I've moved this topic to the Technical section as it's a better fit there.

Here’s the link to a previous discussion about stroker cranks.

http://www.y-blocksforever.com/forums/Topic27324-3-1.aspx

Performing a search on this site will bring up several different threads on this subject.  While there are several companies doing billet crankshafts, I use Moldex almost exclusively for the billet cranks for the Y.  I’ve used Velasco for billet crankshafts for other engine families but have never tried them for a Y billet crankshaft.  Tom Lieb at Scat has been involved in discussions to make a production stroker crankshaft for the Y but there’s been no headway on that end yet.

If you want big cubes, you need to go with the billet crank, as a cast crank offset ground gets really weak when ground smaller.   The 292 forged steel truck cranck can be welded up and ground, but the welding increases the chance of breaking greatly.

I broke a forged steel crank at the track, but it had been welded and ofset ground.  Ruined ever part of the motor including pulleys, pan, ati balancer, heads, aluminum timing cover, aluminum water pump, and split the block in have down the center.  It did last almost a year though.

A 312 crank should work fine if you stay away from Nitrous, blowers and manybe dragstrips.  A manual transmision and good slicks may have contribute to breaking parts as well.  

For most people and offset 312 crank would last forever, especially with an automatic, until you jump up to the next level of performance or want big cubes.

The weakest part of a Y-Block is the rods, do not ever use stock rods if plan to make any power at all.  Mummert has a drop in perfomance rod that is very economical for312's.  Much cheaper than destroying an engine every year.

As Glen brings up, the rod journal oil hole creeping towards the edge of the journal is just one problem to watch for when offset grinding those cranks.  Another problem to watch for is breaking into the oil hole at the rod journal filet or radii when grinding the journal to the smaller diameters.  If you have a variety of crankshafts to pick from, then looking at the rod journal oil hole locations in detail can help you pick out a crankshaft that will offset grind to the smaller sized journals with less chance of problems.  Here are some past discussions going into more detail on the filets in particular. 

http://www.y-blocksforever.com/forums/Topic31049-3-2.aspx

http://www.y-blocksforever.com/forums/Topic61281-3-1.aspx

http://www.y-blocksforever.com/forums/Topic7173-5-2.aspx

And here are some links regarding offset grinding Y crankshafts in general for more stroke.

Crankshaft options

Crankshaft filet radii

Offset grinding for more stroke

Using a 312 crankshaft in a 292 block

If you do a search you probably see most of the information you require. There are four options. Original rods for original stroke 272/292 these can be improved with ARP bolts. Eagle H beam rods are used in stroker applications by reducing the diameter of the big end journal by offset grinding. These are essentialy scrub rods. There are forged truck rods C1TE that go with the steel crank these are the right lenght for 312. Also John Mumert list I beam aftermarket rods for 312.

Also if you look at the racing section you will see a thread on "new blocks" the idea is being thrashed around but at 4.125 bore these will be a big block y block. Or is that a big y block or y big block. If it eventuates that will give you some cubes.

cheers

Warren   

The connecting rod design will dictate how much stroke is possible as the rod to camshaft clearance is the limiting factor on the Y engines.  All other crankcase areas will allow for a significant stroke increase without clearance issues.  With the 1.889” journals (Honda), I’m doing the 4.000” stroke with the Eagle 6.300” H-Beam rods for Y builds.  There’s no special base circle reduction on the camshafts as I’m going for as much lift as possible.  I do put a small chamfer on the camshaft side of the rod around the top of the rod bolt threads though to insure a minimum of 0.050” clearance between the rods and the camshaft lobes.

Best Regards,

Jeff