Rods and hyperutectic

[DaemonForce]

It's hard to give an accurate idea of what I want to do but the main goal is to get my daily driver 83 Eagle back to being a daily driver. It's my main form of transportation and without it I become extremely irritable and permanently unemployable. My 258 engine blew up in June right after I got a nice machining job and I just want this garbage gone. My family has wrecked this engine in so many ways that I'm sick of seeing it and talking about it.

In its place I want to build and drop in a powerful rebored and fuel injected version that won't give me any more expensive migranes. I've already dropped $150 into tearing down a Renix block recently bored and crosshatched 0.060" over. I'm working on a high output 7120 head until I can get the money together for more parts. The problem is there aren't any reasonably priced parts for it, or rather the 258 specific parts like connecting rods. I'm unemployed 10 months out of the year so my money is pretty much gone ALL the time. I've been daydreaming about a nice Crower cam and other new parts but none of it matters if I can't get this thing built in the first place.

Any set of forged pistons run over my annual budget and because I tend to take short trips, cast will just annoy me worse than my grandpa's horrifying junky pickups. I want to put hyperutectic pistons in this engine but the information on Summit Racing doesn't make sense. I was looking at a set of Sealed Power pistons until this caught my eye. The dimensions look right but won't I need the 258 connecting rods in order to make this work? Who manufactures and sells them?

[IH 392]

Those are stock replacement pistons for the '96-'99 4.0, to use them in a stroker you'll need to use the short 258 rods.

[DaemonForce]

I figured I would need the shorter 258 connecting rods but I'm not sure which are proper. I see two castings: 318044 and the appealing 3237812. I have no information on either casting but they look the same to me other than the higher price of the first set. It would help if I had data like pin diameter and overall length. The hyper pistons I listed are for a 4.0L bored 0.060" over and they should work fine. Not sure what you guys would change about this so I'm just leaving this here to gather input.

[IH 392]

All of the 258 rods have the same dimensions, the "707" rods are the preferred ones, but they all will work, what's wrong with the ones in the 258 out of your Eagle?, I wouldn't go with a .060" over piston unless the block was that bad, I went with .020" over on my stroker, the block didn't even need that to clean it up!, go for the minimum over bore, you'll gain noting by pushing it to .060"

[DaemonForce]

The ones in my Eagle? I have no idea how to reuse connecting rods. I don't have the equipment for doing so and I just got rid of a set last week because I've had so much junk sitting in my back yard. The Renix block I tore apart has already been bored 0.060" so that's what's going to happen.

[IH 392]

The machine shop will press them off and back on, the old connecting rods are reused in about 99.998% of all rebuilt engines.

[DaemonForce]

The machine shop will press them off and back on, the old connecting rods are reused in about 99.998% of all rebuilt engines.

Well that would have been super helpful to know BEFORE throwing out the old rods from a 258 I tore apart last year. I guess this means my only choice is to tear into the blown up engine that's been sitting in my car for the past 4 months. I've been listening to an idiot mechanic that is too proud of his trade experience and he's forgotten everything so I have no idea why I continue to listen to him. I'm glad someone managed to tell me this about the connecting rods before I eventually scrap my last 258. This has been a nightmare.

[amcinstaller]

you can also possibly reuse that old crank, or depending on the shape of it just flog it off for a little money, help recoup some of this cost.

[DaemonForce]

you can also possibly reuse that old crank, or depending on the shape of it just flog it off for a little money, help recoup some of this cost.

I already have a 258 crank stored in the house after I ripped the last block apart. It's a bit rough but I think it might be in better shape than the one still sitting in my car's engine. It's been run out of oil enough times that SOMETHING related to the crank has definitely given up.

I live in an area where it's rather easy to find old AMCs that are ready to be scrapped. I'm often the first if not the only person that shows interest in them in the scrap yards and I could easily start a business of collecting, turning and reselling 232 and especially 258 crankshafts if I wanted. It seems to be a very popular demand and I just might do that when this fiasco is over.