Considering getting a sporty convertible for easy driving/cruising. Noticed a 1999 Z28 auto with 70K miles advertized in the paper. What do I need to look for to determine type of engine and rear gear ratios (RPO codes)? What would have been stock?

What were the engine options and do they all require premium fuel?

Have never owned a Chevy but have often heard references to LS and LT engines but do not know the differences or pros and cons. From looking through the forum this morning looks like LS1 gets a lot of positive comments.

John

 

The only engine option for 98-02 Z28 Camaros was the LS1 5.7L; V6's were the 3800 Series II 3.8L My Z28 seemed to run fine on 91 octane (mid-grade around here...) without any problems, but I never put 87 regular in; gas is super high anyway, so an extra $1.50 a week isn't a huge deal for "cheap insurance". There are preventative measures built into the engine to keep it from harm if you do put 87 in, the knock produced will trigger a difference in timing to prevent the detonation if that occurs...

Between LS1 and LT1 engines, there are a good bit of differences...lots of people will have lots of information for you on that. The LS1 is a 346c.i. and the LT1 is a 350c.i. engine; LS1 creates about 20 more horsepower/torque, though the actual difference varies from year to year. This 1999 model you're looking at is one of the "lower-end" LS1's, since it has an LS1 manifold and not the LS6 like what came with 01s and 02s. Heads vary as well, but it all ends up generating about the same power, +/- 10hp; with all that said, LS1's get a bit better gas mileage as well; capable of 30+ on the highway when driven conservatively

For gears, your car will probably have a 2.73:1 ratio, which you can see by your RPO code as mentioned. GU6 is a 3.42:1 ratio, so I'd assume GU5 would be 3.23's, and GU4 would be 2.73s, but that's just a guess. Apparently that sort of thing is not written in stone, since my V6 car had GU6 on it, and supposedly all the non-Y87 cars (which mine was not) came with 2.73's...you can do a search on here for something like "gear ratios" and maybe come up with a chart showing the RPO codes...

I can't really think of any cons for the LS1... there is so much potential for them, and a huge aftermarket following. It really seems to be a perfect engine for any performance oriented application short of dragsters

I was going to buy an auto Z28 at one time, but it had a leaking differential and rear main seal; and I've heard those are two weakish points in our cars; I'd recommend taking it to a good mechanic to get their opinion on any repairs and to do an overall check on all the systems to see if it was maintained properly. If you've got more questions there's a lot of knowledgeable people on the board so post em up!

 

Pinion seals almost always leak from the factory even. If you have a leaker, just make sure you fill the fluid. Also, check the rotors. Stockers on my Firehawk were warped at 15,000.

-Geoff

 

LT1's sound better.

 

This is true; but that isn't a con of LS1's; they sound good too!!