gmv8power

Good morning gents, this is going to be a long one. I am faced with the following conundrum. I have a 1999 Camaro SS M6 hardtop, my plans for the car is to make into autocross vehicle. Here is my question; with the car having 195k on the clock should I attempt to touch the bottom end during the rebuild I have started. If so what how far should I got with the bottom end, there will no nitrous nor boost ran through the car at any point. It’s an all motor application. Car runs great no excessive oil consumption; I am the second owner of the vehicle. Car was maintained meticulously and is in exceptional shape. As for the top end I plan on sending my stock heads to AI and letting them do their magic. Trying to keep the engine a budget build simply because I am putting a lot of money in the suspension and safety provisions. If any of you guys did anything similar please feel free to chime in. Trying to get this done right the first time. Thanks for your time

td1168

iTrader: (2)

Your question is a wide open one. The stock bottom end will live all day long under 6500 rpm's. the question of whether to rebuild the bottom end can only be answered by tear down and visual inspection. At this point with 195k miles you might as well, at the very least, put new bearings and rings in it while you're in there. If you are asking whether to just leave the bottom end alone and put a top end on, thats a crap shoot. Would I do it, NO! With that many miles, I don't care how good it sounds or the amount of oil it consumes, your are planning on wingin this motor if you are running autocross. Just rebuild it. This will alleviate the guesswork.

wildcamaro

iTrader: (15)

I have a 200k mile bottom end motor and I left the bottom end alone as it also wasn't having any oil consumption problems...if your trying to stay on a budget I would leave the bottom end alone, if it was taken care of then you should be fine...

Obviously it is better to do a complete rebuild but from my LS experience these bottom ends are pretty stout and when maintained properly can take a lot of miles...since auto toss doesn't need sustained high rpm is in your favor as well...

gmv8power

That’s what I was leaning towards. Since I am going to have the heads off why not freshen up the bottom end. I have been out of the LS1 game for a while now, what would brand would you recommend? As for the heads , do you guys think that the stock heads with AI full port work be enough? The heads are the 853’s, I understand that they are not the best flowing head out there. However, won’t they help with having a more usable power band and save me some money against a 243 head?

wildcamaro

iTrader: (15)

If you are going to get porting I would spend like $100 and get a set of 241 castings off the parts forum on here and have those ported, although I'm sure porting the 853 would still be a huge performance gain head flow wise, even mill them a little to get some compression...a cnc ported 241 will be the same as a cnc ported 243, only benefit of the 243 then is the smaller chambers, but you can mill 241 to get the same effect ..

On bearings you can't go wrong with good old clevite 77, Texas speed and scroggins dickey sell some pretty complete rebuild kits with all the gaskets, bolts, bearings etc. you always save money buying that stuff in packages rather than buying one at a time.