porting Iron heads

[ericjon262]

I know I know, 3x00 heads flow way better but for what I'm doing I prefer the Iron head.

I do have a few questions though;

1. are all iron heads the same?
2. can the hump in the floor be removed/does it help to remove it?
3. what are the biggest valves that can be installed on the stock iron heads?
4. can the iron heads be bolted to the 3x00 blocks?

any input is appreciated, and all related pictures worshiped!!

[neophile_17]

I did some mild port work on the race car heads mostly because they were off and it didn't cost me anything. After reading up on it the concensus was that the fin should stay. This fin was present in V8 heads of the era as well and they reported the same thing. I know some iron heads came with smaller valves. The 3.4L iron and Fiero heads are the same.

Here's some info on iron heads with a 3x00 block.

http://www.fierosound.com/34engine/3400details.htm

And what exactly is the advantage of keeping the iron again?

~sam

[bob442]

And what exactly is the advantage of keeping the iron again?

~sam

X2?

[ericjon262]

there isn't one, I just have them and the remains my old 2.8 and figured I'd see what I could do with them. maybe get another Fiero and see how much my "improvents" would net.

[neophile_17]

If you're trying to learn porting this is probably a decent way to do it. I'd recommend you build a flow bench rather than shooting in the dark. Good luck.

~sam

[bob442]

I would say it's easier to learn with aluminum heads

[geoffinbc]

Yea aluminum heads would be much quicker to learn on. But hey "Run What You Brung". If you have a ton of leftovers that you can make a motor out of then go for it.

[ForcedFirebird]

Don't remove the vanes on the floor. You will have spent that time making your heads flow as good as stock. They are there to help make the air turn. Think like running tap water and putting your finger halfway in the stream, the water will "bend". Same holds true for airflow.

[ericjon262]

Thanks for all of the advice, I was kinda thinking along the same lines with the vane.

as far as iron Vs aluminum, I'll do aluminum heads for my 3500 build for my Fiero, this motor will probably end up in a gen 2 cavalier or an S10.

[Kaiju Senso]

Thanks for all of the advice, I was kinda thinking along the same lines with the vane.

as far as iron Vs aluminum, I'll do aluminum heads for my 3500 build for my Fiero, this motor will probably end up in a gen 2 cavalier or an S10.

That's a sigh of relief. I would have been sad if you put the Fiero iron heads on that 3500 you got...

[ericjon262]

no way I'd swap to Iron heads on a 3500! I may look dumb but it's just a disguise!

[ericjon262]

I would say it's easier to learn with aluminum heads

I'm going to disagree here, aluminum is much softer than iron, so it would be easier to go to deep, or gouge the aluminum than the iron. with porting, more can very quickly become less...

[neophile_17]

Also iron doesn't clog your tooling. Not annoying enough to forgoe Al but frustrating when you're trying to learn.

~sam

[ericjon262]

I've heard you can dip the grinding stones in transmission fluid and they won't clog, I would just use a carbide burr and slow it down a little, it won't clog as long as you don't spin it too fast...

[Blacktree]

According to the Chevy V6 Power Manual, those fins in the intake ports increase flow by 15%. So don't remove them.

However, the exhaust ports have some lumps in them that can be shaved down.

I would also suggest port-matching the heads to the lower intake manifold, and doing some bowl blending. But do NOT port-match the exhaust side. The exhaust ports in the heads are smaller than the manifolds for a reason (to help prevent exhaust reversion).