LT4 questions

Are the LT4 intake manifold and heads different then LT1s and if so what was the difference.

Are the LT4 intake manifold and heads different then LT1s and if so what was the difference.
The LT4 heads have a taller intake runner, and flow about 15-20% better than stock LT1 heads. They have larger 2.00" intake/1.55" exhaust valves (vs. 1.94"/1.50" on the LT1). Combustion chamber cc is within 0.5cc. The LT4 intake, as delivered from the factory, is virtually identical to the LT1 intake, except that it has more metal at the top of the runners to allow the intake to be ported to match the taller LT4 haed intake runners, and it has an interference point that prevents its being used on LT1 heads without some machine work.