I've been thinking about putting some hedmen headers on my 81 f100 with the 300 inline 6, and running true duals, and I decided I want a crackly exhaust, as in, you rev it up, lift off the gas, and it crackles as the rpms drop, I would show you the exact video I got the idea from, but the guy that posted the video on youtube took it down, I have been told from comments on youtube that, to achieve this, I would need short cherry bomb glasspacks, that are mounted closer to the headers, to get a crackly exhaust, I need some input from you guys on this, Thanks in advance!

 

When you mentioned "crackly exhaust" I thought of glasspacks. The good thing about glasspacks is that they're generally the cheapest mufflers you can buy. I suggest you take your truck to a local exhaust shop and tell the owner what you're looking for. Exhaust shops often have house brand mufflers/glasspacks that can save you money too.

 

I bet he will never find a shop to modify the exhaust like that. Against the Fed law and they won't touch it. The dual outlet header he buys will be for "off road use only".

 

Come to think of it, you can't really get "true duals" with a straight 6. Like Dave mentioned, you might run into emissions laws depending on where you live. You could probably get away with running cat back duals though.

I'd be interested to know what the 300 c.i. I6 sounds like with duals. I've heard most v6s sound pretty bad with duals. Apparently, no matter what you do they sound like an import with a "fart cannon."

 

Actually, I live in SW Washington, we don't really have emissions or DEQ around here, or inspections, if I brought it into an exhaust shop, with just headers on and no exhaust, they might do it for me

 

Hedmen Headers are split, just like EFI manifolds, 3 of the exhaust ports go into 1 pipe, which makes for true duals

 

I didn't know that. Let us know what you decide.

 

Technically I've already decided, I gotta get the clutch replaced before I do any mods to it, cause it slips in 3rd gear

 

All you have to do is do a search on youtube for "6cyl split manifold. Lots of videos on it. It doesn't sound like a v8 that is for sure.

If it gets cold where you live, modifying it and putting the header on it may make the engine "cold natured" or balky when you start it cold. If you notice, the intake manifold is sitting right on the exhaust manifold. This lets heat from the exhaust warm the intake up so it runs better in cold weather. You will lose that feature with your header.

 

late reply but no it doesnt get that cold around here, and I barely even drive the truck in winter so it doesn't really matter, plus it might be a few months before I even get a custom exhaust for it.

 

I run the EFI manifolds and a factory Y pipe as thats the way I wanted to go as I can use all factory parts for the exh. system when needed.
I also use the factory intake / carb. & air filter.

I heat the intake floor with hot water before it enters the heater core, this helps keep the air / fuel in suspension. If to cold the fuel will drop out of the air and pool on the intake floor and cause issues.

The factory air filter has a hose that goes to the log manifold to get heat to heat the in coming air. This helps keep the carb from icing and helps in could running.
My flapper valve is still hooked up and should work, have not checked, but there is no way to hook the hose up from the filer to the manifold, I dont even have the hose on the filter.

The other thing you need to look at is the choke heating tube that runs from carb inlet through the exh. manifold then to the choke assy.
With out this the choke will not work right. The EFI manifolds do not have a way to run this line through the manifolds so you need to come up with something else to heat the choke.
I used copper line and ran it from carb. inlet like factory, wrapped it around the manifold a few times then up to the carb choke assy.
It seams to work and maybe too good as I think the choke pulls off to soon and, need to adjust it some more.

With my setup I have not had any issues driving in cold weather other than the choke adjustment.
You would need to do the same thing above with headers too.
Dave ----