401 with 0.010 cylinder taper... ?

Elliott

With only .010 taper is this something I can run a std piston in with a light hone?

jeepsr4ever

Not without eventually breaking a skirt.

Elliott

Gotcha, thank you sir! Hate to bump up to .030 though...

fifesjeep

If I remember correctly it's .005 or .006" Maximum taper... I need to dig out my Jeep manuals... I'm pretty sure they have all the specs you need to know...

Elliott

Yeah, ok... .005. Thanks for the heads up. With some of the new emphasis on AMC pistons is there anyone doing a .020 piston now or are these still strickly custom?

fifesjeep

.020, .030, .040, and .060" are your standard sizes. Most auto zones or Advance Autos have replacement pistons for AMC... and they're honestly priced decently... Look on ebay, Sometimes you can score a set of forged pistons for cheap...

Elliott

It's been quite awhile since I've checked but I didn't think there were any .020 401 pistons to be found. Last I knew, guys were using 390 .020 pistons and cutting the tops down. I'll check around...

82Waggy

You can get any size you want in a custom forged piston, but once you index the decks you may find it difficult to get one in at even .030. The 401 I just did was out of square and worn about .028 overbore already. Barely managed to clean it up at .040 and had to shift center on several bores to do that.

fifesjeep

82Waggy wrote
You can get any size you want in a custom forged piston, but once you index the decks you may find it difficult to get one in at even .030. The 401 I just did was out of square and worn about .028 overbore already. Barely managed to clean it up at .040 and had to shift center on several bores to do that.

What did all of that extra machine work run you?

82Waggy

Index decks, Bore, & Plate Hone on a Sunnen was around $400.00.

82Waggy

BTW: Having said that about my 401, my 390 squared up in .005" off the decks and the bores came in at .020 with no bore shifting - a much better block than my 401 but it was made back when sombody gave a crap (1969). I used +.040 KB's in the 401 and +.020 forged JE's in the 390.