Edelbrock Manifold Marine RPM Chevy Big Block Oval Port w/ BrassEdelbrock part #2561 Performer RPM Q Jet marine intake manifold is designed for spread bore carbs but also works with Edelbrock square bore carbs without adapter on street 396 502 c. i. d. Chevy V8's with large oval port (1975 and earlier) heads. This marine intake features brass lined water passage and brass flange inserts to cover rear water openings. No provisions for hot air style chokes. Accepts divorced choke, late model waterneck, air