Book identification: Book about an adolescent boy interested in WW2 memorabilia, wakes up in different time period.

Question

A while ago (like 10+ years) I read a book that I can't remember the name of. See if you can help.

• Took place in Europe
• Main character was a boy preteen or teen...he was later joined by a girl around his age
• He was extremely interested in WW2 memorabilia
• Somehow he & the girl travel back in time & get to meet Elvis (I want to say they got in an old humvee with some crystals in it....)
• There was a bad guy, but I honestly don't remember what he was after... something the boy had that could bring him to his proper time (some sort of magic crystals I think...)
• He ended up blowing himself up somehow & waking up in his own time period.

I know this is very vague but it's been a while. I feel like the name is on the tip of my tongue but can't for the life of me remember it.

Answer 1

Could it be Conrad's War by Andrew Davies?

I don't remember Elvis, or a girl, and it was more about WW2

Conrad loves everything about the guns. And the army. And war. Nobody in his family takes him seriously - until the night he smashes a tank through the living room wall. Like it or not, Conrad's war is coming to exciting, terrifying life... A book for boys of all ages.