Well, you might consider a lightweight dual overhead cam Ford inline four cylinder...
http://www.quad4rods.com/Catalougue.pdf
Bottom of page 4.

Or an overhead valve inline four cylinder that uses a V-8 small block head...Ford, GM or Mopar.
http://www.kansasracingproducts.com

Send me an email about new and used engines/components.

Regards,
Gerry Dedonis
dedonis@kans.com
785-655-3862