coanan

I have a 99 FRC with no mods to motor. I have a chance to get a set of KooKs 1 3/4 LTs at a very low price and was wondering if I should go with them or save for LGs or ARH, money is a factor for me. The LS6 intake maniflod will also be apart of the change now. For the future; I'm looking for mid range torque not high-end HP. I'm undecided on a Cam and heads. I really don't want to get into the engine, it has 53000 on it, not looking for a dragster "Street use only"

Bill Curlee

If your getting them at a really good price, Hell dont pass them up! If money wast an object, ARH would be my choice. Your only talking a few hp/tq numbers especially on a stock engine. Are they on the car yet?

BC

madmatt9471

Get'em if you can and when you do this too:

Get the Hi-Flow Cats and thw X-Pipe that goes from the 3" to the 2 1/2" pipes !

This will keep your TQ up and a nice flow - You will not loose anything only gain with this set-up!

Thanks,Matt

leaftye

The tunes will be great. I wish I could tell you how much you'd gain, but my Kooks w/midpipe & cats have been sitting in the garage for over a year....eventually I'll get them installed!

Bluefire

I just ordered AR Headers from my tuner. I don't know if they are 1-3/4" or 1-7/8" primaries. What is the correct size and why.

Thanks,

Randy

LoneStarFRC

You won't be disappointed. Be advised though that the Kooks will require raising the engine a tad for the install.

I see you're in Florida but don't know where. There are several folks in Fla that handle the install for you if you don't want to tackle this yourself.

BTW, make sure the headers have the round ports to match your heads and are compatible. The later LS1/LS6 heads have "D" shaped ports. Also, I would recommend either re-using your exhaust manifold gaskets (if they are in good shape) or get some new OEM GM ones. they do an excellent job.
HTH,
Robert

Z06Electron

LS1 241 cast heads never had D shaped exhaust ports. They have the same oval exhaust ports as early 853 cast heads. The LS6 243 cast heads are the only ones with D shaped ports other than 317 cast LQ4/LQ9 truck heads. I know because I sold a set off of a 2004 crate engine and they were oval. Headers are all round, and compatible. The reason you see different year ranges offered is because 97-mid00 used different dipsticks and AIR tubes than 01+. The LG's have 97-00 01-03 and 04 available because the O2 sensor connectors changed in 04 to incorporate the same plugs on the front and rear, whereas older models had different connectors from front to rear. Also it's not advisable to reuse your stock manifold gaskets as they will not seal your headers very well. You are going to want to order a set of aftermarket 2002 trans am metal gaskets. The trans am gaskets unlike the corvette were rounded and fit headers like a glove. Hope this will help you out. If the headers are for a 97-00 and you have an 01+ you will need to replace the dipstick and bend replace the AIR tube. If they are made for 01+ and you have a 97-00 then you will need to do the same, either way they will work on your car, guaranteed.

LoneStarFRC

True enough. It's just that he never said anything about the set he was thinking about buying.

Z06Electron

His oval exhaust ports have no effect on the header design. The only difference on headers is where the AIR tube is welded. The 97-00 Headers have it welded on the far back primary, the 01+ have it welded to the second to last primary. Most headers are manufactured with the Dipstick tube bracket required on 97-00 cars, even though 01+ dipsticks mount to the heads. This cuts down manufacturing costs and allows for interchangeability between years. Should someone buy the wrong set of headers down the line. The heads have no play in the headers shape as they are all round and mount the same regardless of heads being used.

coanan

The headers are from a 99 and I have a 99, so they should bolt up. The headers I'm looking at do not come with cats or X-pipe. How much would that be or can I just use the stock cats and H-pipe?

Z06Electron

You'll want to invest in a complete setup or buy these and buy cats and x from kooks. The exhaust work $$$ will eat up the difference in cost, so it's not ideal to use your stock stuff. What are you paying for these if you don't mind me asking?

LoneStarFRC

If he were buying a set of headers that were made for a say, Z06 with D shaped heads and not the round, wouldn't that change things?

LoneStarFRC

Z28TOZO6

1-3/4 is normal for low HP or "stock" Cars. If they are too big it screws with your back pressure and will cost you HP.

LoneStarFRC

Don't tell that to Lou over at LG.

Z06Electron

Well Lou is only running a Big cube 600+ Hp Car after all.

LoneStarFRC

Is he running his LG Pros with 1 3/4"s?

Z06Electron

I don't know what he's running on his C6 Z now, but I know he was running LG Pros(a version of them anyway) on his C5. He Races what he sells.

Z06Electron

Just checked, they only sell 1.75" even for C6 Z06, so I'd say yes he's probably running the same size.

LoneStarFRC

Since he only offers his LG Pros in 1 3/4", that kinda blows some holes in any "hard-and-fast" rule about 1 3/4" only being for lower Hp cars and serious Hp cars have to use 1 7/8".