ZBRA

Going to be pulling the AIR tubes off the OEM LT1 manifolds. This is a race car and will not be street driven. I am needing some plugs to plug the holes in the exhaust manifolds where the AIR tubes went. I believe they are 22 or 24 mm, but I'm not sure. Anyone know of a source for some plugs that will fit?


**EDIT** The correct size for the plugs is M22 x 1.50

Aggravated4life

I used water pipe cast iron caps from Lowes to cap off the air system,but that was on an L98.If you have threaded inserts ontop of the exhaust manifold,you can possibly find the correct caps to plug them off.
The L98 air system doesnt screw off the manifolds,so I had to buy 2 caps to plug them up and leave the air pipes on there.Im not sure what the LT1 has,been a while.If you need plugs I bet some pipe plugs will seal them.

Also,Later on,with the L98 exhaust manifolds,I cut the air pipes off and got the holes welded shut for 5 bucks a side.Not sure if this helps but something to consider,even though welding is a permanent mod.

BlackC6LS3

M21 X 1.50...oil drain plug that can be bought from Napa for $6-8 each or I can throw them in with the cats

ZBRA

Thanks for the info. Think I'm going to put pipes in. I don't want the bulky cats, even if gutted.

I am completely gutting the car and making it track only. I will never be feesable to return it to stock or try to put it on the street again.

ZBRA

It has one large AIR pipe per manifold right in the middle. The hole in the manifold is threaded.

wro87

If you are converting to race. Look into long tube headers, I choose MELROSE long tube with no AIR, no EGR, no Cats, x-pipe you could go with 3" all the way out by mine are down to 21/2" to fit some mufflers. It will clean up the engine compartment and sure makes it easy to change plugs. wro87

ZBRA

Long tubes are definatelly coming. For now though, I'm spending all of the money on suspension and brakes.

ZBRA

You were close. They are M22 x 1.50.

Corvette Kid

They are 7/8" by 18 TPI. Good luck finding plugs that will actually fit them properly. They are a bastard size.

BlackC6LS3

Sorry! I couldn't remeber if it was 21 or 22 but I know Napa either has them or can get them for you

ZBRA

M22 x 1.50 oil drain plugs fit perfect. I installed them today. Auto Zone has them in stock behind the counter.

melrose

If all else fails go to a boneyard or a Corvette salvage yard and buy the factory AIR tubes, chop'em off and weld them shut.

SmokinLS1

I wouldnt go with melrose headers. Go to www.tpis.com and you can order egr block off plates for your lt1 manifolds instead of spending time and money going to a salvage yard. I recommend going with TPiS longtube headers. Ive seen and done both melrose and TPiS headers and Tpis is smoother flowing and easy install.

ZBRA

About 4 years ago, I installed a set of TPIS long tubes on my Admiral Blue '94 Corvette (LT1/A4). They fit great and were easy to install. I had one major complaint though. The quality was great EXCEPT, the O2 bung on the driver side header was welded on wrong. It was not properly aligned with the hole in the pipe that the nose of the O2 sensor pokes through. Once installed this was impossible to see, and I never though to look before I installed them. This destroyed the O2 sensor what I tried to install it and screwed up the threads in the bung. I had to remove the driver side header, cut off the o2 bung, and weld a new one on. This was also after I had had the headers Jet Hot coated, so it screwed up the coating in that area.

It was a minor qulaity control issue, but it created a huge headache and quadruplued installation time.

I'm leaning toward the EM headers when the time comes for this car.

johnanthonyhome

I hate to resurrect uch an old thread, but i've read so many conflicts. for my '94 the consensus seems to be 22x1.5 oil drain plugs? thank you in advance.