99 up exhaust manifolds fit gt40 heads?

As the title says, I'm wondering if the 99 up exhaust manifolds that, according to Turdle may not fit the earlier gt40 heads. I want to stroke my 5.0 to 347 among some other mods so that it tows a little better. It's my daily driver, but I occasionally tow an open trailer with a car on it, so I want reliability and a little more power. The weight is around 4500 lbs, but there are some interstate hills I have to deal with, and the stocker really fades on the hills. It won't be turned over 4500 rpm, so I'm not looking for drag racing acceleration, just extra torque. The torquemonster headers sound great, but the lack of communication from the builder makes me wonder if they will even do them on a timely basis. The manifolds are better than my tubular stock headers which are probably cracked anyway, since there is a nasty exhaust leak. I'd appreciate it if someone could tell me for sure if they will work together or not. Thanks in advance!

 

[delexploder]

I have the early style on my 99 p-heads, why do you think the cast ones are better?

 

[biff9703]

Turdle says the cast manifolds flow better than the tubular ones, also, mine are leaking. I understand they have a tendency to crack. I just want to know if I can use the newer manifolds on the older gt40 heads.

 

[delexploder]

I have the opposite so i would think it would work, I did have to alter my EGR tube and im sure you would also, by the way the cast ones crack alot also,

 

[biff9703]

You're probably right on both counts, thanks!