Here is my situation.I've purchased an old rigid Harley Panhead frame that has been chopped 70s style.I am totally new to bike building and need to know what engines may fit in this frame.My plan is to buy a crashed Harley at auction- l know of a few places in my area- and then use the drivetrain and electrical set up in my frame/rolling chassis.

I've been told that a modern (mid 80s and up) sportster engine wo not fit.But, what Harley engine will?l can not afford to go with a new S and S motor or anything like that.I will even consider a Japanese V-twin if l can get it for the right price and it fits.l wanna get rolling on this bike!

Thanks!
Edit:Thanks for the responses guys.I am sure my frame was not the best choice, but live and learn right?Luckily, the frame has been modified quite a bit already so that it may accept a ''taller'' engine.I will just have to check specific dimensions.One way or the other, I am sure I will find an engine that will ''work''- i.e. most likely have to weld new mounts etc.Thanks again.
Ok, so l got somewhat frustrated trying to find a decent Harley engine and since I am also cheap...l decided to use a Suzuki 750 4 cyl engine l already had.It fits and looks ridiculous in the frame, which is what l was going for.This will be a bit of an abomination, but a fun bike.Thanks for the suggestions guys!

You picked a bad start to a new venture. A shovelhead will fit barely but the Evo engine is too tall. Buying a crashed harley will not help much except for the engine as you will have to find most everything else. Good Luck

If you try the Jap motor, the motor mounts wo not fit. You will have to weld new mounts.
Here is how to modify a Shovelhead frame to accept an Evo motor:

http://74.54.120.132/dbbp/tech-tips/frames_01.html

It will give you an idea of what you will be up against if you want to try a different engine.