I have a 292 in my 56. Engine could use rebuild. There is a good (supposed to be) 312 Crank and set of 8 Rods on Facebook Market Place. Supposed to have been salvaged from rebuilt Engine with bad Block. CDN $400 for Crank and CDN $240 for set of Rods. What is involved in using these Parts in a 292 Block?  Worth while if rebuilding Engine anyway? Thanks

  

I did a 312  crank swap many years ago. Ground the mains of the 312 crank to std. 292 size and .010" (in my case) undersize for the rod end. The ECZ rods I had needed resizing so I purchased new 312 "Probe" rods from Mummert. The crank grinder had a narrow stone to allow preserving  the oil slinger at the rear of the crank. With your project, one crank or the other will need to be ground, just make sure the 312 crank has enough metal for a successful grind. It will also be important to rebalance the rotating assembly. I bored my 292 block to stock 312 size and the pistons were replacement Silvolite for 312 engine thus there were no clearance problems due to the rods being shorter. Others will hopefully chime in but this was a very easy worthwhile modification. However, I already had a standard 312 crank in my stash.  Maybe someone can provide some general numbers as to what this mod will do for HP and torque. 

64F100 57FAIRLANE500

I would say it depends on just what you want to do, what you can afford, and if you can find a competent person to do the machine work. I'm building a stroker 292 using Mummert's H-beam Stroker Rods, Autotec 3.825 pistons, B9AE 292 block, and 292 EC crankshaft with rod journals offset ground to 3.46 stroke.

I would be reluctant to use those ECZ rods as-is. Even if they have been reconditioned (resized with new rod bolts), they aren't the best rods to use for a performance application. 

If you're looking to substantially increase performance, you can have the 312 crankshaft rod journals offset ground for 3.51 stroke, but you won't be able to use the ECZ rods.

The 312 crankshafts being installed in the 239, 256, 272, and 292 blocks requires that the main journals be ground to the 292 main sizes.  My recommendation is to first install the main bearings in the block, measure the I.D., and then have the crankshaft ground to the desired oil clearance.  The oil clearance for the mains being between 0.0020” and 0.0025” works for most street Y builds.  Just arbitrarily grinding the crankshaft without first measuring the bearing I.D.’s can have the bearing clearance outside of specification due to the various manufacturing variances both in journal diameters, bearing thicknesses, and bore I.Ds.

Also required will be grinding the 312 crankshaft rear main seal surface down to the 292 size.  The 312 rear seal surface is 2.750” while the 292 size is 2.625”.  If wanting to retain the rear oil slinger on the 312 crankshaft, then a narrow grinding rock will be required.  Not all shops will have that narrow rock but I have been both ways on the crankshaft rear oil seal slinger with no oil leaks using the neoprene seal and completely removing the rear oil seal slinger.

Using the ECZ or C1TE connecting rods will allow any 312 piston to be used.  For bores less than 3.800”, the pin location in the 272 and 292 pistons are the same as the 312 pistons but there may be some clearance issues between the 312 counterweights and the bottom wrist pin boss of the piston depending upon who manufactured the pistons.  Easily fixed if caught during pre-assembly and any balancing that is performed.

The longer EBU connecting rods in conjunction with the 3.44” stroke does create a rod/camshaft clearance issue.  If desiring a longer factory rod such as in the case where the tops of the pistons are machined down accordingly or a custom piston is being used, then the C2AE rods can be used.  These are the same length as the EBU rods.  The C2AE rods have the shorter length rod bolts thus making those rods compatible with the 312 stroke.  The longer connecting rods does require that the pistons have a shorter compression height (wrist pin location) than stock but if going the custom piston route to take advantage of some of the newer piston ring technology, then longer is better.

Offset grinding the rod journals to increase the stroke is another option but is another topic as it requires different connecting rods and pistons.

Here's the link to a past thread discussing how to order custom pistons.
http://forums.y-blocksforever.com/FindPost160000.aspx 

Lorena, Texas (South of Waco)

I have been using another method to put a 312 crank in a 292 block, and I'll mention it here for what it's worth.  I align bore the 292 block to 312 size and fit 312 bearings by grinding the aligning notches for the bearing in the appropriate spots in the block and cap.  I do not bore the rear seal area to 312 size, but leave it 292 size  to used the 292 neoprene seal.  I chuck the crank in the lathe and turn and polish the seal area to 292 size while retaining the oil slinger.  I also turn the top of the slinger to 292 diameter to prevent any clearance issue in the block.  Rod and piston fitment maintain the method outlined by Ted.  I do this in my supercharged race engines so that I maintain the overlap between the main and rod journals.  I have experienced crankshaft cracks and even breakage in that area.  Another reason I do this is because I have equipment to do it this way myself.

John - "The Hoosier Hurricane"

It seems like there is a lot of work involved in taking this route, and you still end up taking meat out of the main saddle bores, for which 312 blocks have been known to crack. Isn't that why 292 blocks are preferred for performance upgrades? Of course, 292 blocks are far more common (and cheaper). 

Blacktie, re-read my post.  I use 292 blocks, not 312 blocks.  I have had no cracked main webs in any of my converted  292s.

John - "The Hoosier Hurricane"

it would be just as easy to pick up a 312 block and in the end be just as cheap.

For what it's worth, if you are going to bore your block to 3.800/3.810", you will only be gaining 12 cubic inches by going to the 312 crankshaft and rod combination.  That is a lot of cost for very little performance increase if any, depending on your compression, camshaft, carburetion, and exhaust system modifications.  I would personally keep the 292 the way it is and just order new pistons with metric ring package and get you the horsepower difference and better mileage.  JMO, Joe-JDC.

JDC

Hoosier Hurricane, I read it correctly the first time. "I align bore the 292 block to 312 size." Isn't that exactly what Ford did to ECZ-A, B, C and B9AE 292 blocks to accommodate a 312 crank? Why, then would doing what you suggested be any less prone to cracking in the main web areas?