Seafood Penne Pasta Salad

1 1/2 lb. Penne pasta (20 oz.)
2 (12 oz. ea) pkg frozen imitation crab meat
1/2 c. diced onion
1 c. frozen petite peas
1 1/2 c. tomatoes, seeded and diced (about three tomatoes)
1/2 c. celery, diced
1 lb. sour cream (16 oz.)
1 16 oz. bottle Ranch dressing + 3/4 c.
1/4 c. milk
2 tsp. salt
1 tsp. pepper

     Cook pasta according to package directions, rinse in cold water and drain. Mix sour cream, dressing, milk, salt, and pepper together until combined and smooth. Mix together pasta, crabmeat (cut into 1/2 in. chunks), onions, peas, tomatoes, and celery. Pour dressing mixture over pasta mixture. Gently mix together.
REFRIGERATE OVERNIGHT OR 24 HOURS.
Before serving, mix in remaining 3/4 c. ranch dressing and serve.