I just got done talking to the machine shop and they said that they wanted to have the pistons in hand to bore the block to the pistons. Makes sense to me. Question I have is what are the hypereutectic pistons? Are they better than the forged pistons that the machine shop recommended me getting? They also recommended me getting a dished piston since I will run turbos but I don't know if I should get the dished with a trough or the dished with four valve relief. I haven't even started looking at heads yet. I have a bit of saving to do before I can afford them.

I was told that I am going to have to go .60 over and that they were going to have to deck the block.

 

they are the middle of the road not cast and not forged(strongest)

 

imho if they have to go 60 over get a new block that is thin and can cause overheating problems

 

If you're running a power adder, you really need forged pistons. You should also consider matching rods and a better than stock crank. Expensive now, but cheaper in the long run.

Hypereutectic pistons are very good. Many builders say for the average street car they're better than forged because they don't grow as much. They're just not strong enough for a turbo.

The proper dish is important. You have to match the pistons to heads. So decide what kind of heads you'll use, then stick with that decision. At least stick with the chamber size.

 

I wouldn't put hypereutectics in any performance engine, especially one getting boost or nitrous. Get a set of Mahles, they may cost $700 but are much more technologically advanced, weigh less, have better ring packages, seal better, are more stable etc etc. The difference between a set of decent cast pistons and a set of really good forged pistons is night and day. Hypereutectics are cast btw, just with a higher silica content so they're stronger but also more brittle.

 

I was thinking about putting the H beam rods in and keeping the existing crank. That is after the machine shop takes a look at it first. I took it in with the block. Now after the block is bored and decked will the machine shop tell me what length rods I will need or how do i figure out what I need.

 

how much power are you expecting? cause h beams with a stock crank is overdoin it. i have my stock crank and rods with arp studs and nuts and im expecting at least 350hp at the crank. the stock rods will do that easily as long as you upgrade to arp hardware. and i have forged pistons cause i might be running a small shot of nitrous.

 

You really need to be looking at another block. .060" overbore is too much on a sbf. .040" is already pushing it. Considering your turbo, you should be looking at a sportsman block at the least, not something that needs to be bored .060 over.

Hypereutectics are great pistons for certain applications. I have them and they work great for me. They're much lighter than forged pistons, but stronger than cast pistons. They also reflect heat back into the combustion chamber very well, and don't swell with heat as much as forged pistons, reducing the likelihood of piston slap. That said, even mild detonation is enough to shatter a hypereutectic piston. With any kind of power adder, you need forged pistons to prevent this from happening.

 

Hypereutectics are not even CLOSE to being lighter than a good forged piston. A crappy forged slug, yeah, but a good forged piston is going to be VERY light(also expensive). For instance, a typical Mahle Powerpak forged piston for an American small block is 400 grams or less. Good forged pistons can be made much thinner due to dramatically higher strength to mass ratios. They also make forgings in many pistons using higher silica content as well, so they expand only slightly more than a cast piston. And yeah, hypers basically fracture under even small amounts of detonation. They work, but you get better performance and reliability from a GOOD forged piston if you're willing to pay more. Again, back to how much you're willing to spend and what you want.

No need for h-beams, especially on a street car. They don't move around(flex) as much as i-beams do, so their stiffness tends to be harder on bearings. The stock crankshaft is stronger than the stock block, and still reasonably light, so no need to change it unless it must be replaced or you're going with a stroker. A good set of i-beams are reasonably cheap(around $220 for a set of bushed Scats with ARP bolts) and offer good insurance.

I also would be hesitant to run a .060 302 for performance. Unless you have it checked for core shift, it's hard to know whether it will be ok or not.

 

"Good" forged pistons are particularly expensive:P I got my KB hypereutectics for half the price of a set of JE forged pistons. For my sub-400hp daily driver build, I'm happy with my choice