1 7/8 Header to 3 inch review (Fit, sound and such).

getting a 3" over the axle is no fun.

it'll go, but there is maybe a 1/4" between the pipe & frame, and pipe & uca. You'd be wise to put aftermarket uca's on it. Gives a little more clearance over the stock style.

1 7/8 header is no problem depending on the k member. 2" fits, it starts getting tight though. There is very little gain going from 1 3/4 to 1 7/8 unless you are over 800hp n/a. There IS a gain, but it's minimal; like 2-5 hp and all up top. There is a gain going from 2 1/2 to 3" exhaust, and most of that gain is up top too. And there is certainly a gain in noise and heat. It's hard to find reasonably quiet 3" mufflers.

What about a 3” x-pipe reducing to 2.5” tailpipes? The reduction in temperature by the time the exhaust is that far back usually means a smaller pipe doesn’t necessarily decrease flow.

i used Stinger for the tailpipes. It is a 2 piece (per side) design which is a little easier to install. but it also opens up the possibility of leaks, so you may be wise to address that. I just used some band clamps and that took care of it. Biggest issue is clearance. You can't bend 3" as tight as you can bend 2 1/2" so things get really tight in certain areas. Fuel lines. Frame rails. UCA's. And fuel tank is also an issue with clearance. I wrapped the driver's side tail pipe with a little of that wrap stuff to keep it from melting the tank shield. On my 93, 4 cylinder, it has a single 3" on the driver's side and it's tight like that. Originally I didn't wrap the pipe and it melted right through the tank shield. Adjusted the position of the tailpipe, put a little wrap on it, and it's within 1.5" of the tank shield now. Also the UCA's hit the tail pipe in certain "spirited" driving situations (bushing flex, etc) so I had to bend the lip of the UCA's and even then they still hit if I am out in the mountain backroads on occasion. You can't really move the tail over anymore because the frame is already 1/2" or so away and if the tailpipe hits the frame, you get an aweful rattle (4 cylinder...), but if it rubs against the UCA a little, not so much. Under the car ain't no big deal, aside from a 3" muffler with enough volume to control sound properly is big, heavy, and with that, you get some radiant heat. I would probably address that with some sort of reflective heat shielding. Helps the a/c work better too (or makes it feel more comfortable in the cabin, faster). I have no cats but am going to put them on soon, high flow cats should fit ok. On the headers I currently have 1 3/4" Hookers on the one car, the other is a stock manifold (4 cyl). The hookers fit, well that's about all I can say. Multiple slip fit tubes on the pass side, plenty of leaks, messes up the HEGO readings. They'd be fine for a carb car or one that isn't a "driver". Just ordered a set of long tubes from RCI, be a month or two before I can get them in/on. Hope they are better than what's already on it although I'm pretty sure it'll also mean I'll have to build a new mid pipe which sucks. But it is, what it is.

If you can, use some tubular adjustable upper control arms, makes a lot more clearance around the tailpipe area where they go over the axle.

fuel lines, I just bent them a little to have enough clearance. Not an issue, but you'll want to watch that they don't kink when you adjust them.

If I had to do it again, I'd put 2 1/2" tails on the V8 car and probably the same on the 4 cyl (dual though). The 4 cyl is a turbo 2.3 out of an SVO, and any turbocharged engine will greatly improve response with reduction in post-turbocharger exhaust pressures; as did this one with a single 3". It was seat of the pants definite improvement, no question, on the very first start of the engine. Probably improved spool time by 300 rpm and I'd guess it makes an additional 20hp or so over the stock 2 1/4 to 2" system. But it still sounds like a 4 cylinder obviously, nothing you can do about that. Like a tractor.

On the GT (which is a 427" sbf), they all sound similar. The muffler you choose will dictate the 'tone" and volume. X pipe helps make it sound more raspy, more like a coyote or GM "LS", which I don't particularly care for. So I chose the H design which gives it more of a old-school Muscle car sound, sort of like the old 429" SCJ's, 427" GM's, etc. At some point, again I'm putting cats on it, and may end up going to a quieter muffler as the flowmasters, while they sound great, they are a little louder than I like. The more I age, the less I like the noise. I almost had a thought of designing an active exhaust for it. Quiet around town, open a valve when vacuum goes away to let it breathe when under heavy throttle. Hmm. Idea.

The T-Bird has a 351W with custom built 1-7/8" long tubes with 3-1/2" collectors, 3-1/2" X pipe, and 3" Flow Master tail pipes (two-piece units) and it all fits very well. No NVH as the rear end is planted with aftermarket control arms and I had a buddy that installs custom exhausts build the X and make "adjustments" to the Flow Master cat back. I know talk is cheap so here are the pics from the work and the entire system is jet hot coated:





With a 427 stroker and any kind of rpm (above 6,000 or so) you need to move up in size. For example, buddy had an 86 GT with 408 at 11.5:1 with Cooks 1-7/8" headers into a 3" X-Pipe and 3" tail pipes. Raced the car like that for a couple months and it was not performing like he thought it should and his engine builder said ditch the 3" and go to 4". 4" X-pipe with 4" spin tech mufflers and 4" turn downs and the car picked up 3 tenths in the 1/8 mile. For reference he shifted at 7,800. Big inch motors move a lot of air and need to get rid of it and small inch high rpm motors typically see gains with a larger diameter exhaust.

If you are dead set on tail pipes then 3" is as big as its going to get without some willingness to do a lot of custom work.