[Tommy R]

Hey you all,

I'm looking for information on 4th Gen F-bodies. Specifically, I'm interested in the diff options, gearing differences (rear end and tranny), 1LE vs. base model specs, and any other differences from model year to model year.

For example, I know the '93s are speed density, not mass air. Are there any differences there from a performance or maintenance standpoint? The '93s also had a slightly different T-56 tranny, as I understand it. Were '93 and '94 models not available with 3.42 rear gears? Would a 150 mph speedo indicate that the car has 3.42's? No governor? I remember my old roommate's '94 T/A didn't have the "GT" package and as a result had the 115mph speedo, governor, and maybe even 3.23 gears (instead of 3.42s).

I know in '96 they went OBD-II with dual cats. They're also rated at an insignificant 10 hp more than the '93-'95 models. Of course, in '98 the LS1 came out with much more power. However, the LT1s are obviously still very compeitive in F-Stock, despite the power deficit, iron block, and smaller front brakes. Any particular reason for this? Or are the right people just not running LS1's? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/unsure.gif)

So, needless to say, I'm intersted in LT1 vs. LS1 differences, too. But, I'll likely stay with the cheaper candidate, i.e. the LT1.

I should point out that I'd mainly be interested in F-Stock, so update/backdate concerns are of less importance. I'm not sure if/when I'd move to ESP.

Thanks in advance,
Tommy

[LT4Firehawk]

Suspension: Any differences among the years of LT1 cars? Obviously a 1LE isn't necessary to win. Any spring rate differences over the years? Sway bar/bushing differences?

All the same. Only suspension option was 1LE. Like you said, that's not really that big a deal, just get some Koni SAs or DAs and stick with stock springs.

Non-performance stuff: I know the Optispark can be an issue. And changing plugs/wires requires an act of Congress. But, what about the other "mundane" maintenance issues? T-56's and the rear ends seem to hold up well to anything, but drag slick launches. The LT1 sure seems plenty robust. What about steering racks, A/C compressors, window motors, electrical issues, fit-n-finish after 100k miles, etc.? I need to consider the whole package and potential repair costs and daily nuisances are a real consideration. I don't expect BMW interior quality, but just how bad does it get?

FWIW, I'm expecting the suitable candidate to have 100k+ miles. At that point I'm sure it'll be needing lots of maintenance, if not already done. Are bushings a PITA?

Window motors can be somewhat problematical, but that's just because of the design. They'll usually start slowing down long before they fail and give you plenty of warning.

Power steering pumps can also be prone to failure under heavy abuse, at least with roadcourse use. I'm not sure how true that is to autox, I'll let some of the others give feedback on dedicated autox PS failure.

Timing chain will probably be getting very weak by 100K miles. If it hasn't been done, plan on doing it immediately and going with an upgraded unit. While your in there is a good time to go ahead and replace the opti and waterpump. You should be able to go ahead and upgrade to a vented opti too, I know there's at least one place out there that sells a wiring harness adaptor to fit the late model opti to the early harness.

Really there shouldn't be a lot of issues if the car was well maintained. I sold my 95 at 97K miles and it was still in very good condition and fit/finish.

Diffs: Are all LT1's equipped with some sort of posi? Are they Auburns? I understand the LS1's came with Torsens, but even they have shown to be far from flawless. Do the Auburns wear and need replacement every few years? Suggestions here?

The LT1s (other than SLP cars) all came with Auburns. While they aren't as strong as the Torsen used in the SLP/LS1 cars, it is still a decent unit. I never replaced the stock one on my 95 and it had probably 200 quater mile passes, several autoxes, 10 track days, and 97K miles on it. It was still working like new when I got rid of it.