General Motors Corp. is in final negotiations to form a joint venture to assemble Chevrolet Blazer compact SUVs in Russia. The deal may be signed by September. GM is negotiating with ELAZ, which has a massive unfinished automotive complex in Yelabuga, Tatarstan, Russia. ELAZ conducted long, fruitless negotitations with Fiat SpA to build the A93 small car, engines and transmissions at the site, originally intended to build as many as 600,000 cars annually and at least 300,000 engines. GM sources say the plant would initially import complicated high-value parts like engines and transmissions. Blazer assembly could begin in 1996.