Question on rules.

[sparky]

Good day, I just have quick question on the GT rules. 

14-a
Any commercially available cylinder block may be used. An aluminum block may not be used to replace a cast-iron block unless an aluminum block was available in the production engine.

22-a
Engines may be substituted for ones of alternate displacement, or cylinder head configuration, provided that the substituted engine is of the same manufacturer and number of cylinders. By example, any Nissan four-cylinder engine may be used in a vehicle, which originally was equipped with a Nissan four cylinder engine. Any increase or decrease in displacement, or change in cylinder head configuration will require recalculation of the minimum racing weight. North American vehicles competing in GT-1, equipped with a pushrod V-6 or V-8 engine may substitute an engine of the same configuration but with a different number of cylinders.

Does this mean that any block can be used or does the block need to one that was available in the production version of the car its in?  ie. Can an RB25DET (modern straight 6) from a Nissan Skyline be used in a Nissan 240z, etc (with the 1.55 displacement factor due to turbo)?

Thanks,
Brent

[DinoC]

According to Rule 22a as quoted this would seem to be possible, but since you quote the rule 14a , I ask the question, is the Skyline block cast iron or aluminum?
If it is aluminum then the swap is not legal.

[sparky]

It has a cast iron block and aluminum heads.