I ordered a 78 DT400 piston. Im going to do some comparisons of my own and figure this out. I know you guys think its all very clear but it isnt to me LOL!! When I get the piston I will know for sure in about a week.

Sorry that my earlier posts in another thread had created so much confusion, but when someone says they want to use thus and so top end on their DT400, I was thinking a top end consists of a cylinder, head, and piston . . . (as well as the related small end parts), and that a bottom end consists of the crank and rod.

As akara1 just stated, a conversion is possible as long as you use the correct matching rod and piston.
What i was trying to say, is you can't mix and match the piston and rods of the two different designs . . . but wasn't very clear about that.

Carry on troops !

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This is what I needed to see for myself. A side by side comparison of a 77/78 DT400 piston and a IT400 piston. Now I see why a stock DT piston needs to be used if one is using a stock 77/78 DT bottom end which has the shorter rod.
So, that is what Im going to do! Im going to use a Weisco piston for a DT400 and build this beast LOL!
Now I have to figure out a pipe. I am going to keep the battery on the original left side. Maybe I can make a pipe out of the 2 pipes I have now.

Blazer,

very interested to know how you get on with this project, as i have thought of doing this myself. the standard DT400 is just not quite powerful enough for me.

please keep posting.

cheers
les