Pros and Cons of getting bigger valves,(Dino need your contribution)

Hi guys;
I recently scored a 99 4.0 and i will be building a stroker using Dino's website and the Ghost's post on his stroker. I am considering porting the head first (done that on my NON HO head using Dinos article) and getting the big valves that Mike at accuratepower sells(Intake 2.02" Exahust:- 1.625", wanted to know what you guys think about it ad the pros and Cons associated with it.

Thanks;
ravi

This is what I said on the stroker board:

There's no doubt that a stroker would benefit from the extra breathing
capacity that would come with a big valve head, with a concomitant increase
in HP output and more torque particularly from 3000rpm upwards. The
downside, as I see it, is that the 4.0 head was never designed to accomodate bigger valves and the combustion chambers are small. The result is valve shrouding at low valve lifts. The stock valve head already suffers from exhaust valve shrouding but I solved that problem with my home porting job.
With bigger valves, not only do you have more exhaust valve shrouding but
intake valve shrouding also becomes an issue. Unfortunately there's little
room in the combustion chamber to unshroud them without breaking outside the margins of the head gasket bore. Ultimately the HP gain from going to a big valve ported head is only slightly higher than that from a ported stock
valve head due to the limitations of the 4.0 head design.
I'm also building a 4.6L stroker but I'm going to keep stock sized valves. I
have my spare '92 head that I'm going to port in similar fashion to my last
head, except that I'm going to open up the ports and valve throats a little
more on this occasion to meet the stroker's higher demand for air. I've
already worked out the dimensions that I'll be aiming at. Basically the
intake ports will be 43mm x 37mm (rectangular) and intake valve throats will
be 42mm diameter. Exhaust ports will be 37mm x 34mm (elliptical) and exhaust valve throats will be 33mm diameter.
_____________________________________________________________
- 1992 4.0 XJ Laredo UpCountry with modifications - 171k miles - AX15, NP231, D35c, D30
Estimated 240hp@5250rpm/280lbft@3500-4000rpm, 1/[email protected], race weight 3465lb
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