Muffler upgrade
 

Hello All,

I wanted to share my experience. I would have never believed the difference if someone just told me.

My build is simple. 350 tbi with a small lunati cam
.437"/.454"
207/213 @ .050
250/256
header, 2.5-3" exhaust, stock chip.
https://67-72chevytrucks.com/vboard/...d.php?t=696544

I have been running a 3" high flow cat and a 3 inch turbo muffler (necks down to 2.25 inside) and at 3500 rpms it didn't have a lot of pull left.



I always thought it was the cam or heads causing this. My state lifted the smog requirements so i finally tried a new set up. My motor pulls easily to 4500 rpm now before the TQ falls off. It is night and day different. If I had not driven it both ways i would not have believed it.

The new set up is a glass pack along with a Jones Max Flow.
https://www.summitracing.com/parts/JEX-MF2289



Anyway,, before this I was thinking about a set of heads or a 406 dart block for more stroke. I am glad I didn't. I am excited to see if my mileage increases on my next camp trip while towing.

Chris

Re: Muffler upgrade
 

What is it suppose to do with 2 mufflers attached like that and is it loud or nice and quiet ?

Re: Muffler upgrade
 

I had the glass pack laying around but by itself it is too loud.

I run a Jones max flow on my 78 ford f250 and it sounds awesome but alone it would be too loud for my daily driver.

the two together have a great sound while being mostly quiet. Get in the gas and it sounds great and at cruise i can hardly hear it.

Re: Muffler upgrade
 

The catalytic must have been clogging.

Re: Muffler upgrade
 

That happened to a friends camaro way back in the 80s. That car would barely run and we messed with it for a week until we cut the cat off. Someone probably ran leaded gas in it.

I find it odd that all the turbo mufflers neck down to ~2" inside no matter the ID of the tail pipe.

Re: Muffler upgrade
 

hmmm.... my mufflers are 2-1/2" pipe and id all the way thru..
they are knockoff magnaflows...1 set is magflow, the other is maxxflow after they changed their name
not sure what a turbo muffler is...is that a brand , or just the style?

Re: Muffler upgrade
 

It is style and look like this inside

Re: Muffler upgrade
 

I wanted to double check the cat before i posted again. My cat is 100% hollow inside. Just for show.
All of the resistance was in the muffler. out of curiosity i might cut it open to see what happened. It came from Midas locally because I needed it and they where the only ones with it in stock at the time. (covid).

Re: Muffler upgrade
 

I had a cat disentergrate one time and plugged up my muffler on a s10 blazer I once had, it couldn't get out of it's own way til I changed the muffler

The maxxflows/magflows I have are a straight thru design , the tube inside the muffler is full of holes that I assume is surrounded by some sort of sound deadener, they arnt to bad loud, nice mellow tone
I drew the tube path on mine on this pic

Re: Muffler upgrade
 

The Walker SuperFlow aka DynoMax mufflers are true size all the way through. They are the old Sonic Turbo of the 80’s designed by David Vizard.

Re: Muffler upgrade
 

I've got a set of Walker super quite high flow 2-1/2"...they step down to under 2in as soon as they go into the housing..