longtubes on an l99

**mmd8x28** · 12-14-2009, 08:13 PM

Got a friend with an L99, and she wants longtubes on it...

Can an L99 get longtubes, and where?

**jaysz2893** · 12-14-2009, 08:17 PM

as far as i know the L99 is identical externally to the LT1, so I would think LT1 ones would fit.

edit:

L99 (4.3L)
A 4.3L (263in3) was a 305 with updated block architecture to be generation II and a reduced 3 inches (76 mm) stroke. It was designated the L99, and was introduced in 1994 for the Chevrolet Caprice. It was externally identical to the LT1, but the bore was 3.736 inches (94.9 mm) and the stroke to 3 inches (76 mm) giving it a displacement of 263 in3. The pistons used in the L99 were the same as the ones used in the Vortec 5000, but 5.94 inches (151 mm) connecting rods were used to compensate for the shorter stroke.
Like the LT1, it features sequential fuel injection, reverse cooling, and an optical ignition pickup. Output is 200 hp (150 kW) and 245 lb·ft (332 N·m). Due to its smaller displacement, it provides better fuel economy than the 5.7 L LT1, but at reduced horsepower & torque levels.

2nd edit,
I found some Lt headers for a 94 Impy SS:
http://www.summitracing.com/parts/HED-68294/

Maybe them?

**mmd8x28** · 12-14-2009, 08:24 PM

I didn't know if the exhaust holes were different size, like the intake manifold was (as I was thinking)..

**mmd8x28** · 12-14-2009, 08:29 PM

Looking at the pic, it doesn't look like it'd fit.. Something doesn't seem right about them..

Hard to see, but this is on mine: http://img.photobucket.com/albums/v3...agon/spark.jpg

If it's like mine, they should connect aiming down, not towards the rear..

EDIT: Oh, she needs EGR, but NOT the air pump, which is like me, as I'll be getting headers too, keeping EGR, but ditching the AIR.

**jaysz2893** · 12-14-2009, 08:37 PM

Longtubes connect under the car unlike the OEM Manifolds that connect up near the block. To finish it off she would need a dual exhaust set up (x or H pipe, mufflers, cats, and tailpipes to the rear)
If you want the headers to connect to the stock exhaust piping you need shorties, not Long Tubes.

**mmd8x28** · 12-14-2009, 08:43 PM

Oh ok.. We both have straight exhaust, no Y, H or X pipe.. Just each going their own way, so to say..

Then shorties it'll be.. But I do plan personally to get my cats removed, she's keeping them (because she may move to a state that has inspections).

**jaysz2893** · 12-14-2009, 08:47 PM

I made my cats removable. DE inspection mandates you at least have them. Some states you can not move thier location, let alone remove them. Most Shorties will have provisions for EGR/AIR. My LT's do not, but they do make them with the EGR/AIR fittings. I would have her check the local DMV for the rules with removing/relocating emissions control devices. Some state will not allow even the removal of the AIR.
BTW my car passes both visual and the sniffer in DE with the cat in the y pipe.

**mmd8x28** · 12-14-2009, 08:49 PM

Well from what I understand, GM said the AIR pump on B-Bodies can be removed, and if that's true, DMV can't say squat as far as I know.

**jaysz2893** · 12-14-2009, 09:20 PM

FWIW, GM does not care if you remove your Emissions stuff. Federal and State Laws mandate what you can and can not remove. (just ask anyone in California)

AIR is there to remove unburned gasses from a cold engine. Ones the engine gets hot enough it turns off. If she does remove it, it needs to be tuned out of the ECM.