hey guys, i got a 78 f150 with a 460. its got headers and i had dual glasspacks on it for a few years but they got a little rusty so i installed a set of 3 chamber flows i got from my neighbor. the truck sounds excellent but i lost tons of power! power is important but so is the sound, what should i do? are these mufflers to ristrictive for this size motor?

 

I switched from flowmasters to magnaflows and the difference was night and day. The flowmasters were a little louder but held the motor back, with the magnaflows the tone has changed (still nice) but the motor just wants to rev. Several dyno operators have done back to back tests with flowmasters and straight through style mufflers and the flowmasters always lose a little power, not huge but why give anything away you don't have too.

 

yea i got the 460 for the power and im not gonna give away any to the mufflers. glass packs sound mean on a big block with headers so i think ill put them back on.

 

Switch em out to single chamber flows

Seriously tho, I would write a letter to the kind folks at flowmaster.

"To whom it may concern,

My name is such and such, and have been a loyal customer for many years. I recently made the decision to install new Flowmaster blah blah blah insert part number here mufflers on my 1978 F150 that was my fathers. It was bought new, religiously maintained, and was passed down to me when he died.(insert some heart gripping sob story here) The motor is a stock 460 with a RV cam, and for exhaust is equipped with 2.25" dual pipes(Insert the actual type of exhaust system you have), with headers. Prior to me getting the truck it had glass packs on it, that had rusted out on the inside. When I made the decision to replace the mufflers, I decided without hesitation to use Flowmasters. Once we finished installing the mufflers, I was VERY impressed and happy with the sound. I took the truck for a test drive, and was VERY disappointed with their performance. It was like somebody had put a brick under my gas pedal, and the motor was breathing through a straw. We double checked the direction the mufflers were supposed to be installed, to make sure that we did not make a mistake in their installation. I have used Flowmasters for many years, and have always been impressed with their sound, and the improved seat of the pants performance that I noticed after your product was installed. The truck sounds excellent but i lost tons of power! Power is important but so is the sound, what should i do? I look forward to hearing from you.

thank you

Insert name here.

 

retune the engine for the mufflers, and you will regain the power you lost.

 

Good luck with that. Any engine change should be subsequently checked for tune, but it's been dyno proven (not by endorsed ads) that flowmasters give up some HP to straight through design mufflers or glasspacks when looking for performance. For an everyday driver it's more about the sound.

Here's a little clip I made when I went from the drone masters to the new mufflers.

http://s64.photobucket.com/albums/h1...ewmufflers.flv

 

i tuned for the flows and it helped but i still lost some seat of the pants power. today i put the packs back on with some 3in turndowns, it thunders and the power seems to be back. oh well, the flows were free and the packs are super cheap. ill look for some 1 or 2 chambers next.

 

That's a well done video, my friend! Gives the truck real character, kinda like 'Christine'.
What are you using for oil pressure priming system? Is it air operated?
Have you tried the nitrous out yet?

 

Thanks Trinogt, it's helps me sustain my second childhood

This was the dyno run this summer,
http://s64.photobucket.com/albums/h1...owithmusic.flv

 

awesome numbers! As a word of advice: Could you turn down the background music when the moment comes to put the hammer down? I would love to hear that beast make it's own music!

Also, if you haven't uploaded your videos to Youtube yet, you should. You will likely get a lot of hits! Great stuff, and a great pickup. Keep 'er clean!

 

Flowmasters are awful.. There's a post on 460ford.com about a guy gaining about 30 HP from going from flows (slowmasters) to ultra flows

 

Ultraflows... Is that another Flowmaster product, or something else?

 

magnaflow makes them

I think it's Ultra-flo.

 

anybody got flowmasters they want to get rid of i'll take them. i have glasspacks on my 460 and they wake my daughter up everytime i start it up.

 

flowmasters have better flow than stock. they have a little restriction versus a glasspack. the glasspack has almost no restriction. some places glasspacks aren't legal, too loud. we don't have inspections where i'm from, so it doesn't matter.