[blykins]

Yes, 26 spline.

The RAM clutches have a more aggressive disc, which increases the power capacity.

The Centerforce clutches really have a lot of issues. Typically, they won't hold the horsepower that the McLeod/RAM clutches will. Their pressure plates are OEM replacement plates made by either Luk or Valeo, and they are modified by adding weights to the fingers. In some cases these counterweights will not actuate until very high rpm, so up until that point, the holding capacity isn't much more than a factory/stock clutch kit, unless the disc is upgraded.

Is this a street only car with street tires, or will you have it on the track?

Given the horsepower update, I would go with the Powergrip. I run the Powergrip and Powergrip HD clutches in a lot of very high horsepower applications, including some 7.50 1/8th mile SBF's running full slicks.