What would you look for when buying a used block? What are the most important things to catch before purchasing it? What are the good and bad about using a Automatic LS Bottom? Is there any different from a manual block and auto block?
Is a auto block on a manual tranny a bolt on thing or do you have to modified it to make it work? Well i hope you guys could help explain it to me. I would like to pick up a exta auto ls block for dirt cheap. THanks.

 

auto and manual blocks are identical. the only differences are the auto blocks have a flex plate instead of a flywheel.

just check to make sure there arent any major cracks in the block, the sleeves arent all rusted to hell unless you plan to resleeve. also check if the main journals are still in good shape and all main caps are included.

 

Most used blocks, even heavily used blocks, are repairable at a certain cost. A refurbished used block is just as good or better than a new block. Just gotta make sure all journals are in-line, deck surface is flat (straight-edge and feeler gauge), check for heavy corrosion around water jackets, make sure cylinders not cracked (LIGHT rust is okay, especially since you'll probably end up over-boring).

Checking for cracks is kinda pointless to do by eye. Even though you might not SEE any, there could be some extra-tiny cracks. You can use a magnaflux magnetic crack inspection or dye penetrant to check for tiny cracks. Even the smallest invisible crack can cause a total loss of compression.

If the centerline of the crankcase is not warped too terribly a line bore can be performed to make them true again.

Machinists can fix just about anything (within reason) and it doesn't cost that much.

 

the Auto and Manual is identical as people say, all you have to do is get a flywheel and remove the flex plate (make sure you use the manual flywheel bolts, the auto wont work, their too short)

i prefer getting autos because in theory, they have been abused less because the automatic transmissions shift at lower RPM but thats only IMO,

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civicstar &raquo;</TD></TR><TR><TD CLASS="quote">
i prefer getting autos because in theory, they have been abused less because the automatic transmissions shift at lower RPM but thats only IMO,</TD></TR></TABLE>

that is a great point..

 

Thanks everyone for your replies.