258 to 304 odd swap questions

75 CJ-6 with empty 258 engine bay. 75 CJ-5 with donor 304. Will swap over the T15 trans and motor mounts too.
1)I noticed the V8 harness has one or two differences and an extra small modual, etc.......I should be able to just swap the engine harness at the firewall block (passenger side of block) and I shoudn't change anything else or with the dash....correct?
2) How much more does the 304 weigh than the 258? Should I swap the front springs as well or just do the swap and see? The CJ-6 has newer front springs and the CJ-5 has old ones.....I'll have to see. Any input?
3) donor Jeep came with a 3 core radiator......is that standard for the 304?
Thanks
Ed

 

In response to Question 2: http://www.team.net/sol/tech/engine.html

I don't know about the accuracy of that data, I just googled AMC engine weight and found that page.

 

Thanx for posting that link, i was kind of curious about weight also