I just bought a 97 SS M6 from a used car dealer that has a number of bolt-ons and internal mods that I'm trying to take inventory of. The dealer didn't have anything from the previous owner about what was done and I have no way to contact them and find out what stock parts have been swapped out.

I've had two other LT1 cars before this so I'm familiar with the parts I can see - upgraded LCAs, panhard rod, aluminum driveshaft, CAI, pacesetter LTs, etc. just not what's inside the engine presently. The car definitely has a mild, streetable cam of some kind -- there's a distinct lope/choppiness to the idle and exhaust note that is not the result of mechanical trouble and the car makes a lot of power across the mid and top end -- the throttle response is very crisp and aggressive. There's lots more power on tap at all RPMs and pulls so much harder than the 97SS I had years ago that was stock except for shorty headers and CAI.

My question is if there is any way to identify generally or ballpark what sort of cam profile this has, and/or if anything else was done internally like manifold porting without disassembling the top end? Seems wasteful just to satisfy curiosity. I suspect it also has 1.6RRs, can those be visually distinguished from stockers when taking the valve covers off? I'm currently trying to line up a dyno appointment so I can get some baseline hp/tq numbers... I figured that would give me a better idea as to the extent of the mods and their benefit, I was just hoping there might be some other advice from folks who had more experience with the LT1 internals. Thanks in advance.

I'll put together a sig once I've completed my inventory of mods.

 

its going to be tough to identify what you have without pulling the motor apart. The bolt ons are much easier as they are visable to the eye.

 

Hey man i know how you fell i bought my car and could never find out what was modded until i took it apart i just hade an upgraded cam. An upgraded cam cold air kit and headers could have the car pulling like that through the rpms. Well anyway you could take a look at the throttle body usually if they port the intake manifold they would do the same to the throttle body. They came stock at 48mm so just check that and if its different then the manifold is probably ported as well. Also you should be able to take the valve covers off and just look at the rockers they came factory with stamped steel self guided rockers they might even have a label of some sort on them. **** mine are yellow i have the 1.5 roller rockers extruded version. Those are some things you could look at. I didnt think about the fact that if they have already made the header, cold air intake and other upgrades they probably reprogrammed the pcm. Id just start looking and in the end dont bother if shes got enough power for you because i just dont think its worth going down to the heads to find out if their modded or not unless the car isnt fast enough for you id just wait until you had all the parts you want to upgrade it with and then take a look as your taking it apart. Good luck bud

 

Does anyone here really feel like they have enough power? I'm certainly interested in possibly stroking it out to a 383 or maybe 396 but I would like to know at least vaguely what I had to build off of before I start investing in goods/services that I may already have and not find out about until - surprise! - the engine gets opened up. Either way, I'm pleased with the performance but the mod bug is biting me hard and I'm eager to feel my wallet hemorrhaging again and have cool packages arriving on my doorstep regularly!

Anyone have any experience with a dyno shop in Central Florida?

 

Put a dial indicator on top of a push rod and map the lift. Should give you a pretty good idea of the max lift. If you use a degree wheel you can figure out duration.

 

While the stock throttle body was 48mm, the stock intake manifold already has 52mm ports. It's possible to port the stock TB to 52mm.

http://www.injuneer.com/images/photo...takeTBDiam.JPG

 

Thank you guys for the information! I was reading that with many camshafts it's important to mate them with a differential gear ratio other than stock. Which got me wondering if I might also have 4.10s or similar out back. So I went and looked under the rear and there's a Summit differential cover, so someone had it open at some point. Think it's likely I have something other than 3.42s back there and is there any way to figure that out? I thought maybe if my speedometer was off but that can be tuned in the PCM I'm assuming. And on that note will a scanner/tuner be able to read a custom program and show me any usable information in my quest of discovery? I very much appreciate the input!

 

Turn the rear wheels one full turn. Count how many times the driveshaft turns. That is the rear axle ratio.

 

you could also get a carfax and find the names of people who owned it. maybe find the guy who modded it and look him up. just a suggestion though