I replaces a 2-row with a 3-row earlier this year.
The post is some where on this site, any way there is a link that states aluminum and brass are almost identical in heat transfer the main difference is in repair ability.

Brass can be fixer on the trail and good luck with aluminum.

My trouble is with the mods I made to my truck any thing over
4000 rpm in 5th gear in the summer caused the truck to over heat. I still have the 2 row, are you interested shoot me a P.M.
The 3 row

Ralph

1991 Toyota 4x4 Standard Cab Pickup.
engnbldr cam and head.
Doug Thorley Headers
Home Made Cat Backs
30x9.5x15 BF Goodrich All-Terrain M/T KM2