Best pistons right now For a 425 toro block. 20 over. Ka heads

shop says he likes egge. Any feedback?

 

You are probably not going to have much choice unless you order something custom made. Egge is fine for a stock engine. I did a 425 with their pistons about 2 years ago and it is fine.

 

Ya no boost or nitrous. Just freshen up and bigger cam. Looks like egge is nearly 700 for a set. Dss has forged set for similar price. Wondering why I shouldn’t go w DSS?

 

I put Egges in my G-block. Couldn't find anything else suitable at the time. They've been fine.

No experience with DSS.

 

The Egge cast pistons are likely short on compression height, which means lower CR than expected, so keep that in mind when choosing a cam.

 

If you go .030 over you can use the Mahle 350 4.155 pistons (.030 over stock 4.125 bore) This will give you floating pins and require the rods be honed for the .984 pin.
Running these pistons/pins drops a total of 4.5 lbs over the stock 425 pistons.

 

Those are lighter, are the correct height, and use a better ring design. All result in greater engine efficiency.

 

Egge are CAST pistons. "nearly $700 for a set" is over priced.

 

If it were me, I would go with this formula..thats a lot of weight savings on a reciprocating assembly. Especially if Egge are 700 for cast pistons..I used wiseco forged and h beam rods on my 455.. the weight savings was like this, incredibly lighter. Much easier on the other parts..

 

^^^^^.
And I offer the Mahle for just $75 more than the Egge’s, at $775.00 shipped, with rings.

 

Yeah, I was going to say the same thing. For the price of Egge's cast pistons you can get forged ones.

 

Ok so Andy, Marc and Fun71 are all talking about the same product? Just need the stock rod machined for a larger pin? Seems like no brainer

 

The Olds 350 pistons use the same pin diameter and same compression height as the 425 pistons. There's no machining needed on the rods.

 

Joe looks like the MAHLE product uses a larger pin .984. Wonder why. I see factory 350 and 425 share same same pin size .980.

 

Mark can answer that question for you.

 

Just want to make a couple of real world observations/comments.

The Egge pistons I got were very very close to the weight of the factory pistons so no balancing was required.

V8al mentioned floating pins. Only if you bush the original rods. Another $200 expense to think about.

The Mahle pistons are very nice but a lot of guys have a real problem with the new very thin piston rings. The oil rings can be a beeech to get on and you pretty much have to use a one piece tapered ring compressor. Another $50 expense.

The DSS pistons use a more traditional 1/16 1/16 3/16 ring pack which is much better than the original but a lot easier to work with. Plus they use a .980 pin so you dont have to mess with the rods unless you want to full float them.

You probably already know this but make sure you get the correct camshaft. 425's could be either 45 or 39 degree bank angle.

Just thinking out loud

 

Thank you Bill. That’s exactly the summary I was looking for.. Toro motor 39

 

Unless the pistons were exactly the same weight as the stockers, it should be balanced anyway.
And if someone can’t get this thin ring pack compressed in the bore, then they shouldn’t be assembling an engine. You can almost compress the rings with your fingers.
In addition, the 1/16 ring on the DSS piston is .016 thinner than the Egge, but has just about the same radial depth. The Mahle ring is .022 thinner with about half the radial depth, and weight, and are made of steel, not cast iron.
DSS pistons have had some pin bore issues as well.
And the Mahle pistons come with .984(Mopar) pins because is it allows the shop to hone the rods for the exact right fit, whether it be for a floater or press.

Somewhat questionable info here.

 

There's always better choices in the mopar pins vs. .980 pins., and bear in mind the Mahle are state of the art in piston design IMHO. Seems there are 2 good choices and one that priced their selves out of any competition !
Hyper pistons have scared me off of any cast pistons, but RA has them for a sbc 350 for $140 & change - no where near $700..

 

Not sure why you would say that ? What do you think is in 90% of the production engines now days including all of the LS, Late Hemis etc ? These are the same engines that guys are putting Prochargers or Nitrous on and having no problems.

However it is just like anything else . . . . . you get what you pay for.

 

Bill, my reasoning is just based on them being prone to break, (shatter), under detonation which is much harder to tune for a novice compared to computer controlled ignition and fuel in our old cars using carbs and conventional ignitions. (as I'm sure you are aware of).
I do see your point in a relatively mundane application their being an okay option. His engine - his money !

Old design cast being so close to the price of forged in my opinion is a deal breaker. You can pony-up just a bit more and enjoy more tuning assuages and gain HP too. $.02 (worth less than ever !)

 

Bill, my reasoning is just based on them being prone to break, (shatter), under detonation which is much harder to tune for a novice compared to computer controlled ignition and fuel in our old cars using carbs and conventional ignitions. (as I'm sure you are aware of).

Old design cast being so close to the price of forged in my opinion is a deal breaker. You can pony-up just a bit more and enjoy more tuning assuages and gain HP too. $.02 (worth less than ever !)
I do see your point in being that in nearly all mundane applications them being okay ! His engine - his money !