I was just looking around on youtube and came across these 2 videos.
http://www.youtube.com/watch?v=ppPZsI7Xy30http://www.youtube.com/watch?v=APCl012FXhs&NR=1It shows a guy putting a 292 crank in a 250 and it clears just fine. The only problem is that the connecting rods were too long and it pushed the piston out the top of the block. Couldn't you use a 292 crank in a 250 as long as you got short connecting rods? Would there be an advantages/disadvantages?
It will work, but to get a rod and piston combo to work, you have to remove some material off of the crankshafts counterweights on the OD to make it work. You also end up using a very short connecting rod, which places a greater amount of side load on the cylinder walls. The extra money you will spend to do this will likely outweight any benefit you could ever gain by just either building a 250 or a 292 using conventional speed parts. IMHO....
I think twisted 6 was getting 1000.00 to prep a 292 crank for a 250, please correct me if I'm wrong. And that will buy a lot of nitrous. Or, a really nice blow-through turbo carb and hat from CSU. Or, a used HX40 off ebay and a SPA T3 turbo manifold. To say nothing of the custom pistons you will need - which will undoubtedly have the wristpin up in the ring pack, drastically reducing piston life.
Typically, the guys running that setup were roundy-round racers looking to hide their larger displacement engines to circumvent the rules somehow.
I've seen a picture in the old Kay Sissell hop-up book showing his altered Tee Roadster parked with a big hole in the side of his 230 block where his 292 crank pushed a piston/rod combo thru the block, it pushed the camshaft out first. He said don't do it.
Math:
292 deck 10.875"
Rod 6.76"
Stroke 4.12"
Maximum CD 2.055"
Rod ratio 1.64:1 (too small, not that good)
Assuming a pretty small 1.09" CD (expensive custom piston):
250 deck 9.15"
Stroke 4.12"
Rod 6.00" (common SBC length)
Rod ratio 1.456:1 (very bad)
Slightly more practical, much more expensive:
De-stroke the 2.10" journal back to 2.00" to lose some stroke
Stroke 4.02"
Rod 6.00"
CD 1.14" (expensive custom piston)
Rod ratio 1.49:1 (not quite as bad)
Best idea: get a 292
A 292 crank in a 250 Chevy block may not be that interesting, but some of the Pontiac guys have put the 292 crank in the OHC 250 Pontiac engine. No cam to get in the way.
There used to be a Pontiac web site that had some guys doing that. The site is long gone so I don't know how they held up.
And it has the same rod problems.
Alrighty guys thanks for the responses. It's just that I have the original 250 for my car and I was wondering if putting in a 292 crank was a viable performance option. Guess not!
"Original" is a much over-valued feature, IMO.
If the car was originally expensive, rare or special, keeping its original parts has merit. An old used car does not become a collector's item unless someone wants it.
I have yet to hear of a prospective purchaser refusing a modified car (that they otherwise wanted) on the basis that the engine has been improved.
You should visit a Barrett Jackson or other auction some time, the number matching and origianl cars bring a healthy premium, even a modified car wil get more if it has the original engine in it, but it depends on the buyeer as you stated " unless someone wants it"