Exhaust swap = performance

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Jan 20, 2005 | 12:13 PM

lovemy6

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Exhaust swap = performance

84 F150 w/ 300 I6 - If I keep my stock intake & 1bbl carb, what kind of performance increase should I see by switching to EFI (split ex. manifold) & running true duels with Flowmaster or Dynaflow mufflers? What would it sound like?

Jan 20, 2005 | 01:25 PM

HunterSThompson

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From: Denver, Co

It will double your gas mileage - make it pass everything on the road like they are stuck in low gear, and women will be like putty in your hand.

Ok maybe not,,,,,,,,,,

It won't hurt ya, but it won't help a lot. In fact you will loose the warm air off the single exhaust, so it may be grumpier when it's cold. (That should be lots of fun!)

Do it anyway - you know your going to want a cam and a 4 bbl - and more compression some day.

Jan 21, 2005 | 08:23 AM

lovemy6

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Thanks for the reply. I'm in Arkansas, so it's really not that bad in the winter, but I thought the same thing about the cold weather & wondered how hard it would be to start. I took my stock manifold off to clean everything up a little & discovered the flapper (heat valve) in the stock exhaust manifold was not working anyway. It turns on the rod w/o the rod moving. So it has not been working anyway. We have had colder than normal weather this year & it's not been a problem so far. I'm going to go ahead & do it. I will be stepping up to a 4 bbl in the future. Doing it a little @ a time so my wife wont be in shock with how much money I'm putting into the truck.

Jan 21, 2005 | 12:45 PM

MRStace84

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It will be grumpier when cold. Mine has to run 15 to 20min to even appear to be running close to right. However, when you get all of those mods done, you won't really care. With the 4bbl and mainfold upgrades, you press the gas and the truck moves!

Jan 21, 2005 | 12:51 PM

lovemy6

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It will be hard to do i'm sure, but if i can keep my foot out of it, what should swapping 4 a 4bbl do to my mileage? I'm only getting about 10 now.

Jan 21, 2005 | 01:51 PM

Schmids4.9l

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From: Bored town OH

if you get 10 mpg on a 1 barrel, i wouldnt get a 4 barrel, even though i got efi and im not to smart in the carb world, i wouldnt count on getting better mpg with a 4 barrel.

Jan 21, 2005 | 06:26 PM

project supercab

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From: Churchville MD Harford co

EFI manifolds and 4 barrel (390 holley) makes great mileage over stock
dont know why but it does
maybe cause of the gain in efficiency (less restriction)
this setup hates the cold though