SN95 Block vs Fox Body Block

mo_dingo said:

I wasn't talking about you, I was talking about the mechanic who said the sn95 blocks were better than the fox blocks.

And my only point was that the blocks were similar, i.e. the heads on a 289 bolt up to a 95 5.0 and vice versa...
Scott

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I know,sorry man,I misread the post ,my mistake.

There is a TON of bad info in this thread...

First, there never, never, never was a 302 producted from the factory with forged rods. I'm not even speaking of the 5L HO motors, I mean anything that equates to 302 cubic inches.

Second, resource books are wrong - '93 5.0 motors did not have forged pistons. Hissin is right on once again...

Third, hypereutectic (which is the correct spelling by the way ) pistons have silicone contents in them to make them "softer". How silicone can ever make something harder is beyond me. Let someone throw both a forged piston and a hypereutectic piston at your head and you tell me which hurts less.

Fourth - forged pistons will do nothing for a bad tune-up besides put a bigger hole in your pocket.

Joe

Joes95GT said:

There is a TON of bad info in this thread...

First, there never, never, never was a 302 producted from the factory with forged rods. I'm not even speaking of the 5L HO motors, I mean anything that equates to 302 cubic inches.

Second, resource books are wrong - '93 5.0 motors did not have forged pistons. Hissin is right on once again...

Third, hypereutectic (which is the correct spelling by the way ) pistons have silicone contents in them to make them "softer". How silicone can ever make something harder is beyond me. Let someone throw both a forged piston and a hypereutectic piston at your head and you tell me which hurts less.

Fourth - forged pistons will do nothing for a bad tune-up besides put a bigger hole in your pocket.

Joe

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If there was never, a 302 with forged rods from the factory...then what were they made of?
I`ve read in the past that the 5.0L engines in 79-93 Mustangs came with forged steel connecting rods from the factory.

powdered metal?

I could be wrong, but I believe a cast piston will expand with heat much faster than a forged will. My understanding is, that Ford started to use cast pistons in the 302's for emissions reasons,.. im sure there may have been other factors.. but thats one that I am aware of.

I dont really think that piston weight was much of a concern to the engineers over at ford. Especially, given that the motor wasnt being taxed to the max, why would they step down to a .. forgive me. "weaker" piston. It would make more sense to stay with a forged piston due to strength,.. than have to deal with all the potential work orders.

Could it have been a cost issue?.. Im not sure. possibly. I mean, a couple bucks here and there saved on a car doesnt sound like a whole lot, but when you have a production run of around 100k units?.. it adds up.

However, the point has been made previously in this post. The hyper pistons are what you would call a weak piston,.. they are just less tollerant to detonation.
In my opinion, if your tune is safe, and you are looking for some pretty big power. (more than 500 HP) your pistons arent going to be the weakest link. The block is. Wich leads us all the way back to why this thread was started in the first place.

There is 0 difference between the fox body blocks, and the SN95 blocks. ok, maybe a couple of them have stray hairs from plant workers within them lol but seriously, there is nothing that makes them and better than each other.

Some people think that some of the older fox body blocks, commonly referred to as mexican blocks. (where they where created) have a slightly higher nickel content, and therefore are a bit stronger.. but, as far as I know, that hasnt really been verrified, and is still pretty much under speculation.

Personally, I wouldnt worry about much of the bottom end of a stock motor, maybe put some good rod bolts in it, but thats about it. If your talkin 450-500 horse, on a safe tune, and you dont beat the crap out of it on a daily bassis. you should be fine with stock stuff.

If you go much beyond 500 HP, then its time to start thinking about a better block.

Ive been in the game a while now, I dont claim to be 100% accurate on everything above, as I am by no means a Ford engineer. But, hopefully, this little book may have helped some people with a few questions lol

Until next time.

Actually, Mexican blocks were made in Mexico for Mexican use, the blocks in a fox body, or most anyother North American Ford were all made in the U.S.

