Guys I also am running a 383..400 rods scat crank, comp hyd roller xe282 AFR 195. Compression at 10.25:1 I had a small drop off in power swithing from xe284 to the 282hr. I was kinda unhappy with that. Now i have a friend that has a set of pro mag roller rockers like mine but his are 1.6 mine are 1.52. Is it worthe the headach of the swap?? I am also going to swith from dynomax shorties that have 1 1/2 tubes to Fulllength 1 3/4 headers so hope to see some gain from that.

I'd try the 1.6 rockers on the intakes and see how the motor responds. Sometimes they'll like it...sometimes not or no difference.
I'd do one change at a time...the 1 3/4" headers may hurt you too.
My bro-in-law's 180cc AFR headed, Voodoo cammed, 383 runs 12.60s with 1 1/2" headers.

I think I have this right??

I think a short rod motor can use a tad more cam b/c of the piston dropping faster from TDC, so therefore the suck is a bit better just off TDC vs the long rod motor!

NOT by much, but still a tad....

And I think your heads will support the slightly better suck that a slightly bigger cam should allow your motor to make b/c of your short rods.

How far off am I guys??

Imho, you dropped a tad on Advertised duration, so therefore you are probably making more lower grunt than you were before! Not all that much, but some more....

pdq67

Guys I also am running a 383..400 rods scat crank, comp hyd roller xe282 AFR 195. Compression at 10.25:1 I had a small drop off in power swithing from xe284 to the 282hr. I was kinda unhappy with that. Now i have a friend that has a set of pro mag roller rockers like mine but his are 1.6 mine are 1.52. Is it worthe the headach of the swap?? I am also going to swith from dynomax shorties that have 1 1/2 tubes to Fulllength 1 3/4 headers so hope to see some gain from that. If the headers are equal length they should help even if they have bigger primaries. If they are unequal length they probably won't. Like the post above suggests the higher ratio rocker on the intake only is a common mod to gain a few horsepower if the piston to valve clearance is sufficient.