1bigoldman

Okay guys. I just got done reading the Feb. 2012 Chevy High Performance. They did an story on a H&C on a carb'd 6.0L LQ9 with a total gain of 105hp on a dyno.

Cam used was Comp Cams XR281HR and for heads they used RHS PRO Action 225cc heads. They claim that the RHS as cast are as good as CNC ported heads. They seem reasonably priced to me. These would save me $$ over finding some 243's and having them ported.

Has anybody used them? Are they as great as they say? It just seems to be to good to be true.

TIA.

ScottyBG

My 2 cents? Do you see how much the comp performance group spends on adds with that publishing company? Do they ever say negative things about comp products, even the ones that are inferior to competitive products? If I were working for that publishing company I would know where my paycheque comes from too. Pretty much Comp, Holley and Edelbrock finance those publications. I read 'em too, but always consider that when reading the articles.

If you were unaware Comp owns RHS, TCI and several other major names out there.

They may be great heads, I can't say for sure, but I woudn't put down that much coin for a set of heads without some independant data, like talking to a local tuner etc. They know which heads are making power when they tune cars, and which ones are not.

Another option is seeing some cars at the track running them, and talking with the owners. I have not yet seen a set on a car, in RL.

I once built a motor indentically to one in a magazine, same heads, same intake , same cam, and bought the same short block they did. It was a gen 1 SBC. I made about 100 hp less on an engine dyno than the magazine article did. They made about 525 vs my 425. I had an experienced engine guy that works professionaly for a stock car team help me tune it. If it were like 10 or 15 less I'd say it was in fuel and timing, 100 hp not likely? I think it was the difference in the dynos, or they were not correcting thier figures or reporting SAE or the like. In the end I was truly happy with the motor, it was a great street engine, felt nice and strong to the seat of the pants, ran well, but it was no five and a quarter horse monster.

mark21742

I agree with Scotty on this....it is very hard to separate great marketing of a product from a great product. It seems like a lot of your magazines and Saturday shows are nothing but a big add for the highest paying manufacturer.

ctd

iTrader: (1)

I'm living the down a 100 HP right now. I had hoped to be within 50 HP of the model I followed but a 100? The education I'm getting is very good.....the cost of my education is not nice.

Another board member described it this way, you need to find the top super secret shop with top super secret engine builder that has a top super secret dyno....then you have the big number!

My particular motor is becoming drivable, it was not very driver friendly following the model. It has been re cammed, funny thing is no loss to top end power, still down 100 HP however.

I plan to re do the header & collector system next that should dramatically improve the street manners again.The software I purchased to try & try & sort the header tube size, length & collector suggests no loss in top-end & I have arms, legs & fingers crossed there maybe a power improvement.

So back to the original topic regarding the cylinder heads, I know nothing about those particular ones. I have learned allot regarding cylinder heads researching my own short fall of power.......you need to explore other sites to try & sort thru the muck.

mark21742

Also flow numbers can be "manipulated", changed and just down right false, all you have to do to get vompletely different numbers is change one little thing on the flow bench to get better or worse numbers, so your best measurement is still track and et times, not flow benches or dynos

1bigoldman

ScottyBG I did know that Comp owns them.
I am wanting to find out if anybody has used them and get their input. If things were better I would not mind being a test subject. I have at least a year before I will have my car done I have lots of time to hide in the weeds and see what's what.
This is part of my due diligence.

Jason 98 TA

iTrader: (4)

As cast heads will never be as good as a cnc head. The castings just can't be 100% consistant because they by nature have to be a little bit of movement in the cores when casting the heads.

We're finishing up the PRC as cast heads & I'm very proud of them. a 320cfm capable head out of as cast ports. To get that flow all of our PRC as cast heads will get cnc shaped valve guides & hand blending!! If your wanting a as cast head you might check the PRC heads out. They're without a doubt pretty sweet! I'll post dyno data from a car we're testing this week!

gMAG

iTrader: (1)

I've learned that most times, the HP television programs and magazines are infomercials which support their sponsors.
Not saying the products are inferior, but rather each product will be presented in its' best light.

1bigoldman

I would be very interested is seeing what you come up with. I'll have to keep an eye out for it.

Killer5.3

iTrader: (1)

Isn't that the same reason there is variances in flow numbers between sets of heads with exact same cnc port job? There are no 2 sets of cores cast exactly the same I wouldn't think, so even with same cnc program there would be differences in the ports when done?

toby

iTrader: (1)

The rhs heads are made by dart. They are a very good casting and can make alot of power in the hands of the right person.