In NJ, emissions requirements on a reconstructed vehicle are based on the engine block. Unfortunately, that means a Honda or LS1-based solution has quite a high hurdle. I'm not even sure how a Dart, World, SVO, or GMPP block is treated.
For an SBF, engine blocks build in Mexico in the late 60's early 70's have thicker webs. I've heard all sorts of stories about these blocks: higher nickel content, 2-bolt Boss 302, etc. TTBOMK, there is no way to verify this. My guess is the strength will be similar to other 302 and SVO sportsman blocks: about 450-500hp.
Has anyone actually built one or more engines using this block? What is it really like? Can it accept 4-bolt mains? How thick are the cylinder walls? Does cryo treatment help (my guess is yes, although it is very expensive).
Any experience or information would be welcome.
Thanks,
David
Mexican Block?
Moderator: Team
Mexican blocks are stronger than stock blocks (80s and up) but not by much. There are stories that they've been seeing power numbers in the 600+ range but personally I wouldnt take it that far.
As for cryo treatment, its not that expensive and I am not sure if it really 'works'. There was a huge discussion about cryo on another forum but with no real answer as to whether it works or not.
My 2 cents.
-Dan
As for cryo treatment, its not that expensive and I am not sure if it really 'works'. There was a huge discussion about cryo on another forum but with no real answer as to whether it works or not.
My 2 cents.
-Dan
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machine shop tom
- Guru
- Posts: 2404
- Joined: Tue Dec 06, 2005 10:16 pm
- Location: N L Michigan
I used a '75 Mexican 302 for my 331 stroker.
There are a couple ways to spot a Mexican 302:
The un-used bosses on the front of the block and the Hecho en Mexico cast in the lifter valley.
As to strength.....the debate rages on with no definitive answer IMHO.
I do know that my block weighed in at 135# (give or take a lb) on my bathroom scale.
Also, the main caps are like the heavier 289HiPo.
There are a couple ways to spot a Mexican 302:
The un-used bosses on the front of the block and the Hecho en Mexico cast in the lifter valley.
As to strength.....the debate rages on with no definitive answer IMHO.
I do know that my block weighed in at 135# (give or take a lb) on my bathroom scale.
Also, the main caps are like the heavier 289HiPo.
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Mark Workman
- Pro
- Posts: 369
- Joined: Sat Oct 22, 2005 10:31 am
- Location: Missouri
After Ford stopped offering the 271hp option on the 289 in the late 60's, they sent the block tooling to Mexico, where it was used to cast beefier 302 blocks for quite a few years. These blocks have much stouter main caps(all 5) than standard blocks. In the mid '70's(FEA?), Ford started taking material out of the blocks to save $$. When the 5.0 Mustang came along and they started nudging the power higher, there were durability problems with those lightened blocks, and they actually put material back into them in '87(I think).
I've built about a dozen SBF's with the Mex block, and when freshened, there is much less fretting/metal transfer apparent at the block/main cap junction, but it is not completely absent, just not near as scary. They hold up pretty well in a drag race situation with 500+ BHP. Some guys have put a lot of NOS thru them, but to me, that stuff is too volatile to make any educated evaluations as to relative component strength, at least in the magnitudes in play here. I don't have any experience with them in a circle track situation. So far, no one has brought one back to me in a basket, like they sometimes do with street-driven late blocks, but the 50 0z-in spaghetti-crank has a lot to do with that.
I don't think you could make them into a 4-bolt configuration, but anything is possible, given enough money and time. If that is attempted, I would start with an early 302 block. I have not been able to document any increased section thickness of the webs, but while the blocks are a few pounds heavier than a regular 302 from the same vintage, the larger main caps are part of this. I think the modern Ford racing blocks are miles ahead of anything that ever came in a taxicab, and are a wise choice for any serious(even semi-serious) effort.
As far as a different alloy, I don't think so, I never heard anything regarding that. Unlike the GM boys, Ford guys don't seem to talk too much about different alloys. When I started porting, I worked on Fords for several years before I did an SBC, and I could feel the difference in the hardness(?) of the iron used right away. The SBC heads were much easier to grind. That experience, and the fact that Ford's cast iron cranks hold up pretty well even when leaned on, has led me to respect Ford's cast iron metallurgical skills, at least for an OEM.
My SBF block choices(others may not agree):
1. Aftermarket blocks
1a. SVO blocks
2. Mexican blocks
3. Early(pre-'75) blocks
4. '87 and later (for street hydraulic roller applications)
5.Anything else... roll it into the creek out back and find a better one, there are still too many good ones out there to use these anchors.
I've built about a dozen SBF's with the Mex block, and when freshened, there is much less fretting/metal transfer apparent at the block/main cap junction, but it is not completely absent, just not near as scary. They hold up pretty well in a drag race situation with 500+ BHP. Some guys have put a lot of NOS thru them, but to me, that stuff is too volatile to make any educated evaluations as to relative component strength, at least in the magnitudes in play here. I don't have any experience with them in a circle track situation. So far, no one has brought one back to me in a basket, like they sometimes do with street-driven late blocks, but the 50 0z-in spaghetti-crank has a lot to do with that.
I don't think you could make them into a 4-bolt configuration, but anything is possible, given enough money and time. If that is attempted, I would start with an early 302 block. I have not been able to document any increased section thickness of the webs, but while the blocks are a few pounds heavier than a regular 302 from the same vintage, the larger main caps are part of this. I think the modern Ford racing blocks are miles ahead of anything that ever came in a taxicab, and are a wise choice for any serious(even semi-serious) effort.
As far as a different alloy, I don't think so, I never heard anything regarding that. Unlike the GM boys, Ford guys don't seem to talk too much about different alloys. When I started porting, I worked on Fords for several years before I did an SBC, and I could feel the difference in the hardness(?) of the iron used right away. The SBC heads were much easier to grind. That experience, and the fact that Ford's cast iron cranks hold up pretty well even when leaned on, has led me to respect Ford's cast iron metallurgical skills, at least for an OEM.
My SBF block choices(others may not agree):
1. Aftermarket blocks
1a. SVO blocks
2. Mexican blocks
3. Early(pre-'75) blocks
4. '87 and later (for street hydraulic roller applications)
5.Anything else... roll it into the creek out back and find a better one, there are still too many good ones out there to use these anchors.
