[Canadian Charlie]

Well I just got back from the machine shop, I tried to get a crack in the head fixed but that turned into a big mess. So I said to myself that this is the time to get BRAND NEW HEADS, I know alot of you here have more experience than me so I'm asking a few questions

1: How much do aluminum heads weigh vs. iron ones?
2: Who makes a good set for street and strip?
3: I sometimes over-torque headers to the heads, will this be a problem on aluminum?
4: I will be running 10.5 compression if I was gonna be using my last set of heads (GM Bowtie 64cc)
5: What am I looking at in price for a good set (aluminum)? I don't want the cheapest and I can't afford the best

http://www.cardomain.com/ride/1633712/10

[baddbob]

Airflow Research makes about the best flowing alluminum stock 23degree heads available. Which bowtie heads did you originally have on the engine? I've got a set of phase II bowties I was planning on using, this is the first time I've heard of them cracking. Where did the crack form and did it happen after a Nitrous run? Bob

[Canadian Charlie]

The crack formed between the two middle bowls.

Too much compression, nitrous and cheap pump gas

[Garbonzo Bojangles]

Aluminum heads will cut about 50 lbs. off the front end. With the engine combo you have you'll problably want about a 200 cc runner or more. If you want really good heads and don't mind the wait go for AFR 195s or 210s. You can get them complete for about $1300. I got a set of 195s earlier this year and they are very nice and make really good power, however it took 16 weeks to get them! If you'd rather spend less, I've heard good things about the Edelbrock Victor Jr. and Brodix Race Rite heads. Those are about $1000 and you'll get them immediately from Summit.

About the torque, you can strip Al a lot easier than cast iron. Get yourself good header gaskets (or a couple per header is the flange is bent) and you wont need to over-torque.

[Canadian Charlie]

Are the heads I need 23 degrees?

When I finally get my engine assembled I should have 10.5:1 compression with 64cc heads. How much would I have if I was to use 72cc heads?

I'm scared of detonation, I'm using a brand new block and getting new heads so I don't want to blow anything up

[tc33]

72cc chambers should drop the compression to around 9.8 to 1 if I did my math correctly.

Check out the dart heads with 215cc runners. They are 23 degree aluminum direct replacements.

http://www.dartheads.com/sbchpro1.aspx

[bracketeer]

If you want really good heads and don't mind the wait go for AFR 195s or 210s. You can get them complete for about $1300.

Canadian Charlie, $1300? Shipping, duty, brokerage, and tax! Not $1300 anymore. AFRs are known for a pretty long waiting list. Edelbrock's are cheaper. Dart have a good rep as well. I am not going to get into an argument about Dart vs AFR vs Edelbrock. What flows on a bench may not necessarily flow well on your combo. Only a dyno can tell for sure. Just look at what you want to spend. I have 64cc alum heads on a 350 at 10.5 and it works fine on premium gas. I run 70cc alum heads on a 406 at 10.9 compression and have no problems.

[bracketeer]

A large port doesn’t always mean more power. This is especially true with street heads and in some cases, race heads. Velocity is just as important as flow. A smaller port volume generally equates to higher velocity for better street performance. The speed of the mixture determines how tightly the combustion chamber is packed. The more tightly packed the combustion chamber, the more pressure is developed when the mixture is ignited, pushing the piston with more force for more power. For example: A large port and a big flow number at 0.600" lift means low velocity (especially off-idle to 3500 rpm) and results in less throttle response. For the street, velocity is the key to overall performance.

[Canadian Charlie]

Would it be wise to get bare castings and use my exsisting valves, springs, retainers and so for? My valves have seen better days and I have had them for 10 years, got the heads used.

[bracketeer]

Most aftermarket alum heads use longer valves because the deck is thicker to strengthen the aluminum. Also, to allow for larger lift cams, they not only increase length for the deck but go even longer for larger cam clearance. Thus, most also recommend longer pushrods as well. I always check my geometry before buying pushrods.

[Canadian Charlie]

Looks like I'll be needing more than a new set of aluminum heads


Aluminum heads
Head gaskets to use with Aluminum heads
Pushrods
ARP head bolts
Aluminum valve covers to match the heads

[Canadian Charlie]

All I need to do now is win a lottery

[bracketeer]

I go with chrome covers. They are easier to keep clean and are 1/3 the price. As I said before I' have found that most of the time I do not require new pushrods.

[baddbob]

You can make just as much power with iron heads if you want to save some dollars, there's lots to choose from.

[Canadian Charlie]

I'd rather have the iron heads, but after looking around locally (I live in Europe) the sellers were asking too much money for used iron heads which needed work. So I said for a little more money I could have a brand new set of aluminum heads. I plan on going for the aluminum for 2 main reasons, first they are light weight and I need them sent air mail to Europe (big bucks) and second they look nice.

When I was looking for a used 350 block I found a couple for sale here and the sellers were asking around $1000.00 US dollars for a bare engine block. Thats when I decided on a new GM Performance block which I got for $650.00 US dollars