[Steve91T]

So I've got a 97 SS that now looks like a mismatched LS1 SS. I'm running a craigslist LT1 that's bone stock, down to the mani's and Y pipe. The engine sat for years before I got it. I did a dry compression and leak down test and my numbers were all over the place. I took the chance that it just needed to be run. Long story short, it took a while but it started to run pretty good. So now I've done 3 track days and it and it blew me away. I fully expected to go home with no less than half of the Pistons I started the day with. Not only did it not miss a beat, it used at most 1/2 quart of oil, no smoke, and seemed happy as hell all day long.

So my plan was for an LS1 swap later this year. But now I'm thinking this engine might be healthier than I thought. TT3 rules require me to have around 350 rwhp for my comp weight (3400 lbs). I can knock 100 lbs off the nose by going to an LS1 and light flywheel and clutch. The problem I have is my LT1 isn't worth anything. $500? Maybe? I figure the LS1 swap will cost me at least $3k. But LT's, cam and tune will be about $1500. I figure both should get me close enough to 350 rwhp.

Right now I'm way down on power, so I have to do something. I really want an LS1, but is it worth an extra $1500? At the same time I'm afraid I'm going to buy headers and a cam and the next day it's going to blow up. What would you guys do?

[Casey_SS]

Problem with the LS1 swap on these cars is all the little stuff that also has to be changed, i.e. trans, clutch hydraulics, pedals, wiring, etc. But I'd imagine you know plenty about that already. If you're content to run it as-is until something "bad" happens and then decide what to do next, that wouldn't be the worst way to go by far but if your goals include running a trouble-free season, multiple seasons, points championships, etc. then read on...

With the motor sitting for a long time, the main concern is moisture damage, i.e. rust in undesirable places, pitting of the bearings and so forth. If any of that is suspect AND you'd rather deal with it now vs. "wait and see", here's what I would do:
1. Pull the motor before it develops an issue and if you have a good local shop you trust, rebuild the short block with good bearings setup on the loose side (.0025ish on mains & rods). Have it internally balanced, add an ATI damper and neutral balanced aluminum flywheel - have it balanced with the pressure plate attached. If you don't have a good local shop, then order a crate short block from a reputable builder. They're not much more expensive and shipping is on par with a set of brake pads. You don't need expensive forged pistons or fancy cranks but a budget brand (Scat?) forged I-beam rod with ARP bolts would be a reasonable upgrade for longevity.
2. Send your heads to AI, LE, or whoever is still doing these. Better option is to get a set of AFRs and run a smaller cam for more torque while still making the number you want on a conservative tune. Personally, I'd shoot for 12.0-12.2 AFR with 30-32 degrees of timing. If you can make the number on that, you should have plenty of safety margin for hot days, sub-par gas, other stuff going wrong, etc. If you're willing to spend a few hours with Google, you'll find you can swap to an OBD1 PCM very cheap and tune it yourself with free versions of Tunercats and Datamaster. You'll end up spending the difference on a wideband and dyno time but you'll be in a better position for the long run.
3. Use an MSD opti cap & rotor to avoid the plastic "weld" on the rotor letting go at high rpm. Put red loctite on the rotor screws.
4. Use a Canton road race oil pan with a stock pressure Melling pump. High volume pumps put more oil in the heads and it can't drain back fast enough without machine work to enlarge the drain back holes.
5. Save headers for a future upgrade. They're expensive to start with and you'll need a welder to fab the rest of the exhaust to actually fit without burning stuff or getting crunched every time you hop a curb or back off the trailer.

Opinions will vary and it's easy to sit here and spend your money but honestly, if I were starting over with a 97 SS as you described and I wanted to race it for the next 3-5 years, this is exactly what I'd do. Hope this helps...