Replacing MBE Heads.

I recently found a 04 Columbia CL with a MBE 4000 engine. The truck has 456k miles and suffers the head issue, The previous owner had the heads cut too much and they started leaking again. Anyway The Truck comes with another complete MBE out of a wrecked 06 sterling with 96k verifiable miles. What Im trying to Figure out is if the Heads off of the **06 will fit the preEGR 2004 block. Im also debating whether or not to just swap the whole engine, that leaves me with the unknown of whats been done to this engine, heads, egr ect. Im getting the truck so cheap I couldnt refuse. 4k cash rebuilt rears FEDEX maintained all records. Very clean truck working APU as well. Would I come out cheaper dropping a 60 series in it without much difficulty? Just change the wiring harness like the old FLDs? Btw the engine thats out of the wreck has 410@2000 hp and the one in the Freightliner has 450hp@2000 on the ECM

 

410 HP serial is 0460855166

(Currently in truck)450HP serial 0460787011

 

It was easier replacing the engine LOL

 

I will remember that if and WHEN these Gaskets start leaking. where do you get the brass inserts?