Really the weight thing was nver an issue with me my line of though is economic only. If I can put together another set of Merlins for the same ammount of money I will. $1200 with the valves is pretty cheap.

The Merlins are $1600.

Zanie- go with the Ferrea super alloy exhaust valves. The Manleys are 2 piece const.

Traviss- the alum heads also have an advantage for blower motors-better heat transfer=less prone to detonation.

Zanie the guides on those heads are bronze.I have a set of the GM performance heads that are Edelbrocks with the GM name on them.Mine came off a zz crate motor.I pulled the heads down and put the Ferrea severe duty exhaust valves in.I talked to Edelbrock about buying there valves but they were a name brand I didn't recognise and they were under cut stems.I was a little nervous of the undercut 11/32 stem so I oppted for the Ferreas.I also had a couple of guides that were tight,as in hard to remove the valve.I don't know who assembles the heads,GM or Edelbrock but ther quality control is lacking.

Another advantage to aluminum is they are repairable. Drop a valve in cast and you are done. Do it with alum and a $50 bill to the welder gets you back in biz. The edelbrocks do come with bronze guides.

Dave

Don't forget that agood aluminum head will allow you to run about 1 point more of compression without any detonation. That higher compression will give you about 5% more torque and 4-5% more horsepower in a big block. If you're runnin twins, check your top speed with a 200lb body in the back of your missle. Then remove the body and check your speed again, you'll be plesently surprised! However the law will be after you for dumping a body off!
Raylar

The thing that makes the Edelbrock heads attractive to me is the price, even if you decided to switch the exhaust valves.

But the price advantage goes away if you need to spend $200 on ehaust valves. I might as well but the Merlins.

Just FYI...

nearly every valve in factory automotive and heavy truck engines is manufactured by Eaton. Manley valves are Eatons, exactly the same valves as the Eaton private label, they just cost 3 times as much. Ferrea also uses some Eaton valves and put their name on em... It is true that Eaton friction welds heads on a lot of their stems... they also manufacture some valves from a solid piece of stock. either way i've seen em on the instron and they can withstand some pretty impressive tensile and side loading with a heckuva long fatique life...

Most lifters, flat and roller are manufactured by Eaton also... even the aftermarket hi performance rollers marketed by comp, crane, isky, etc.

I am an aquaintance of the gentleman that manages aftermarket sales accounts, etc... as well as a few folks with a lot of years of experience working in Eaton's valvetrain dynamics and durability lab...

Where are they available for 1,200 ?