muffler and manifold leak advice

BrianB · February 14, 2016, 12:59 PM

I'm going to jump in this thread....

What is a good muffler to replace (looking for stock-type muffler) on the 86 P30? I have round mufflers 7-1/2 inch diameter and 21 inch long. Can't seem to find anything equivalent at Autozone, Advance, or NAPA.

What have you used? (Not shelling out $s for a Banks. Just looking for muffler on back at this point.

DaveVA78Chieftain · February 16, 2016, 10:59 PM

WIll this work? http://www.summitracing.com/parts/mpe-10435/overview/

or you can work down this chain on the right side of the page http://www.summitracing.com/parts/mpe-10435/overview/

hemi354az · February 17, 2016, 12:05 AM

Replacement FlowMaster muffler ? If you want it quiet get a 50 Series Bigblock FlowMaster. If you want it noisy . . . get a 40 Series, or any other thing that FlowMaster sells. See - http://www.flowmastermufflers.com/?page_id=10995, and go to Page 2 bottom. Please consider what you want to "hear" as your drive four hours continuous, break, and then drive four more hours continuous. Zoom. Zoom, Lou FMC #120

legomybago · February 17, 2016, 09:51 AM

"

Rickf1985 · February 17, 2016, 11:14 AM

I was thinking the very same thing last week as I drove eight hours in my Dodge diesel dually with a 4" exhaust and a high flow muffler. It gets noisy after a while and then you go numb to it. You don't even try to listen to the radio. I will be tearing out the interior this summer and putting in a lot of Dynamat. I don't know how guys go with straight through exhaust and then drive all day at speed with it.

legomybago · February 17, 2016, 11:29 AM

In my early 20's I rode Harleys, the louder the better.....Now I'm 40 years old, and they piss me off as they haul a$$ from stop light to stop light....I laugh about it now, and wonder how many people I pissed off back in the day!! Don't get me wrong, I love the Harley v-twin "potato,potato,potato" rumble....Just not at 1,000 decibels breathing fire....I'm thankful I am having the privilege to grow old, so many of us don't.

BrianB · February 17, 2016, 12:49 PM

Quote from: hemi354az on February 17, 2016, 12:05 AM
Replacement FlowMaster muffler ? If you want it quiet get a 50 Series Bigblock FlowMaster. If you want it noisy . . . get a 40 Series, or any other thing that FlowMaster sells. See - http://www.flowmastermufflers.com/?page_id=10995, and go to Page 2 bottom. Please consider what you want to "hear" as your drive four hours continuous, break, and then drive four more hours continuous. Zoom. Zoom, Lou FMC #120

Yeah, I don't see the Flowmasters as being quiet. I don't want to hear it at all with a 10K mile trip.

The only ones I found that even look close to being the right fit are the Gibson ones (http://www.summitracing.com/parts/gib-788706/overview/). I'll have to find a place that can custom bend the tailpipes off the vehicle too.

Rickf1985 · February 17, 2016, 05:55 PM

Instead of buying high performance mufflers get stock replacements for a big block car. Think Cadillac or Lincoln. As long as the inlet and outlet match the size and the length will fit then they are good. Walker is a good brand of replacement mufflers for the stock industry. Any high performance muffler is going to drone at certain RPMs.

Here is just an example from their site. Get the dimensions from your originals and plug them in.

http://www.walkerexhaust.com/catalog/walker-exhaust-systems/universal-muffler-dimension-search

Tailpipes and front pipes are available, mufflers you will have to get by size.
http://catalog.walkerexhaust.com/catalog/resultsDiagramDisplay.do?diagramNumber=13_02060&catalogCode=walkerexhaustasset&locale=en&loadStatus=ACTIVE

kennyrodgers · February 17, 2016, 06:28 PM

Can I jump in on this one as well......
Talking about CATs and the TBI.......can you ditch the CAT on a 94 454 TBI ?? I'm pretty sure it wouldn't need it over here for emissions testing so I'm wondering if it's an integral part of the computer control and if the engine will run fine with it removed.....Phew, I said all that without taking a single breath.
Cheers.

SLEETH · February 17, 2016, 06:47 PM

hi, it shouldn't make diff / unless you have a pre & post cat o2 sensors =if I remember correct that rig of yours should be old enough not to have a pre/post cat o2's .if thus is the case it would not effect your fuel curve at all

SLEETH · February 17, 2016, 06:49 PM

1994 = should be obd1 = with just one o2 sensor = on right manifold if I remember correctly?

kennyrodgers · February 17, 2016, 07:00 PM

Hi Sleeth,
Thanks for the reply....
Just one o2 sensor, it's just at the bottom of the down pipe on the drivers side. Definitely pre cat.
Thanks again.

