[89StangGT]

just throw some new cnc'd trick flows on that bitch.

[hitorx]

Results
When a guy like Mike Blackstone says he is impressed with the results of an out-of-the-box cylinder head that means something. The RHS heads performed beyond expectations. The 180cc head demonstrates great flow in the low and mid-lift range, where the valve spends most of its time, while hitting 270 cfm intake flow at .535" lift. Mike notes that the flow does drop off sharply after .535" which will limit camshaft selection. This flow can be improved upon with some porting and better valves

[hitorx]

The RHS 215cc head is the real performer. Normally with that large of an intake runner you expect to sacrifice low-lift flow. Mike, like many experienced cylinder head specialists, is very cautious that while flow-numbers are thrown around like dyno numbers, the importance must be placed on fuel control. A head that is too big for an engine and that has poor low and mid-lift flow will inevitably make less power. The 215cc head surprised us both with better low and mid-lift flow than the smaller 180cc runner. The larger runner really takes over at .500" lift where it continues to flow well up to .700" and break the 300cfm mark.

[hitorx]

A few years back the FordMuscle Forums were buzzing about a new small-block Ford cylinder head out of New Zealand. The company was Pro-Topline and guys in the states were clamoring to get their hands on them. Unfortunately it never materialized because the company went into receivership (what they call bankruptcy down-under) in 2003. The assets were subsequently purchased through a joint venture between Southern Performance Ltd. and Comp Cams. In case you don't know the history, Racing Head Service was a formidable cylinder head manufacturer and race engine building company in the 60's.

Pro-Topline is now RHS.

Not to be confused with Pro-Comp, a knockoff company casting poor-quality heads in China.

To expand the business offerings the RHS partners started Competition Cams in the mid '70's. As the new business grew larger, the RHS operation and name was idled. The intent was always to bring the name and reputation back when the timing was right. The Pro-Topline situation became that opportunity.

The New Zealand foundry where the heads are cast is actually a purpose built operation for cylinder heads. Every head is CNC produced on a five-axis Mazak system. In fact, the guy who runs the place knows a thing or two about high-quality foundry operations. He had previously set up a wheel foundry which is the largest offshore supplier of wheels to Ford USA. Combine that level of experience with Comp Cams history of dominance in camshaft and valvetrain technology and you have the makings for what should be a very high-quality and high-performance cylinder head.

[nolife]

It seems you are confused that no one is jumping on board and giving you the green light to get these heads. Really though, would you actually want an opinion from someone here that has no actual experience with them? That opinion would seem rather useless to me. Maybe they are outstanding heads and a great value but apparently no one that has been reading this thread has them and understandably, they are not willing to back up any claims about how good they are.

Get them and let us know how you like them.

[1slo5.0]

If you are sold on buying them why are you sitting here trying to justify buying these heads. Go buy them!