All Small Six Stupid Question time

[wme013]

In my previous life I had a 250 Chevy. There were folks putting 292 cranks in 250 block to make a short height 292.
Would this work with the Ford 200 block using a 250 crank.
I'm sure custom pistons would be involved. But if your building a stout 200, you're using custom rods and Pistons anyway

 

[pmuller9]

It will not work.
Even if you use a very short piston with a 1.0" CH, the connecting rod length would only be 4.853"
That would result in a 1.24 connecting rod to stroke ratio.

 

[aussie7mains]

In my previous life I had a 250 Chevy. There were folks putting 292 cranks in 250 block to make a short height 292.
Would this work with the Ford 200 block using a 250 crank.
I'm sure custom pistons would be involved. But if your building a stout 200, you're using custom rods and Pistons anyway

No sorry thats a non starter as Bubba223489 has said, The 200 block does not have sufficient block height to do this. If you want a 250, get a whole engine. BTW we have some very nice versions of the ford six down here.

 

[Jmustang_65]

If you want to stroke a 200 you can get a 221 crank from Argentina. Our tech section has a write up.

 

[aussie7mains]

If you want to stroke a 200 you can get a 221 crank from Argentina. Our tech section has a write up.

Seriously you would go to all that trouble and cost for a 10% increase in displacement. Given that outright power is mostly limited by the poor breathing of the log head you will only gain probably less than 10% torque and less BHP. For less cost you could get an iron 250-2v head which will given you more gains. Its certainly my experience that the 2v head gives best results on a 250ci six, spend your money there.

 

[Cox Custom Mechanical]

As long as the crank can fit in the bottom end it can be done. Short rod ratios cam make just as much power as long rod ratios but it takes some consideration into the rest of the engine.

The down side to a 1.25 rod ratio is it places more load on the side of the piston therefore increasing wear.

A lot of people get wrapped up in trying to put the longest rods possible in their engine trying believing its all of a sudden going to free up power, but its not true. Like all engines its about the combination of parts you use to make it work well together.

If its a street engines on cheap pump fuel built to last for years then stay away from the 250 crank. A 221 crank would be ok for a street application but you would need to source it from Australia or Argentina.

 

[rocklord]

How about this. Use a Ford Pinto 4.928" 1.6L rod, and a Yamaha XT600 1.1023" CH piston (3.740" bore).
Offset grind the crank 0.187", giving you a 3.50 stroke. Displacement would be 230cid with a 1.408 rod ratio.

Try to keep this one together.

 

[drag-200stang]

Or give it 15 LBS. Boost and now it thinks it is a 400 CID. but then you had to use anti knock fuel and deal with fuel distribution issues.