aluminum 5.3 block???

[IXLR8]

I know exactly what you are saying, but the cooling system is what determines operating temperature, not heat radiation from the block. It might cool slightly faster after shut down, but while the engine is running it won't affect it. If both engines have the same thermostat and cooling system, they will both run at the same temp.

You're still missing the point. The heat transfers better which means fewer hot spots. This faster more uniform heat transfer is the reason you can usually run a tiny bit more compression and/or timing. It doesn't really have anything to do with the thermostat. Do you think the thermostat has total control of all the temperatures inside the motor? It doesn't. It just regulates the water temp.

If you've ever tried to weld aluminum you'd understand. The heat transfers more uniformly through the aluminum part which makes it more difficult to weld. If you aren't careful the whole part will melt. Instead of having a small easy to control weld puddle (as you do with steel), the whole aluminum part can melt and fall out because the heat transfers through the whole part faster than it does with steel. This is a perfect example of why you have fewer hot spots in an aluminum motor.

It also means the radiator doesn't have to work as hard to keep the motor cool. If you had a marginal cooling system on a very hot day, an aluminum motor would help keep the temperature under control.

This superior heat transfer also means that an aluminum head will make slightly less power than an equal cast iron head. But you can usually make up that difference with a little more compression and/or timing.

[truckinL33]

You can argue the benefits of aluminum versus iron untill the cows come home. I don't own cows, so I will not participate. As the thread starter stated, the engine in question is free. This should make the decision a piece of cake, take it! Put ported truck heads on it, and stick a 220 cam on a 114 in it. I think you'll like the outcome.

[kyle.p12]

You can argue the benefits of aluminum versus iron untill the cows come home. I don't own cows, so I will not participate. As the thread starter stated, the engine in question is free. This should make the decision a piece of cake, take it! Put ported truck heads on it, and stick a 220 cam on a 114 in it. I think you'll like the outcome.

I agree!! and even though it doesn't have the sweet heads like the L33, itd still be fun to build and maybe make some money on!!