Need Some Guidance on Exhaust System

[gzig5]

I need some sanity brought in.  I've been spinning around in circles for days on how to proceed with an exhaust system.

Car is a 73 Cuda with 71 340 motor and 727 automatic.  J-heads, not sure but think they should be 2.02 intake valves.  Edelbrock LD4B intake with a 650 double pumper.  No idea on the cam at this time.  Currently has a set of crusty Heddman/Flowtech style long tube headers which feed into a set of long Cherry Bomb looking glasspacks right off the headers and then that's it.  No pipes past that, just the ends of the mufflers hanging there.  Three of the tubes on the driver side header are dented in from bottoming out, one of them is probably 80% blocked.  I'm trying to get the car driveable and for that it needs a new gas tank kit, holes in the trunk patched temporarily until I do it right, a reasonable exhaust, and then bleed brakes and make sure the suspension is safe and all those other little things.  I have a very limited budget this year to get it on the road.  Wifey is not as cool with it once it came home and I started talking dollars fix it up.  Seems she had the idea it was ready to go, I've no idea where that came from.    I've got a semi-hard budget of $2k in parts to get it on the road. 

Good news is I have a brand new set of ceramic coated Heddman headers that came with the car.  Bad news is I don't want to put them on because they are likely to get whacked like the old ones, especially if I lower the front like I'd like to. I'd ultimately like to go to Doug's or TTI headers but that is going to blow my budget if I do it now.   I'm 95% sure I can repair the set that is on there, maybe even with them in the car.  I remember what a bitch it was installing this style 30 years ago on my first Barracuda and will avoid that if possible.  Worst case I bit the bullet and install the new set that is on hand.

TTI has a nice exhaust system that should bolt up and at $680 isn't totally unreasonable. There is a local distributor so I think i can save the shipping.  I'm looking at 2.5" diameter, I don't think I'll get this motor past their capability in the next several years.  Should easily handle 500hp right?  The Accurate Magnum sound good and I like the idea of using the original style resonators and round mufflers in the stock locations, but I think I'd be over $900 by the time I add intermediate pipes and the rest of it. Are there other Exhaust systems I'm missing that work with headers I should be looking at?  The house brand stuff at Summit and Jeg's didn't look too appetizing.  Any custom mandrel bent setup from a local shop is likely to go at least $1k, Midas quoted $600-800 not that I would ever use them.  Just want to make sure that whatever I go with will work with Doug's/TTI headers down the road.

I considered going back to stock manifolds or shorty headers temporarily but that is a false economy I think.  Doesn't solve the exhaust question and just complicates it for later.

Probably the cheapest would be to throw some pipes and cheap mufflers/resonators on top of the cherry bombs but I don't know how that would sound, and working from a generic kit is a PITA.  I made a muffler delete kit for my 2000 BMW M5 (for sale btw) from mandrel bends but it was a lot of fiddling.

I will need square tips through the valance, but I want to try my hand at cobbling a set first before I buy.  Ideally the exhaust would line up with the openings in the valance but I don't know if that is possible with these off the shelf systems.

Sorry for the long rambling post.  As you can see I'm spinning myself into the ground on this.  Appreciate any insight or grounded reasoning on how to proceed without blowing the budget.

[Bullitt-]

 

yer obviously not up to speed on header tech

[gzig5]

I've seen that.  Makes me think that two of the tubes are probably OK.  The outside tube is really crushed though.  It looks like an inverted U for about six inches.  Can't be much more than 1/4" clearance through that section.  I think it's going to affect it.  That header needs to be fixed or swapped.

[303 Mopar]

You are not going to get good quality and the sound you want on a super tight "wife is watching" budget.  The cheapest is to keep what you have and enjoy it the way it is and save you pennies for a complete TTI exhaust system. There have been many have have had issues with heddman headers.

Next is to keep the headers you have on, buy the cheapest mufflers you can find, take it to a muffler shop or find a friend with a welder, and weld on collectors to the mufflers and dump the exhaust before the rear axle. Many choices between this and a complete TTI exhaust set up, which is the right way to go IMO. Do it once and do it right.   

[kathyscuda]

buy a pair of orig 340 hipo manifolds
complete accurate exhaust system.
you will never have to worry about leaks or crushing anything goin over a speed bump.
F.A.S.T class cars don't run headers.

[Burdar]

buy a pair of orig 340 hipo manifolds
complete accurate exhaust system.

Estimating the cost...
73 340 manifolds $400ish?
Accurate exhaust $700-800

Not a bad option but it blows most of his 2k budget.