SLEETH · February 17, 2016, 07:06 PM

u welcome/i use to work on 454 big blocks all the time(for a living) = back when I wore a younger mans cloths!!!
u guys don't have any kind of e-test over there? or e-bobby's?

bluebird · February 17, 2016, 09:01 PM

Why take the cat off? You won't get any better fuel mileage, and it may stink sometimes. If it's bad, I can see taking it off, but if it's still good, leave it.

BrianB · February 17, 2016, 10:32 PM

Quote from: Rickf1985 on February 17, 2016, 05:55 PM
... Walker is a good brand of replacement mufflers for the stock industry...

Thank you Rick for the tip. I just bought 2 from Amazon. I don't think Walker has the tail pipes I need, but I emailed them to check for sure. Also there is a local shop that will custom bend new ones to match the ones I cut off with the torch.

Pipes in front of the muffler look good still. I may change out the donuts on the downpipes when I get up to the front of the vehicle, but that's probably another month away.

Rickf1985 · February 18, 2016, 08:59 AM

Plan on buying replacement studs for the ones that are guaranteed to break off in the manifolds.

kennyrodgers · February 18, 2016, 03:42 PM

Hi Guys,
I was asking more for if it fails in the future and the cost of a replacement over here. If it ain't broke etc etc...
Cheers.

BrandonMc · January 04, 2017, 09:04 PM

Quote from: stopngo on February 09, 2016, 12:33 PM
Are y'all here tellin me you are all still running around with stock 454 manifolds and haven't taken a Grinder to them to make home made headers out of them ?? I did it on mine 10 years ago. You cut out in between each of the 4 exhaust ports and you get a far more positive seal on each individual port than
the stock 1 piece manifold.

Look closely at the pic and you will see what I mean.
http://www.summitracing.com/int/parts/rnb-674-159/overview/make/chevrolet

Well that's interesting. Have these mod jobs held up well enough over time to warrant doing this?

I'm coming back to report that I have purchased, but not installed headers yet due to emissions requirements of the county I live in (maybe someday). In the next few weeks, weather permitting, I will have the exhaust fabricated by a local guy, and installed at the manifold.

2.5" diameter exhaust pipe (DaveVA78Chieftain recommends 2-1/4" as indicated above for his 440 Dodge)
Universal Install Kit
H-Pipe
High performance mufflers

The one thing I'm concerned about now is those high performance mufflers droning on at particular RPM as mentioned earlier by Rickf1985. And here's a review: Load's O Drone - Good sound at idle, Horrible drone between 1600-2100 rpm, I will be returning to Dynomax.

Well, once again, I got too carried away and ordered all these things. Now looking into some other options before I have this work completed. Thanks

BrandonMc · January 05, 2017, 05:53 PM

Quote from: BrandonMc on January 04, 2017, 09:04 PM
The one thing I'm concerned about now is those high performance mufflers droning on at particular RPM as mentioned earlier by Rickf1985. And here's a review: Load's O Drone - Good sound at idle, Horrible drone between 1600-2100 rpm, I will be returning to Dynomax.

Well, once again, I got too carried away and ordered all these things. Now looking into some other options before I have this work completed. Thanks

Did some searching and found this encouraging post.... perhaps I will try these super turbos out after all and report back and give a photo update. Worse I can do is make a 200 dollar mistake either way at this point.

QuoteMufflers... I think I probably could hold the worlds record of different types used on a trifive. I've been driving my car actively since 1998. I started out with some Walker turbo's until they started to rattle.. then I ran some (cheap) Summit Racing house brand turbo's for a time. Decided to get on the Flowmaster wagon with a set of Delta 40's (and added a H-pipe). Liked the sound of the FM's, but, the interior drone was awful. Moved to Mississippi, and had some Edelbrock's installed. They had a very cool sound for about 6 months, and the inlet pipes on both of them came loose from the main body.. then I went back to FM's, this time the Delta 50's. I actually liked them (alot).Got a new wife.She HATED the FM's. What does a guy do for a new wife that hates FM's?He goes muffler shopping... again...
I've now settled on Dynomax Super Turbo's 17748. Ended up finally changing out my old headers with Hooker Super Comp's, JetHot coated, new pipes (H also) and (2 1/2") tail pipes. I (think) I'm finally settled. Interestingly, I've gone full circle back to pretty close to what I was running from the git-go. Do I like the Dynomax's? Yes in a word. No drone, fairly quiet... and happy wife.

but then, I see this:

QuoteThe dynomax super turbos get louder as they are used more. My friends were fairly quiet when new but two years later I can hear him coming from a mile away.

BrandonMc · January 19, 2017, 08:08 PM

Hi,

I just wanted to make a note that if anyone was following, or otherwise will be interested in what I did with my 87 Chieftain, and '88 P30 chassis exhaust, I recommend reading this report.

Thanks for all your input here RICK and DAVE!! I expect I can save some people a headache and some money.