I found this article, that made me realize I may be sitting on an original factory engine. What follows is a text copy of part of the article, at the end, I left the web site's name so you guys that know about motors can decifer what this monster is. Your help and feedback is appreciated.

Taken from: http://rogue.northwest.com/~lakeside/home/1974260z.htm

The LY is basically a very limited produc-tion Nissan factory works version of the venerable L26 that features a cross-flow cylinder head, instead of the poorly flowing, side-flow design of the stock L26. This head flows enough to be responsible for an 18-20 percent improvement in power over the standard side-flow head, even in modified form. LY motors were intended to be homologated for FIA racing and were used in the factory's world rally exploits. Slightly more than 500 of these motors were made and few working examples exist today. A few are rumored to be in existence in the Unit-ed States, but this is the first time we had actually laid eyes on a real LY motor.
The LY featured three, huge 50mm side draft, two-barrel Mikuni Solex carbure-tors, and a bumped-up cam. Mthough the LY was a very hot motor from the factory

 

no sorry dude ... your engine isnt an LY26 .... that engine is crossflow and yours isnt ....

Rusty Datsun x 3

 

LY sits in in different angle too (to have some clearance for the intake and carbs.) with completely different valve cover.

 

thanks...I'll keep looking-asking...