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Restrictive Exhaust Question

1K views 13 replies 4 participants last post by  454C10 
#1 ·
I have a 355 SBC AFR 195cc heads with 65 cc chambers, 10.5:1 CR, 600 cfm Edelbrock, XE270HR Comp Cam .495 intake .502 exhaust, 1 3/4 Hooker Headers with 3 inch collectors.
My question is the guy I bought the car from had installed Delta Flow 60 Flowmasters that according to the Flowmaster website are for 6 cylinder cars.
They sound amazing but are they too restrictive and robbing me of any power?
 
#2 ·
What size are they in/out ?? What diameter exhaust pipe & tailpipe ?? I was looking at their online catalog,;
http://www.flowmastermufflers.com/products/index.php?main_page=index&cPath=34_145
There are quite a few different sizes.It could be that the ones meant for sport compacts call for 1 muffler,and I'm assuming that you have duals.If they arent necked down a whole bunch,I wouldnt worry about it.You could always contact Flowmaster about this,
Guy
 
#3 ·
Guy Hiltz said:
What size are they in/out ?? What diameter exhaust pipe & tailpipe ?? I was looking at their online catalog,;
http://www.flowmastermufflers.com/products/index.php?main_page=index&cPath=34_145
There are quite a few different sizes.It could be that the ones meant for sport compacts call for 1 muffler,and I'm assuming that you have duals.If they arent necked down a whole bunch,I wouldnt worry about it.You could always contact Flowmaster about this,
Guy
Exhaust is 2 1/4 inch from the collectors back. Collectors are 3 inch.
 
#6 ·
Well,unless you were to go bigger,(2/12 or 3 inch), all the way from the headers to the tailpipes,this is probably a good exhaust just the way it is.Does it have an X or H pipe in it ??.Theres lots of different opinions on exhaust system size and design.With my 550 hp 468 big block I opted to go with a 2 1/2 Pypes X pipe with cutouts kit,2 Dynomax super turbo mufflers and 2 1/4 tailpipes.It seems to work real good,sounds nice,and I can open the cutouts if I want to go racing.My old exhaust was the same size as what you are running,it seemed to work OK to.
Guy
 
#7 ·
Guy Hiltz said:
Well,unless you were to go bigger,(2/12 or 3 inch), all the way from the headers to the tailpipes,this is probably a good exhaust just the way it is.Does it have an X or H pipe in it ??.Theres lots of different opinions on exhaust system size and design.With my 550 hp 468 big block I opted to go with a 2 1/2 Pypes X pipe with cutouts kit,2 Dynomax super turbo mufflers and 2 1/4 tailpipes.It seems to work real good,sounds nice,and I can open the cutouts if I want to go racing.My old exhaust was the same size as what you are running,it seemed to work OK to.
Guy
It has an H pipe and really does sound nice as i am always getting compliments on how good it sounds. I just want to make sure that they are not causing any power loss due to being too restrictive.
 
#10 ·
Flow masters are very loud and don't flow all that great. Sure they are better than a stock muffler for flow but not as good as a Dynomax super turbo that runs about a forth the volume. Hooker Aero-chambers work nicely, flow about 50% more than a flow master at about half the volume (that is the sign of a good muffler, quiet but flows well). Flow master only has a good marketing name but kind of ironic.
 
#12 ·
454C10 said:
Flow masters are very loud and don't flow all that great. Sure they are better than a stock muffler for flow but not as good as a Dynomax super turbo that runs about a forth the volume. Hooker Aero-chambers work nicely, flow about 50% more than a flow master at about half the volume (that is the sign of a good muffler, quiet but flows well). Flow master only has a good marketing name but kind of ironic.
So in your opinion do i need to consider changing the exhaust and if so what kind of result could I expect by opening up the flow out of the back end? :confused:
 
#13 · (Edited)
We used to use 6 cylinder mufflers on each side of V8's many, many years ago. The only mufflers were glass packs and Smitty's. Our thought was if it would be less restrictive for a 6 cylinder, then it would be even better for the V8. We would run as big pipes we could get. I don't remember, but it might have only been 2" or 2 1/2" pipes. But you could also burn out the muffler too ;) Also muffler placement would make a difference on how noise was inside the car. Farther back, less noise. This was all before exhaust became a science. :mwink:
 
#14 ·
If you like the sound of your car then you really don't need to do anything. Yes, flow-masters aren't the best but the difference in performance between performance mufflers will not be noticeable on the street.

You could drop a tenth at the track with some Hooker Aero-chambers and run quieter while doing it. Or you could run the same time with some Dynomax Super Turbos and actually have a conversation in your car while it's running. Just giving you some more things to consider.
 
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