texas94z

whats up guys. i am starting to prepare for a new project in a few months and i have a few questions about an all iron engine. i am planning to build a 454 bbc with a 80mm+ single turbo with a built th400. what are the advantages and disadvantages to iron heads? its going to be a budget build and i dont want to throw tons of money on great flowing bbc aluminum heads. But, can i make a good set of iron heads with a budget? i really want a bbc for my project but if i have to go sbc with aluminum heads for the performance gains i will. i know nothing about iron heads and how they perform compared to aluminum heads. so any feedback with be great.

btw i decided to build a 454 for a chevy truck.

Injuneer

Its not all that clear cut. Aluminum heads are lighter, easier to port. But they lose heat faster, so you have to bump up the compression ratio to compensate for the reduced thermal efficiency. You may also be able to gain a small edge with increased spark advance. Flow-wise, there's no reason identical aluminum and iron heads can't be ported to flow the same. But many stock iron (or stock aluminum) heads have porting limitations that aftermarket aluminum heads might not have.

rskrause

Iron heads can make good power, as Fred said the iron v. aluminum is not so much the issue (except for weight) as is the design. Iron is also a BITCH to port and very difficult to repair (though a lot stronger than aluminum). Most factory iron heads are small port/low performance. I do believe there were open chamber, rectangle port OEM iron heads made but I suspect they are rare and expensive.

If you are looking for an aftermarket head, the Dart Iron Eagle is a very nice iron head which illustrates a big advantage of iron heads, they are cheap. You can buy a set with springs and valves starting at about $1,400. A comparable set of Pro1 aluminum heads will set you back about $2,500. Do not try to home port an iron head though, it is a complete PITA and really no one likes to port them. The iron is about a bazillion times harder to cut than the aluminum.

Rich

texas94z

i want the engine to be bullet proof. i think i am going to run n2o because i cant afford a turbo build with expensive high flowing aftermarket heads. i think i wiil throw all the fuel into the engine as possible. but if i go n2o and run a high compression ratio do i need to worry about thermal efficiency with iron heads? will the heads get to hot to perform well?

rskrause

Iron does not transfer heat as well as aluminum - more heat stays in the CC and this may make more hp. OTOH, the surface temps in the CC are hotter and this is why you may not be able to run quite as much compression or timing, which may cost a few hp. As far as "bullet proof" goes, there is no reason to choose one over the other. If you can afford much in the way of a head, iron may be the way to go.

Rich