Shortly after D&D was published in 1974, players at Caltech started working on their own "improved" variant. The initial version was published in The Spartan Simulation Gaming Journal #9 in August 1975. A latter version (The Complete Warlock) was published by Balboa Games in 1978. What many people do not know is Warlock continued to be played and developed in the Caltech area for many years. Long ago, PDFs of 9 rules sections of Warlock circa 1999-2000 were made available for free by the designers on a Fortune City web site (http://www.fortunecity.com/rivendell/highwayman/783/). Unfortunately, Fortune City hosting, like Geocities disappeared from the web some time ago taking these files with it. I discovered my copies of these files on a backup DVD from 7 years ago and decided to combine the files into one PDF in a form that could be duplex printed (this involved adding blank pages to several sections so that each section had an even number of pages). My printed copy in just over 200 pages. I've uploaded this PDF to Mediafire where it is available for free download:
Caltech Warlock Rules circa 2000 (200+ page PDF, about 1.4 megs)
The rules are fairly complete including character classes, magic spells/items, special thief abilities and a very detailed combat system. No monsters, however standard TSR era D&D monsters work fine. The basics of the game from 2000 are still very similar to my copy in The Spartan Simulation Gaming Journal #9 -- just greatly expanded. The combat system is a bit more complex than I remember for the 1970s, but it was fairly complex then. If you aren't lucky enough to have access to a copy of The Spartan Simulation Gaming Journal #9 or The Complete Warlock, this version will give you an idea of what these games were like.
There is a lot of material here that can be added to old school games, including Microlite74. I know I used some of the spells from Warlock in my D&D games in the 1970s. A word of warning: The "Caltech" (aka California) style of D&D was one of the high-powered D&D variants that Gygax ranted about at times in early issues of The Dragon magazine. While such high-powered D&D variants work fine, regardless of what Gary thought of them, you will have to be selective about any material you borrow if you do not want a high-powered California style game on your hands.