I have a 1993 LT1 engine that I was planing on changing out the bearings since the engine is out and torn down even though it only has 35,000 mile on it. I have not taken the old berings out yet but looking at the front main bearing (the one that can be seen behind the timming gear) it looks like these engine use solid alulminum bearings.
So would it be better to use the tri metal chevete 77s I have or would aluminum bearings be better?

 

These links have good bearing info.

http://engineparts.com/motorhead/tec.../brgselec.html
http://www.federal-mogul.com/cda/con...3_6752,00.html

AFAIK the main advantge of aluminum bearings is corrosion resistance, which is not an issue in a high performance rebuild as they will need to replaced long before corrosion becomes an issue. My advice is to stick with a high quality traditional tri-metal bearing for a hi-po motor.

Rich Krause

 

Bearings for cars all are steel with coatings. Most of the thickness is the steel. Rich's links are excellent. Study them.

35,000 isn't a lot of miles for a bearing change, but if it's apart, consider it. You might want to have the crank polished if you put in new bearings. Depending on how modified the engine is and how hard you use it, the premium bearings are probably a good idea. If it's a stocker and won't be modified, bi-metal or standard bearings should be fine. I'm at 95,000 on my Impala LT1 with no need for any replacement yet. It sees WOT and max rpm shifts very regularly...except in the snow.

 

I finaly got the engine torn down completely, the original bearings were bi metal steel back and aluminum aloy overlay.
the dana web site http://www.engineparts.com/ that I found was very informitive and convinced me that the tri metal bering would be the best bearing to use for this street engine. \
I'll have to check out the other two sites above to.
I noticed the cam bearings were the most worn probly because of there slow turning speed, high loads, and soft bearing material used.
this engine was sitting for over 5 years after a front end colision and there is alot of antifreeze gunk to clean out of the block..... good thing its all water soluble, but that stuf sure makes a mess.