Thoughts on accepted aftermarket heads for 350?

[Bobby Lundholm]

Originally Posted by Todd Hoven

Great thing about aluminum. You can weld it up, reprofile it, and cover it up. It will look like new and you probably pick up 30 hp at least. You have to do
something to keep up with the Mopars.

Any modifications to the runners are illegal, so if they match up to the stock numbers NHRA will know they are modified.

[Mark Ugrich]

Originally Posted by Bobby Lundholm

Any modifications to the runners are illegal, so if they match up to the stock numbers NHRA will know they are modified.

So if I’m understanding this correctly , you must run the aluminum/ replacement heads in either stock or super stock using the runners as they come from the manufacturer. The exception being replacing the valves and seats with the correct OEM sizes?

[Bobby Lundholm]

Originally Posted by Mark Ugrich

So if I’m understanding this correctly , you must run the aluminum/ replacement heads in either stock or super stock using the runners as they come from the manufacturer. The exception being replacing the valves and seats with the correct OEM sizes?

That's what I'm understanding. The air flow is going to be restricted by the intake regardless, so with the larger head runners i don't think it'll help that much.

[FireSale]

Originally Posted by Bobby Lundholm

That's what I'm understanding. The air flow is going to be restricted by the intake regardless, so with the larger head runners i don't think it'll help that much.

That's what I was told regarding my AFRs. Smaller valves would degrade the heads performance. The shop that does work for Hancock and Lane advised against that route.

[X-TECH MAN]

Originally Posted by Bobby Lundholm

That's what I'm understanding. The air flow is going to be restricted by the intake regardless, so with the larger head runners i don't think it'll help that much.

I know of at least one stocker 428 CJ intake manifold that is 10 lbs lighter in wt. than any others. No grinding on the outside either !

[Bobby Lundholm]

Originally Posted by X-TECH MAN

I know of at least one stocker 428 CJ intake manifold that is 10 lbs lighter in wt. than any others. No grinding on the outside either !

I still don't think you make the intakes big enough to really let the heads breathe. What's the standard CC of the stock Chevy intakes compared to a 185 cc head runner?

Originally Posted by Bobby Lundholm

Any modifications to the runners are illegal, so if they match up to the stock numbers NHRA will know they are modified.

When your done they will pour the same volume. Pass tech, have a great race. That’s why they are welded up. To adjust the runner volume. They will be legal to the inspector.

[Bobby Lundholm]

Originally Posted by Todd Hoven

When your done they will pour the same volume. Pass tech, have a great race. That’s why they are welded up. To adjust the runner volume. They will be legal to the inspector.

My point is that they originally start at 185 cc and finesse them down to 165 cc where the stock ones are NHRA will know they have been modified thus being illegal. We are not talking about removing material and making it look "stock" adding material is whole different ball game. You never miss what you don't know was there, but when runners are smaller than what the manufacturer is saying it makes you think.
Correct me if I'm wrong but I believe welding and epoxy are illegal in stock, so if you do that to get the cc numbers right aren't you illegal?

Sounds like a mystery. The first guy who passes a tech inspection via tear down with these heads, will know the secret. Who ever prepares those heads would get my business if I had a Chevrolet. There are no replacement heads for my combo nor ever will be. I was told “it’s not in the spirit of stock eleminator” There was my answer. This deal is a goldmine for power. I’d work on a set until it passes, and not ask questions on a public forum about it during or after. I don’t have those problems so it
Doesn’t apply to me.


QUOTE=Bobby Lundholm;556815]My point is that they originally start at 185 cc and finesse them down to 165 cc where the stock ones are NHRA will know they have been modified thus being illegal. We are not talking about removing material and making it look "stock" adding material is whole different ball game. You never miss what you don't know was there, but when runners are smaller than what the manufacturer is saying it makes you think.
Correct me if I'm wrong but I believe welding and epoxy are illegal in stock, so if you do that to get the cc numbers right aren't you illegal?[/QUOTE]

[Chris Hardy]

Wouldn't it be easier for everyone, if NHRA just calls it: Every SBC head must be Less than or equal to 185CC's, have stock diameter valves? Then they just inspect for grinding and pour? We all make a ton of power, and inspection is easy. (FYI, the pinch cross section on the Dart 185cc heads are smaller than the stock intake manifold cross section) Thus, the heads will be a substantial gain once a good valve job and flowing is completed.