New heads

[885.0conv]

I was just wondering about how long does it take for new heads to break in (when the are at there best hp wise). Are they pretty much the same hp when you bolt them on or do they get better? Could be the tranny since its automatic but it seems that some mornings I have more kick when stepping on the gas. Maybe a shift kit would keep it in the higher kick range.

 

[347HO]

Head don't get "better" with usage.
In almost every case, they lose performance.
You have to consider the beating the valve seats take.
Valve springs lose their tension, especially do to improper oiling.
Normal buildup of deposits.

 

[old_blue]

morning is probably due to the colder air you are sucking into the intake and will make it run better. As the engine warms up and outside temperature warm up the performance will start too suffer.

 

[NIKwoaC]

morning is probably due to the colder air you are sucking into the intake and will make it run better. As the engine warms up and outside temperature warm up the performance will start too suffer.

+1, Its mostly due to the temperature difference. As the engine begins to soak in heat, and as the outside air temp increases, the engine will make slightly less power. I notice it in my car too. Also, cars tend to perform better in the early spring/late fall, when air outside is nice and cool, which makes it more dense. Same concept behind a "cold air intake".