I found it by working on pontiacs and owned them for 28 years and rebuilding them. . sure the yt parts will bolt on and work and the springs will work but why is it rated at 335 and not all others execpt the ra 1 and 2? by the way still underated. its not just the exhaust that helped it. and why was it an extra cost option? if the engineers built the ra's with a cast cranks, cheap bearings and the same valve train as a regular engine why are they rated at a different hp and rev limit? and if all motors are the same than why are there different casting numbers and block codes? if you wiped out the part numbers then sure they are all the same visually? and why put high performance parts on a 1 bbl engine when it was originally designed for low performance? what sets high performance engines from others is the quality built into the parts that are engineered for racing and street durability.