Hey all,

So I finally got my truck on the road and it runs reliably now, thanks for the help gents! But there is still work to be done.

The passenger side manifold has a crack that leaks and stinks up the cabin pretty bad with the windows up, can't exactly keep them up when it is raining with this issue. I am wanting shorty headers as I can use the OEM y-pipe since I want to keep the cadillac converters , unless taking them off isn't a big deal and doesn't tick the computy off. I don't want long tubers since I have read that modification is needed, something I don't want to do.

Some summit racing brand shorty headers that are not bank breaking caught my eyes, are they any good? https://www.summitracing.com/parts/SUM-G9035 I am also needing some recommendations for the cat-back part too, it's become a ultra custom swiss cheese system. I am thinking of a dual side exit system. Any non-raspy mufflers y'all can recommend too? If I do take the cat's off would some actual mufflers help quiet it down compared to straight through ones? I want it to sound deep but nothing obscene, not looking for attention, mostly from peeved neighbors and I don't want severe droning while on the road either.

Truck is a bone stock '90 F-150 with the good 'ol 302.

 

I have no experience with those particular headers. I had JBA shorties and the welds where the pipes come together broke. The OBD-I / EEC-IV computer does not have an after cat oxygen sensor so it doesn’t know that the converter has been removed. Having said that there is no reason to not have one. The air injection system is plumbed into it so if the converter isn’t clogged or broken apart, I’d leave it alone. Doss your state have emissions testing? You will get a variety of options on mufflers. I have used Flowmaster in the past with no issues. Some say they couldn’t stand the drone and had it replaced shorty after having it installed. I have some generic turbo muffler on mine. It is whatever the exhaust shop put on there.

 

The Summit Racing branded shorty headers are just Pace Setter brand. I have had a set of them on the 351w in my '89 F350 for 10 years. I had a bunch of issues getting them to seal, and went through quite a few different kinds of bolts and gaskets trying to make it last. I finally tried Percy's "Seal-4-Good" aluminum gaskets and Percy's "Vibe Lock" header bolts. Have had zero issues for the last 8 years like that, and have used the same headers, bolts, and the same pair of gaskets on 3 different iterations of the motor in the truck with zero issue. I think Percy's was bought out by Taylor Cable, but they still make those gaskets and bolts.

The catalytic converters can be removed with no detriment to the way the truck runs. It will likely be an improvement, as the stock Y pipe and cats are pretty restrictive. If you have emissions testing, or even a visual inspection in your area, you're best to leave these in place.

I use Magnaflow mufflers on my trucks. Very mellow at idle so you won't wake the neighbors, but a very nice sound at wide open throttle. Not raspy and crackly like a glass pack, and not horrendous in the cab like a DroneMaster.

 

Thanks for the info so far!
I live in Georgia so I don't have emissions testing, that's for '97 - newer vehicles and visual inspection is non existent. So with the air injection system, if I took the cats off would it effect that system? I want to leave that system alone if it does.

I thought about some magnaflows, although I have looked a flowmasters flowfx series too.

 

I went the other way and bought another manifold-

and dang, it was pretty darned low quality.

That said, a few years and some thousands of miles later, it's still on there...

t

 

My truck has no cats and the previous owner bypassed the air injection system, since it is a hunk of power loss anyway. When the previous owner cut the cats out and welded shut the air injection tube at the exhaust.

 

How much power loss? I bet it is negligible.

 

According to a Ford authorized publication on Fox Mustangs I have, the pump eats 4-5 hp whenever engine is running.

That was new when the engines were tested for their advertised ratings. I'm sure age & wear increases that exponentially.

That adds up for a part that is only "on" 5 minuets or less each time the engine is cranked & run from cold.

 

That’s more than I would have thought. I figured maybe 1hp. It’s just pumping air into a tube. There shouldn’t be much resistance.

 

Sounds about right. Moves enough air to make sound enough to need a muffler.

Belt turning mass & having to make a right angle turn. All resistance & friction.