New mufflers help
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Senior User
Joined: Jan 2007
Posts: 242
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New mufflers help
I am going to buy some 40 series flowmaster mufflers for my 68 f-250 with a 360 in it I am going to have an exhaust shop completely redo the the tubing and I was wondering what you guys think is the best size to go with. I was thinking 2.50 also if anyone could tell me what inlet and outlet I should get on the mufflers?
Fleet Mechanic
Joined: Dec 2006
Posts: 1,338
Likes: 6
From: UPSTATE NY
interesting question. i also have a 360 v8, and i'm running hooker headers with cherry bombs and 2" pipes poking out in front of the back tires, true duals, looks great, sounds great, but i was thinking 2" is kinda small and wanted to go to 2 1/2, sorry to jack your thread, but maybe this will give you some ideas for your project as well as get some ideas about mine.....
anybody know what size the pipes need to be for optimum flow? at what point are you getting held back and getting backpressure? 1 3/4 maybe?
anybody know what size the pipes need to be for optimum flow? at what point are you getting held back and getting backpressure? 1 3/4 maybe?
Senior User
Joined: Dec 2006
Posts: 281
Likes: 0
From: Woodstock, Portland, OR
i'm pretty sure I have 2.25 on my 68 f-250 w/ 360 v8. i'm also running the longest glass packs they make. haha. makes for some good flow, and some good sound. i think if you go much bigger than that, you'll start loosing too much back pressure and your engine will run crappy.
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Post Fiend
Joined: Dec 2003
Posts: 6,658
Likes: 4
From: "Islander"
With a basically stock 360, stock cam low compression w/2 barrel even with headers the gas flow isn't there to fill 2 1/2" piping.
Go with 2 1/4" unless there are plans for a mild 390,410,428 in the future.
On glasspacks those with louvers tend to choke up increasing in restriction as the gas flow increases due to the turbulence from the louvers, installing them backwards helps reduce this at the cost of increased sound.
If your set on having glasspacks go with the ones that have a perforated tube on the center for better flow and run a balance pipe "X" pipe preferably.
Keep the system one size including the mufflers, long cone stepdowns on collector cones vs the sharp size drop as most headers end with 3" at the collector.
All the above for a "standard daily use motor", if hot rodding is the intended use different size piping should be used.
Go with 2 1/4" unless there are plans for a mild 390,410,428 in the future.
On glasspacks those with louvers tend to choke up increasing in restriction as the gas flow increases due to the turbulence from the louvers, installing them backwards helps reduce this at the cost of increased sound.
If your set on having glasspacks go with the ones that have a perforated tube on the center for better flow and run a balance pipe "X" pipe preferably.
Keep the system one size including the mufflers, long cone stepdowns on collector cones vs the sharp size drop as most headers end with 3" at the collector.
All the above for a "standard daily use motor", if hot rodding is the intended use different size piping should be used.
