Although the 292 rod method has been used successfully, this is high precision work and cannot be safely entrusted to any shop that is not familiar with the engine ("what do you mean, they have different size main bearings?").
The change in compression is a nice plus, of course.
The displacement change isn't really a big improvement - less than 5% (which is generally considered to be the low limit of human sensory perception - you can't detect changes below 5% easily). This makes regrinding just for stroke ineffective as to cost.
The rod angle is slightly worse, but which, while still a fairly reasonable figure (drops from 1.73:1 to 1.64:1) is definitely going the wrong way. A larger engine "works" its ports harder and a larger rod ratio helps slightly here. Unfortunately, even getting the original ratio is very tough: 1.73:1 with the new stroke is 7.14", which requires an expensive (custom) rod and aifferent piston.
There is a potential cam interference problem here as well, where the rod will strike the cam core. I'm not sure at what stroke increment this will occur, but it's very close now and relieving the cam is dangerous due to length and torsional stress.
There are also rods from older engines with even smaller journals which will permit a larger stroke increase by the same off-set grinding method but obviously:
1. this weakens the crank even more (less journal overlap)
2. requires an even longer rod for a good ratio
3. more chance of hitting the cam
Has anyone any data or links for longer strokes?