Ford switched to Hypers because they produce less or no cold slap, and they can run tighter tolerances with them. They are also cheaper. The ONLY disadvantage to a Hyper piston is that they will withstand very little detonation before breaking. The only advantage to a factory forged piston in an FI or juiced engine is that they will take a little more before they break, but they WILL break.

Yes, early and Mexican blocks are built with a little more metal, but unless you like living dangerously and pushing things right to the edge, they offer no real advantage over a late roller block, you might get another 50 or so horsepower out of one before it too breaks.

As far as rods go, Windsor engines(289-351), have had factory forged rods since day one. They are nowhere near the quality of an aftermarket forged rod, but they are forged.

I hope that clears everything up!

larrendeuce said:

powdered metal?

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I believe the 4.6L engines, (except the supercharged 4.6L Cobra engines), use the powdered metal rods.

http://www.aa1car.com/library/2003/eb40354.htm

Everyone who wants to know about pistons needs to read the above link. If you don't understand a word, like hypereutectic vs. hypoeutectic then google it. There are a LOT of variables to a piston other than whether it's cast or forged.

My dad works at Mahle (maker of 33% of the pistons on the road), so if you have questions, I have answers.

SMOKEDYA said:

the only diffrence i've ever heard of was that the S/N's had hyperstethic pistons???? peace



john

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"Some people think that some of the older fox body blocks, commonly referred to as mexican blocks. (where they where created) have a slightly higher nickel content, and therefore are a bit stronger.. but, as far as I know, that hasnt really been verrified, and is still pretty much under speculation."

Sorry dude, I have to do this. notice that I said "some" of them.. and I also mentioned where the "some" where produced. I never said they where made for american stangs.. possibly my bad.. I was speaking of blocks in general, and how they are commonly reffered to.

"Ford switched to Hypers because they produce less or no cold slap"

Is that possibly because of ( My Post) "I could be wrong, but I believe a cast piston will expand with heat much faster than a forged will." I.E. it will seal the combustion chamber faster during warmup.

As far as pistons go, like I said before, forged or not, as long as the tune is solid, they are NOT the weak link in the motor.

As for the stock rods?.. I dunno,.. I have never heard of a stock rod breaking before the block does.


Im not trying to start a war, just doing my best to clarify, and stand my gound.



my $ .02

95GTAODE said:

Actually, Mexican blocks were made in Mexico for Mexican use, the blocks in a fox body, or most anyother North American Ford were all made in the U.S.

Ford switched to Hypers because they produce less or no cold slap, and they can run tighter tolerances with them. They are also cheaper. The ONLY disadvantage to a Hyper piston is that they will withstand very little detonation before breaking. The only advantage to a factory forged piston in an FI or juiced engine is that they will take a little more before they break, but they WILL break.

Yes, early and Mexican blocks are built with a little more metal, but unless you like living dangerously and pushing things right to the edge, they offer no real advantage over a late roller block, you might get another 50 or so horsepower out of one before it too breaks.

As far as rods go, Windsor engines(289-351), have had factory forged rods since day one. They are nowhere near the quality of an aftermarket forged rod, but they are forged.

I hope that clears everything up!

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Great thread! Sounds like:

#1 our blocks can handle up to 450-500HP. What breaks? The block itself? I have ARP rod bolts. Does this mean I can handle more HP?
#2 The connecting rods are forged.
#3 Ain't all that much difference between hyp vs forged pistons anyway to matter.
#4 Your mechanic is wrong.
#5 Related question..Is it true that the 4.6 blocks can handle TWICE HP that ours can handle??

Nosfurato, I think I just interpreted some of your post wrong.

Pokageek, The block will generally break first. They usually split down the lifter valley. It is possible to break pistons, rods, and the crank, but that is usually caused by another factor, like detonation or pistons hitting valves. Unfortunately, it's true that a stock Mod motor block can handle at least twice that of a 5.0.