My 69 Vette does not have the original motor. I am purchasing a fresh 383 Stroker motor. (The motor was from a 69 Camaro). The motor is bored 30 over, keith black 10.9:1 pistons, balanced eagle crank and light weight rods, competition 292 duration .501 lift cam, aluminum roller rockers and roller lifters. The heads are cast. Do I really need to consider aluminum heads for added performance? How much of a difference will I really see? The car is strictly for the street, however; I want decent performance. Any opinions would be appreciated!

 

Specs being equal, aluminum will gain you no power over iron heads. Just make sure you understand that while there are advantages to using aluminum heads, power is not one of them. They are lighter which increases your power to weight ratio. They dissipate heat more efficiently so your engine will run a bit cooler which will also allow you to run a higher compression ratio which in turn can be used to make more power. They certainly have their value and can definitely be worth the extra money over iron heads.

 

Generally aluminum heads are more powerful due to the fact that they're easier to shape... and most modern head designs are aluminum, because people aren't really willing to buy iron anymore.

Post above is right though, two identical pieces of metal will flow pretty much the same.

 

Thank you. Since I am just using this car as a "weekend" driver, your response makes me feels as though I really dont need the aluminum heads. Do you agree?

 

Agreed. Spend the extra money on something else. Nothing wrong with iron heads.

 

I agree...nothing wrong with iron heads. Everything being equal...combustion chamber size and design...the air and fuel charge doesn't know or care.

The advantage you gain with aluminum is less weight and its ability to shed heat faster. Shedding heat faster is why some engines can use higher compression with less chance of detonation.

Other than wanting very high compression, for a street car you really won't gain much if anything by going aluminum other than its probably costing more.

A properly matched set of components for the results you want will go further than simply bolting on aluminum heads.

 

I have to disagree. The OP has a full roller 383. An upgrade to AFR 195 heads will probably net him close to 100 HP due to the difference in flow compared to a stock iron head if his intake is matched to them. The bottleneck on a stock engine is the intake, heads and exhaust. With his internals he needs all three.

 

There are a lot of suppositions here considering that the only detail we have on the heads is that they're iron.

Do you have the mfgr or any other specs on the head? We should probably see what you have before we say they're costing you power

 

With the given 10.9 to 1 compression ratio I personally would go aluminum, the 292 duration cam probably has a lot of overlap, you could probably get away with cast iron, but still unless your not running pump gass Id still go aluminum.

 

all that money spent on the bottom and not at the top where you make the power.

 

True, If they are the right aftermarket heads he might not be giving up a lot of power. I would like to know intake manifold, head manufacturer and intake CC and exhaust setup. That bottom end is capable of well over 500 HP with the right heads, intake, exhaust and carb but is likely about 400 if those components are stock. In either case you better have good gearing with that much cam in a vette.

 

Full roller what, rocker arms?
The cam is a flat tappet Magnum cam, nothing special other than my personal favorite cam.

 

I would upgrade to a roller cam while there building it, Hard to make a flat tappet cam live with the oil we have today, and there's 25-30 hp in the cam swap

 

Curious how your car's running with 10.9 cr on pump gas, as quite a bit for a carburated car. Since aluminum heads transfer heat better than cast, can normally tolerate higher cr's a little better. Maybe even an opportunity to drop the cr a bit, with different chamber volume.

 

His first post says roller lifters.?????? You think he is using roller lifters on a flat tappet cam?

 

Roller lifters go with a roller cam. Could be a mistake, I guess. Lets get it cleared up. KJLive, roller cam or flat tappet cam, which is it?


Keep the shiny side up!
Scott

 

Wow! What great dialog! Let me get more details. The motor is not in my car yet. In fact, it is in my friends garage on a stand. He built the motor for his Vette, but a new house and a new baby on the way forced him to sell the project car and now the motor. He stated that everything on the motor is blueprinted. The Holley 650 and high rise intact were sized based on the motor specs. At the time he built the motor, he didnt buy aluminum heads, but rather rebuild the cast heads. Since all of you are extremely knowledgable in comparison to my understanding level, what exactly do you need to now? I will get the details. Thanks to all of you! I appreciate it. I dont want to spend a ton of extra money on something I may not need. However.....if it makes sense....I will go with aluminum.

 

First thing I would do is find out if its a roller cam or a flat tappet cam because that will determine how you break it in and what oil you run afterwards.
A Comp Cams 501/292 is a flat tappet cam, but you state roller lifters, these two items don't usually go together .

 

You said you want more performance? Get a good set of aluminum heads like AFR's as someone already mentioned. Do you really need them? Of course not but then do you really need a 'vette? Get the aluminum heads!

 

Like most have already said with 10.9:1 compression you will have a hard time running pump gas with iron heads, but how is the engine 10.9:1 without knowing what chamber size you have? If its based off 64cc you can buy a head with a larger chamber and drop the comp a bit but you may lose a little horsepower potential also good cast iron heads cost almost as much as good aluminum heads. There are a lot of good heads out there I personally dont like AFR heads but thats just based on a set I bought years ago. Stay away from the cheap Pro Comp and chinese stuff. Spieres racing sell a lot of heads including Air Wolf heads which are extremely good heads probably over most budgets but well worth the $$$