What is an LT4 and how is it different from the LT1?
The LT4 was an improved LT1 developed by GM for the 1996 Corvette, the last year of the C4 body style. The Lt4 was standard equipment in all 6-speed equipped 1996 Corvettes, including the Grand Sport. The LT4 had 330 horsepower, 30 more than the LT1, and sported a new cylinder head with better flowing ports, a revised cam, 1.6 ratio roller rockers, and the trademark red intake manifold. The LT4's upgrades were based on lessons GM was learning during the development of the LS1, which would debut the next year in the C5 Corvette.
A limited number of 1997 Camaro SS's received the LT4 engine thanks to a transplant by SLP. There are somewhere around 99 '97 LT4 SS's out there. Fewer than 10 1997 LT4 Firehawks were also produced.
More on the LT4 and how it differs from the LT1 can be found HERE.