I took the plunge and bought the "book", you know the one.

Also, I just started tearing down a 4.6 from a 2001 p38. I have torn down 3 other 4.6 motors in the last few months, form 03 and 04 discoveries, but never saw the infamous paint daub grading on the blocks.

I'm guessing that by 03/04 the only motors LR was building were 4.6 so no need to add the paint daub, but I will go back and inspect the other blocks closely to confirm.

Anyways, here is the 4.6 block from the 01, and the pages explaining the grading from the "book". Interesting to note that they say some motors were not built by LR for warranty replacements etc and these did not respect the grading system. Also the book basically says if you are building a motor to do so with anything less than a red quality 4.6 block is a waste of time.

Read it and weep, or rejoice depending on the block you used.

 

Hope you found it (the book) cheaper than those last week.

ahh... a red block and a clean one at that. I've never been able to see the paint in the valley, only back in the webbing..... and none have been red. haha!

 

I didn't pay the $1500, but I will say it cost more than the last parts car I bought!

What colors paint have you found?

 

dang...on the price of those books. I swear those were right at $200 not even a year ago.

blue and white I think.

and blue is the worst if I remember correctly.

and I have a 4.6 block now with none to be found like you mentioned.

 

I'm pretty sure by 03/04 they didn't care. Maybe that's why so many D2 4.6 motors are failing.

 

Blue is the worst, yellow better, red best. White means too many pints at lunch for the worker doing the grading.

 

My understanding is that the warranty blocks produced after 2004 were made by an aftermarket vendor. LR was required to have warranty parts available so they sold the tooling to an aftermarket company who refreshed the molds and started turning out much better blocks. I have one of those in my truck and when I pulled the oil sump I could clearly see all of the liners were pressed firmly down to the registers at the base of the bores which clearly isn't always the case with the factory blocks. No way to determine the thickness of the block by the cylinders, though.


It seems that the later 4.0 and 4.6 engine runs were something that LR cared very little about so they probably gave up on grading them. If you are building a motor and have the chance to get a 4.6 block from a P38, that's the only way to go.

 

I guess the paint dobs in the back of the block are for grading?
I've looked there in the valley to see if any matched and no luck. I've only fooled with mostly 4.6 though so, the paint I've seen may be for something else.
I do have a 4.0 and it has blue and on the back of the block.
Did they mark them back there also?

 

Good info, thanks for sharing!

 

Yeah haha! or maybe the white was yellow and I had too many pints.
or maybe the white was for something else?.