With headers, they probably aren't. With the cast iron manifolds, it isn't necessarily WHILE the engine is running that is the issue, its after you shut it down, and there is no airflow thru there, cast iron makes an awesome heat sink.

 

I don't think it's a derail.

The shield is not an air deflector. It's purpose is interrupting radiant heat. Emissivity is the key property here among other things comparing shiney headers to rough/dark factory manifolds. Shiney is higher value, higher radiant heat...

Around town driving is where the influence is greater, which would be associated with laminar characteristics.

This is why I think they are needed even more so with shiney headers.

Edit --
Correction: I always get that reversed on emissivity level. Shiney is opposite.

Are those actual temp measurements you took by the way?

 

Yes, actual temps.
I have an engine oil temp gauge installed that the sensor doesn't have a home yet, so the sensor I strapped to the top of the heat shield to see what the temp was.
I've also shot it with an infrared heat gun after pulling up in my drive, getting the same numbers.
~45min on the hwy, ~7min on surface streets w/lights, then pull up in the driveway and idle... 1min sitting in the drive was the highest temp.

My contention was the shield is to stop radiant heat from the close proximity of the stock cast manifold... the header tube is further away... it should also be remembered that heat rises so less heat is going to radiate down, most of it will go up.

 

I can't get one of the converter/flexplate bolts to line up. I tried every way, but this one never lines up. The pattern must have changed over the years between my old 95 5.2 and the new 99 5.9. Is it okay to grind the hole so it lines up?

 

Snow, you can't grind those, everything has to be balanced. Are you using the 5.9 or the 5.2 flexplate? It has to be the 5.9 flexplate because they are balanced differently.

 

It's a 5.9 flexplate. There is a weight on it. I was hoping that little bit I grind off wouldn't make a difference.

 

Is that the original 5.2 torque converter? If so, you are prolly gonna have to replace it. Grinding it so the bolt will fit will ensure that things are NOT completely balanced, and after the money you have invested in this project, that would be a bad thing to do....

Also, the way they balance the 5.9 changed in 96. Went from a weight on the flex converter, to the weight on the flex plate. So, you have an early model truck, with a later model flex plate, and evidently, the wrong converter for it to match up to.

 

Maybe i'll just put it in cross threaded haha. Nv4500 swap shouldn't be too long!

 

Won't matter if you tear the motor apart

 

So I should use my old 95 5.2 flex plate and buy a 95 5.9 torque converter? And will a $80 torque converter from oreily's be ok?