[72 Challenger]

I have a buddy that needed to get his duster moved quick and cheap as the result of a divorce.

He bought a used dual exhaust system off a local classified website for a pickup truck, it was ~50 dollars. He re-purposed the pipes and mufflers to make a system that dumps just before the rear wheels. It was not going to win any shows but he drove it that way for years. Used exhaust systems are worthless. Also, bulk exhaust piping is cheap. If you have some basic welding tools and skills, this is not a hard project but may soak up some time.

I'd just re-use the headers as is and keep pinching pennies till you can make it what you want.

[HP_Cuda]

It depends on how low the new Hedman headers sit. You could take to it an experienced exhaust guy and have them do some magic on it to pull the collector up higher then dump the rest into mufflers and a new exhaust system.

As I remember it 2.5" exhaust is good up to 600 hp so it might be overkill for your 340 and you want backpressure:

https://www.roadandtrack.com/new-cars/car-technology/a14530205/what-is-exhaust-backpressure-and-why-is-it-bad-for-horsepower/

[gzig5]

Thanks for the comments, they have been very helpful and in line with where I was leaning.  I've made the decision to repair the current headers and leave them in (if possible).  I will buy a 2.5" pipe kit SUM-680139-NM from Summit (unless there is a better suggestion) and a set of Dynomax mufflers.  That will set me back about $300 plus various hangers and I'll have a decent enough system that exits at the back of the car instead of under my seat.

I called TTI and the nice lady there gave me the model number of the Dynomax that they design the system around, #17733 for a 2.5".  It's right there in their literature but I didn't realize that they are using Aluminized carbon steel and not 409 stainless for their exhaust pipes.  I guess I assumed that at that price point it would be stainless.  I guess no one is having any rust issues and I doubt these cars ever get driven in the snow/salt/wet anymore so probably not a problem?
Tomorrow I order the exhaust stuff, new gas tank kit from Roseville, and a new Hobart 190 welder to stick it all together with.  The welder doesn't count towards the car part budget, it was already planned and saved for.  

[Chryco Psycho]

Small block headers are mostly just bad in design
there are only 3 that I am aware of that stay above the steering link
TTI
Dougs &
Hooker 5115
everything else seems to drop below the center link & will last about 10 mins Before the lower tubes get flattened .
as for the dyno I would have loved to see them flatten one of the tubes right at the bottom & the lowest point to see if it cared down there .
IMO spend your money once & do it right , meantime you could bolt on a set of log manifolds virtually free or use the magnum manifolds from a wrecker .

[RUNCHARGER]

I was going to suggest the Summit deal but you found it. I think you will be getting the best you can for a cheap price. I've headers before and it's a pain but it will get you through the season I imagine. TTI's are the way to go in the end but they aren't cheap.

[Brads70]

I've had this system on my car for 10 years now with no issues.
https://www.summitracing.com/int/parts/mpe-15851/overview/year/1970/make/dodge/model/challenger

[gzig5]

Small block headers are mostly just bad in design
there are only 3 that I am aware of that stay above the steering link
TTI
Dougs &
Hooker 5115
everything else seems to drop below the center link & will last about 10 mins Before the lower tubes get flattened .
as for the dyno I would have loved to see them flatten one of the tubes right at the bottom & the lowest point to see if it cared down there .
IMO spend your money once & do it right , meantime you could bolt on a set of log manifolds virtually free or use the magnum manifolds from a wrecker .

I do like to buy once and cry once, but in this case I just can't commit at this point.  I considered log manifolds but it seemed everything I looked at was $100 per side and I thought I saw a thread where the Magnum's get awful close to the power steering box?  If these old headers happen to get beat up again I won't feel bad and I think the budget should be in better shape next spring to go whole hog.

I too would like to see the Dyno of the common damage to headers from speed bumps etc.   My weak understanding of air flow dynamics tell me that a short length pinch point is less disruptive than a longer length restriction that isn't as tight.

[gzig5]

I've had this system on my car for 10 years now with no issues.
https://www.summitracing.com/int/parts/mpe-15851/overview/year/1970/make/dodge/model/challenger

Do you have a video or sound clip of your car? Curious what the sound volume/quality of the Magnaflows is like.

[Brads70]

I've had this system on my car for 10 years now with no issues.
https://www.summitracing.com/int/parts/mpe-15851/overview/year/1970/make/dodge/model/challenger

Do you have a video or sound clip of your car? Curious what the sound volume/quality of the Magnaflows is like.

Sorry no I don't.    It is not bad , kinda quiet idling around but somewhat aggressive then you pop the cork ?