413 into 426?

[73ChargerSE]

Just picked up a free 413 short block that I may put into my '64 426 Street Wedge car. I have read that a .070 overbore on a 413 will make it a 426, which is essentially what I am going for.  Assuming that this is safe to do with the motor, I would be able to use stock 426 pistons, correct?  What bores are usually acceptable for a 413?  Will my cylinder wall size be too thin to accomplish this?  Looking at logistics or if before I go in too far with it.

Thanks!
Paul

[firefighter3931]

A buddy has that exact same combo in his 64 Polara 500.....the block started out as a 413 motorhome engine and was punched out .070 to make a 426 street wedge 

He had the block sonic checked but it has plenty of cyl wall integrity and could have gone to .100 over, no problem. 

The finished bore diameter on a 426 RB is 4.25in....same as a 383 B engine.



Ron

[chargerbr549]

We have made a 413 into a 426 several times, for one piston availability seemed to be way better and a good recommendation would be to probably sonic check it before any work is done.

Kevin

[73ChargerSE]

Kevin - What did you overbore? .070 or .060.

Or should I just ask the shop to do a 4.25" bore?

[Challenger340]

We have made a 413 into a 426 several times, for one piston availability seemed to be way better and a good recommendation would be to probably sonic check it before any work is done.

Kevin

Great Advice.
The earlier 413 Blocks would seem to have been thicker, albeit, maybe why the evolution to the 426 ? 
but,
never hurts to check to be sure.

trivia; I've punched lots of old Poly's .090", of the same vintage as the 413's, plenty thick !

Bob out.

[firefighter3931]

Kevin - What did you overbore? .070 or .060.

Or should I just ask the shop to do a 4.25" bore?

Get the pistons first and mic them out before boring. 

The last few thousandths will come with the finish honing process. 



Ron

[aifilaw]

Kevin - What did you overbore? .070 or .060.

Or should I just ask the shop to do a 4.25" bore?

Get the pistons first and mic them out before boring. 

The last few thousandths will come with the finish honing process. 



Ron

Correct
should be able to get away with stock 426 pistons...
the 413 wedge block is almost as good as the average 383 as far as being able to bore it out to an extreme. I've only worked on one personally, but the machine shop I used to deal with all the time (mopar only) said they have punched dozens out to 0.1 with room to spare.