can a 413 be bored to a 426 ?

i believe it's a .070 over bore

Yes but I think it's actually .060 over. However since good 426w pistons are just as tough to find as good 413 pistons it's not usually worth it these days. I've read all kinds of stories of guys boring 423's to take 426w pistons, but it's not like 426 pistons are growing on trees these days.

Needs to to sonic tested for sure.

if we sonic test , whats the minim thickness on the thrust side?

413 bore is 4.18 and the 426 is 4.25 a .070 difference. On the other side of the coin is was successfully done lotsa times before sonic testing was ever heard of. Not saying it wouldn't be a good idea though.

Actually 413's are 4.1875 so it's only .0625

Yea an oddball bore the +.060 pistons are 4.2475. friend built one with the still somewhat available pistons and had it finished honed to 4.250.
extra clearance for performance decked the block and milled the edelbrock home ported heads to get 10.5 to 1 ran low 12's
Hughes used to have some old stock pistons can't find them any more problem with the old stock pistons they were about .080 down the hole.
A stock 426 piston would work nice but if you find any they are 30 and 60 over!

I've heard of people boring 413's .100 or more.
TRW/Sealed power used to stock +.100 pistons for 440's??
I sold a block cheap to a guy had rust line where ring sat deeper that +.060 would clean up and I said it needs a sleeve he said no I'm ordering in +.100 pistons this will be the third one i built this way this was 16 years ago ish and the +.100's were still available!

This guy sells 413 pistons does not list the size though!
(?? standard, +.030 +.060???)
http://www.ebay.com/itm/Dodge-Chrysler-4...a#ht_1671wt_808

He also lists a 426 master kit. on his sight for master kits he says list piston size??
http://www.ebay.com/itm/Dodge-Chrysler-4...a#ht_1671wt_808

one of the old chrysler fiends related that when mopar couldnt give away the 426 wedge motors (because of the hemi) to get rid of the backlog they restamped the pads as 413 and started throwing them into newports as a 413---yeah and we have all heard stories about uncle harolds hot rod newport---i was told to look at the block castings which will still show 426----on a related note i found a dana 60 under a 1972 dodge truck with a pinion snubber on it---made me wonder if it was something else thrown out the back door....bob

Well .067 if decks are full spec. still deck it down .027 and with the 413 closed chamber heads milled a bit to make up for the fel pro gasket not hard to get it to 10 to 1 or more.

Easy 9.6 to 1.

Think the original 413 are .082 down!

If you use the old industrial Block 413's with the extra meat in them you can bore to standard 440 comfortably. Stock eliminator guys used them for maxi clones all the time until repo blocks came out.
I have one in my shop that was a warranty block with no stampings. Perfect for a maxi.

IMO A zero deck quench motor is the inteligent build.

Well, I agree, although those numbers are a lot more difficult if you're running open chamber heads - say, if you swapped the poor-flowing 516 heads for later factory iron heads.

I'd also wonder if you'd get in trouble not having valve reliefs in the pistons if you start cutting on both the block and the heads.

I've posted recently that with a .050 cut on my Edelbrock heads, my 413's CR will be about 9.6 to one with pistons .080 in the hole. For a street car, that will be good enough - and a lot better than the 8.5 to one it has now with 906 heads even with steel shim head gaskets. If I absolutely had to have more than the milled Eddy heads will give me, or if I was starting from scratch instead of from a running engine, I'd just switch to a 440 block and use off the shelf pistons to build a zero-deck closed-chamber quench motor.

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yea hard to get the cr with the better flowing open chamber heads. I heard Eddy is coming out with a 75 cc street head??

There are industrial block 413s that are built on a 426 casting number. I assume those would go out to at least 4.28, but that they came 4.1875 like a regular 413.
It used to be that there were cheap standard bore 383 pistons available, which with a 4.15" crank and LY rods would get you 472 inches, now those 383 standard sizes are hard to find for cheap.

As for the open chamber heads being better flowing, I don't believe it. The 915 and 906 had virtually identical ports and flow the same, the 915 was a much better head because of the combustion chamber. The 906 was an EMISSIONS head, built to lower compression and reduce NOx, IIRC.

R.