Proving or disproving claims made by aftermarket parts manufacturers is one of the most-critical elements of the work we do. Parts for testing roll through 5.0's Los Angeles tech base on a regular basis, and your Tech Editor also hits the road every now and then, to work with new products at Mustang shops all over the country.

Big Daddy Performance (www.bigdaddyperformance.com) in Lakewood, New Jersey, was one of the stops along our extensive East Coast tour this summer. We wanted to perform a bolt-on/dyno test of Edelbrock's new RPM Xtreme (aka "XT") small-block Ford cylinder heads, which Edelbrock says are made with CNC porting that's designed specifically for for stroked 302-, and 351W-based engines...

Dwayne "Big Daddy" Gutridge and his lead 'Stang wrench, Mike Rozman, were more than helpful in accomodating us, by scoring a 347-powered LX coupe for our project, and providing complete use of the facility and Dynojet chassis dyno for the swap and before/after dyno testing.

Of course, "how did the XTs do" is a question that's probably burning in your brain right now. By now, you know that we won't let that info loose on our Web site until our faithful readers have had their chance to find out first.

So, consider this just another reason why it's good to have a current subscription to 5.0 Mustang and Super Fords. We'll give you some teaser info here, but you have to get the mag to find out the real deal on the 'Stang stuff we work with each month.