that is in my OP, or similar (I am making cpl of subs).

 

We installed magnaflow and mandrel bent 2.5” true duals on our 1978 and we love the sound and the engine seems to be more responsive.

 

last year I had installed 3 inch exhaust with manaflows, total cost $900 at a custom muffler shop.

 

Didn't you have to some fab worm as well to get 3" to fit? I'd like to, but I have a 79 with the pipes going through the crossmember (that's welded in cause i have a 4 sp). I'll do the custom 2 1/2 whenever my engine gets installed.

 

not at all, I have a 4speed, it's through the cross member...