Is a Mexican Block Worth the Trouble?

[randy wilson]

I don't know about filling a Ford block, but I've filled three GM 283, and 327, and 350 blocks in my life. I would NEVER fill a block. Every time we've done it, when you get ready to re-hone, the chatter from the stones going down in an oblong bore, is deafening. They NEVER stay round. On the other hand, when not using filler, the block was WAY straighter. And yes, we use a plate.

[BillK]

Originally Posted by randy wilson

I don't know about filling a Ford block, but I've filled three GM 283, and 327, and 350 blocks in my life. I would NEVER fill a block. Every time we've done it, when you get ready to re-hone, the chatter from the stones going down in an oblong bore, is deafening. They NEVER stay round. On the other hand, when not using filler, the block was WAY straighter. And yes, we use a plate.

Randy,
Curious as to what you filled the block with ? I had the same experience years ago with a block I did for a customer that he had filled. He used one brand of filler that I had never used and his block did move around a lot on the first freshen-up and a little bit the second time.

I have always used Hard Block and have never had it move around ?

[Paul Precht]

When filling I use Halco Machine Grout and leave the block sit for at least a month with the mains and both heads torqued, then I bore and hone. If you're in a hurry it becomes a compromise situation.

[FireSale]

Got an email from this fella and it's still for sale. He says it was last bored 50 over. The NHRA limit is 80 over, so is this block weakened if it's a total of 60 over stock?

Dale

[HR9121]

I ran a 302 Mexican block in my hr/sst car a couple years ago, it was 60 over and not filled. Made over 400 passes with never a problem and it turned 77-7800 when running 1/4 mile.

[Pat Cook]

Is the Ford Motorsport block legal?

Part number M6010BOSS302K

[FireSale]

Originally Posted by Pat Cook

Is the Ford Motorsport block legal?

Part number M6010BOSS302K

That's the interesting part. it's not a BOSS block. It's a 302 replacement block made in Mexico and used by Ford for a lot of warranty stuff. It's a little stronger that the stock 302 because it's a bit thicker and has beefier mains, they are still 2 bolt, though. Bore, stroke and deck height are stock equivalent 302. Just stronger.

It's still for sale and has only been bored out the 50 over. I'm going to look at it next week. It's a little more sane for me as a hobby racer on my first build.

And, yes, the 6010 is legal in SS.

Dale

[Dyno]

If it is .050 over already, save your money and try and find a standard bore block. He is selling it for a reason, usually not good.

[SStockDart]

I read up on Mexican Blocks before using one in my street rod...(55 F100)....please understand that this engine is intended to "sound good" and I don't care how fast it it.....it is a 302.....I understand that the Mexican block is better because it has more nickel (SP) content....I don't know why that is better, it is just what I was told.....I never run the streetrod over 6,000 so this might not be a good example...no sleeves, no light weight parts....."It sounds really fast........but it isn't".....LOL (that is what street rods are supposed to do)

[71mavlouisville]

Dale, there is a B-50 “sportsman” block that Ford was making that was a “new” casting of the “mexican” block. I put about 100 passes on this type of block turning 9500 rpm around 580 hp without block fill and without a stud girdle. Just make sure and have quality machine work done and use ARP studs throughout. As soon as I could afford it I went to the “Boss Block”. There is a WORLD of difference between these blocks. The boss block is around 20 pounds heavier than the B-50 block I was using. There is a TON more material in cylinder wall, lifter bore area, cam tunnel, deck and mains. = more HP

The machining cost is the same on a production block and boss block. The Boss block is REALLY “cheap” at $1800.00 Figure a Used block, machine work and then if you are crazy enough to try and use hard block, dealing with the overheating from the block filling, ring seal etc, believe me go with the best parts first. You are going to end up buying it in the future anyway.

Whatever you do, do not bore over 0.040” in a production block, test the wall thickness with US, the production blocks are super thin.

Happy building.