My 97 h1 started burning coolant this last winter. I realized how much I hated the gmc 6.5l diesel and wished my hummer had something better. So after some research I found a 454 uses the same 4l80e trans, & engine mounts. I have already purchased a used gen6 454 and am having the local machine shop overhaul with all new and modified parts!

Asking for info & input from others who have done one of these swaps or know of someone who has. Things like which headers work best, rerouting the exhaust, running a throttle cable through the firewall, cooling piping moods, does the 454 engine driven fan still work with the existing cooling stack?

My goal is to complete this task this year and hopfully document the entire project for others to see and use when their 6.5l engine dies!

 

don't know anyone that has gone from the 6.5 to the 454.

 

i have seen a couple back in the 90's that melted the dash panals due to the heat given off by the engines exhaust. you will have to do a body lift and a lot of modifacations under the hood to fit the engine. and than the last question would be can it meet emission standards for where you live to get registered. in california, the DMV did inspections on all diesel vehicles to make sure that they were still diesels before giving out there registrations.
sounds like a nice build, good luck