Ok, there have always been people that thought a mexican block was really no better than a stock block. However, there have been folks that accomplished feats that would be otherwise impossible on a stock block so I've always figured they had to be somewhat better. Example - Mark Harwell ran one in the KFC Outlaw car and virtually pegged a dynojet through the automatic with his Mexican block based motor (not filled or anything). This car did make a few passes down the track with that setup and according to Shane Hill, despite some serious tire shake/traction problems, it went into the 8's at over 170mph. It was later used in another very high hp application and the block never did break - it was just sold again. Another example is a member here (5.0 George) just went 8.90's on his Mexican block based setup. Yes, it's still a 2-bolt main block but what's the real story?
Even the fastest of the fastest one pass wonders on stock blocks are unable to hold a candle to this kind of performance. Well, I have a few stock blocks sitting around and a Mexican block as well so I decided to take some comparison pictures to start a GOOD tech thread for the real story on Mexican blocks (maybe something to eventually go in the Archives). Below are attached pics that show a few areas in comparison. Any other tech on the subject is welcome...

 

First, a Mexican Block should have the following label in the lifter valley - "Hecho En Mexico". If it isn't there, it isn't real.

 

Ok, now for a pic of the Mexican block (from the bottom in this case)

 

This is a stock block - notice the vast difference in main caps

 

This is the Mexican Block main webbing - the text in the pic is self-explanatory

 

In comparison, here is the same spot on the STOCK block

 

It seems most everything about this block is at least marginally beefier than a stock block. Here is a simple comparison of the sides. First, the Mexican block:

 

and now the Stock block

 

Here is the STOCK block looking through a cylinder into the main webbing towards the cap. I wish I had something as an indicator there just to show how deep of an area that is where there is no sort of metal.

 

same view on the Mexican block

 

Another view - Mexican block

 

and in comparison on the Stock block

 

And, the SAME location on another one of my Stock blocks

 

That was very informative. Many people like myself have wondered what the differences were, if any. It is very informative to see some actual comparison photos, rather than internet ghost stories.:tu:

 

good topic. Certainly does look beefier . They have this guy that lives an hour away from me that is selling one for $300. i was thinking about buying it, but does that sound a little overpriced?

 

I had one given to me, freshly machined .
I've seen them fetch a vast array of money but it really depends on what kind of shape it's in. Something to note is a Mexican block is NOT setup for a hydraulic roller cam. You will either need the retrofit link bar lifters if you wish to run that style cam or you will need to tap the lifter valley to accept the spider and use the stock style lifters and dogbones. This route will require the use of a reduced base circle cam though. Both routes will require you to measure for a new pushrod length.

edit: new pic I made of the comparison of mexican block cap vs stock block cap:

 

Good info.....:tu: :tu:

 

thats what i was going to do with my stock shortblock 351w with trw pistons. I was going to put the retrofit linkbar lifters(expensive) in it...then i traded it for a turbo!

 

on a mexican block there is also a large boss (hump) just over the oil pressure sending unit...easy to spot (maybe barry can snap a pic)...you can also read for hours how the mexican blocks have (and dont have) higher nickel content...some say yes, some say no...ill tell the truth, i dont know, so if someone could find any "official" truths, it would be nice to add to this thread...

 

Didnt someone on this forum or either the Hardcore50.com forum bring it to a place to test out the metal? im not sure but i remember someone doing that. I cant remember what the turnout was.