360 magnum. 1 piston lower in cylinder??

JoePole1 said
He said that he would not trust the block of crank. I don't want to doubt his expertise but man this engine sure looks solid. I guess the previous owner could have been BSing me and yanked it before it let loose. It's almost completely apart so I guess a magnaflux of the crank and block would answer that. Correct?

AJ....good info on my LA360
Your assumptions are pretty good. Not sure about the 106* cam install. I believe it was straight up.
I am also not sure about the piston to deck height. I bought this motor rebuilt and have about 8000 miles on it. I tore it down when I got it but did not pay much attention to the pistons. They are definitely..030 and flat tops with no valve relief.
I also forgot to mention that i milled my heads .030. With that said 8.5 is what I estimated as well. Also my converter is actually 2500 and the tires barely spin.

I was really hoping to take advantage of the Magnum's rollers and 1.6 rockers.
Another option is to keep my La360 and use the EQs with the closed chambers upping my CR a bit and add cam but that's about the same scenario I have now.

As for the block, I did not think of that. It is possible that a hairline crack could have been formed if the rod was bent due to coolant getting into the cylinder and the cylinder hydro-locking...seen it before. A pressure test of the block is an alternative way to find that... And magnafluxing the crank is not what I would do.... check it for straightness and indexing first. If it is off, then replacing may be the easiest route... again, consult with your shop on that.

OK on the present LA360. With the flat top pistons and no eyebrows, I suspect they are about .100-.110" in the hole and are stock replacements. With the heads milled .030" and that piston and stock Felpro heads gaskets, then the SCR is around 8.3 so are about right. No way that the cranking pressures will be 170 psi unless the cam is all hosed up and waaaaay advanced, like 2 or 3 teeth (40-45 degrees)! And the lack of tire spin attests to that.... though the rear gear is not helping, the TC should compensate some for that tall gear if you had a true high compression engine.

Possible changes in order of increasing SCR:

Putting the EQ heads and thin .028" head gaskets on the LA360 will get the SCR up to 9.1. Better than 8.3 by quite a bit, but not quite maximal torque territory. With that tall rear gear, IMHO you need all the help you can get.
The LA 360 with H405CP pistons is 9.2 SCR; no better than what you have with just slapping the EQ heads on the present LA360, but lower than the Magnum setup below.
The Magnum block is .015" shorter, and the stock pistons taller, so that gets you up to 9.4 SCR with stock Magnum pistons and deck, the EQ heads, and the .028" thick head gasket.
Next step up is the LA360 with H116CP pistons (no re-balance should be needed with those), and EQ heads. That gets you up to 10.2 SCR with that thin head gasket, and 9.95 with a .039" head gasket. Since your LA bores are still fairly fresh, maybe you could do this with just a hone in the cylinders, with new pistons and rings. This looks to be the cheapest way to go to get around 10:1 SCR. Maybe $650-700 for new pistons & rings, shop work to put them on your rods, and a fresh gasket set.... plus all your time.
Finally, the Magnum with KB107's.... which are actually relatively cheap right now at $270 per set of 8. SCR is 10.35 with .051" thick head gaskets (standard Felpro's), and 10.7 with .039" thick head gaskets. Getting a tad high IMHO for the last one, but can be fixed. AND you get some quench effect to help fight detonation. You need to think hard about that high SCR.....it is getting into the range of serious tuning needed. Annnd, the piston + pin weight is higher than the stock Magnum by around 30 grams.... too much difference to not re-balance. So THEN you would need to:
- Add weight to the crank.... maybe another $250-350??
- Or, take weight off the pins and pistons.... possible (You need to be a bit careful to do this.)
- Or, put in SCAT I-beam rods and then take weight off the crank..... $300 for the rods, but relatively inexpensive to do the crank since the rods and pistons are well balanced from their factories and so don't need to be touched
- This last sub-option of new rods, rings, pistons, and crank-only balance is around $800 added cost above the straight Magnum with no changes IMHO.... all else being equal, and if your Magnum crank and block are good, etc.

While I would not kill for 1.6 rockers, they are an advantage. I became a believer with a 351 Cleveland; the stock 1.73 ratio made it sooo easy to get good lift with small duration. Better for low RPM torque. My son and I went with 1.6 shaft rockers on his 340 for that reason.