LS1_MK2_Supra

I recently changed my mind on my Supra and am taking out the LS1 and swapping in an LS7. I picked up a bare block used, but can't seem to verify the casting number anywhere. It is 12571248AA and where it should say 7.0L on the block it does not, it has a P with an N below it. Any idea why it does not have 7.0L stapped anywhere? And why I pull up nothing with this part number? Thanks guys.

Jontall

It should have it on the rear bulkhead.

LS1_MK2_Supra

It does not, no displacement marking anywhere on it. Hence the thread.

rsz288

Any pics? Is that PN cast in or stamped/engraved in?

If it is an LS7 it may be an early 05 vintage casting. Does it have billet main caps with serial numbers? any serial number on the block......10 digits long generally engraved.

Gaz05

And like this... if you zoom in you can see the 7.0 on the front and the billet main caps with part numbers....

Gaz05

oops... Try again....other file too big, cant see the casting but you can see the main caps with the serial numbers in this pic.

LS1_MK2_Supra

Yes, there is a 10 digit serial number on the driver side rear side of the block, and it looks hand stamped because the numbers are not in a perfectly straight line. Also the main caps look billet. The P and N are cast into the front and there is just a P cast into the back where the displacement should be. No displacement casting anywhere. It looks from what you guys are saying that it is an early 05 casting.

Is it a good or bad thing to have the early 05 LS7 block compared to a newer one? The guy I bought it from claims he removed it because he was going big power and did not want a windowed block, although this does not look windowed to me. Are there flaws in the early 05 blocks of some sort?

nysbadmk8

LOL, I going to guess he ment "windowed" as in he was going BIG HP and he didnt want to throw a rod and "window" the block.

LS1_MK2_Supra

Windows in a block are an opening between the bores that allow the air the piston is displacing on it's way down into the next bore that has a piston creating a vaccum on it's way up. It creates less drag which = more power. Part of the reason I wanted the block is because it was suppose to be a windowed block.

AES Racing

iTrader: (6)

I don't think its an 05 block, the reason we found out the LS7 7.0 existed was a picture from cadillac pits in 2005, showing a block with 7.0 on it. CTSVR race cars were running LS7 blocks.

LS1_MK2_Supra

The main caps have hand engraved number for which cap they are 1-> 2-> 3-> 4-> 5-> is this normal? And looking from the bottom side of the block there is a threaded hole to the bottm right of each sleeve that I know is not there on LS1 blocks. Also another question I have is where do the knock sensors go on these motors? I am going to be running LS1 electronics and oiling.

nysbadmk8

I know, But from what you just told me is the person you bought the block from was going big hp in a LS application and didnt want the Ls7 block. I dont Know of any Ls style blocks that arent "windowed"

So I made the ASSumption that he might of been reffering to power levels since the LS7 block isnt exactly known for being a "stout" setup.

LS1_MK2_Supra

Oh, just the way you worded it I ASSumed that you were unaware of what windows were, lol. The internet loses a lot of expression to understand people sometimes.

nysbadmk8

It sure does, GL with the rest of the build.

LS3RX7

iTrader: (9)

All of the blocks I've seen with a AA letters after the part number and P or N on them are preproduction or test blocks. Hope that helps, have you confirmed the bores are 4.125" with the pressed in sleeves?