Heads anyone...
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Senior User
Joined: Feb 2003
Posts: 395
Likes: 0
From: South Carolina
Heads anyone...
I need some good advice on heads. I have access to a set of Cobra Jet valves that I can put in my stock cast iron heads, and I was wondering how those stock heads, with the new CJ valves would compare to the Edelbrock RPM aluminum heads. I was kinda thinking about buying the new heads, but I don't want to do it unless it's really worth it. What do you guys think? Does anyone have specs for the stock heads for combustion chamber size, intake runner and exhaust runner size, or any idea where I can get that info? Is the flow on the alum heads a lot better than stock? Also, I've heard that you can run higher compression with aluminum heads than you can with iron. Is there any truth in that? Just need a little direction!
Thanks,
Mark
Thanks,
Mark
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Heads anyone...
It takes a very generous amount of work to make stock heads flow as well as the edel heads. Aluminum will allow for higher compression becasue it dissipates heat faster. If you have two equal sets of heads on two equal engines running in good order the iron heads will make more power than aluminum though. It goes back again to the heat dissipation thing. Raising the compression on the aluminum heads will also make up for this. Another advantage to stock heads is they aren't going to warp up on you if you overheat the engine a bit. The newer alloys are much better about handling heat than they used to be. I believe the CJ heads are around 72cc like the edel heads. The edel heads flow 270cfm on the intake and 200cfm on the exhaust. Stock heads flow quite a bit less even with CJ valves. Most of the 427 heads don't even compare to the edel heads on the exhaust. There are benefits to both. It takes quite a bit of professional porting to make the 390 heads flow the same cfm and velocity but can be done.
