diff --git a/common/src/main/scala/org/apache/comet/CometConf.scala b/common/src/main/scala/org/apache/comet/CometConf.scala
index 142b2d159..5d86d3c5d 100644
--- a/common/src/main/scala/org/apache/comet/CometConf.scala
+++ b/common/src/main/scala/org/apache/comet/CometConf.scala
@@ -378,7 +378,9 @@ object CometConf {
 
   val COMET_CAST_ALLOW_INCOMPATIBLE: ConfigEntry[Boolean] =
     conf("spark.comet.cast.allowIncompatible")
-      .doc("Comet is not currently fully compatible with Spark for all cast operations.")
+      .doc(
+        "Comet is not currently fully compatible with Spark for all cast operations. Set this config " +
+          "to true to allow them anyway. See compatibility guide for more information.")
       .booleanConf
       // TODO change this to false and set this config explicitly in tests where needed
       .createWithDefault(true)
diff --git a/spark/src/main/scala/org/apache/comet/expressions/CometCast.scala b/spark/src/main/scala/org/apache/comet/expressions/CometCast.scala
index 9274f1f18..f66801732 100644
--- a/spark/src/main/scala/org/apache/comet/expressions/CometCast.scala
+++ b/spark/src/main/scala/org/apache/comet/expressions/CometCast.scala
@@ -62,16 +62,14 @@ object CometCast {
         Incompatible
       case (DataTypes.TimestampType, DataTypes.LongType) =>
         Incompatible
-      case (DataTypes.BinaryType | DataTypes.FloatType, DataTypes.StringType) =>
-        Incompatible
-      case (DataTypes.StringType, DataTypes.BinaryType) =>
+      case (DataTypes.BinaryType, DataTypes.StringType) =>
         Incompatible
       case (_: DecimalType, _: DecimalType) =>
         // TODO we need to file an issue for adding specific tests for casting
         // between decimal types with different precision and scale
-        Compatible
+        Incompatible
       case (DataTypes.StringType, _) =>
-        canCastFromString(toType, timeZoneId)
+        canCastFromString(toType, timeZoneId, evalMode)
       case (_, DataTypes.StringType) =>
         canCastToString(fromType)
       case (DataTypes.TimestampType, _) =>
@@ -92,7 +90,10 @@ object CometCast {
     }
   }
 
-  private def canCastFromString(toType: DataType, timeZoneId: Option[String]): SupportLevel = {
+  private def canCastFromString(
+      toType: DataType,
+      timeZoneId: Option[String],
+      evalMode: String): SupportLevel = {
     toType match {
       case DataTypes.BooleanType =>
         Compatible
@@ -111,8 +112,9 @@ object CometCast {
         // https://github.com/apache/datafusion-comet/issues/327
         Unsupported
       case DataTypes.TimestampType if !timeZoneId.contains("UTC") =>
-        UnsupportedWithReason(
-          s"Unsupported timezone $timeZoneId for cast from string to timestamp")
+        UnsupportedWithReason(s"Unsupported timezone $timeZoneId")
+      case DataTypes.TimestampType if evalMode == "ANSI" =>
+        UnsupportedWithReason(s"ANSI mode not supported")
       case DataTypes.TimestampType =>
         // https://github.com/apache/datafusion-comet/issues/328
         Incompatible
@@ -131,7 +133,7 @@ object CometCast {
       case DataTypes.TimestampType => Compatible
       case DataTypes.FloatType | DataTypes.DoubleType =>
         // https://github.com/apache/datafusion-comet/issues/326
-        Unsupported
+        Incompatible
       case _ => Unsupported
     }
   }
diff --git a/spark/src/test/scala/org/apache/comet/CometCastSuite.scala b/spark/src/test/scala/org/apache/comet/CometCastSuite.scala
index 1481d2f2e..ad7619285 100644
--- a/spark/src/test/scala/org/apache/comet/CometCastSuite.scala
+++ b/spark/src/test/scala/org/apache/comet/CometCastSuite.scala
@@ -65,8 +65,6 @@ class CometCastSuite extends CometTestBase with AdaptiveSparkPlanHelper {
             } else if (!testExists) {
               fail(s"Missing test: $expectedTestName")
             }
-          } else if (testExists) {
-            fail(s"Found test for cast that Spark does not support: $expectedTestName")
           }
         }
       }
@@ -543,10 +541,15 @@ class CometCastSuite extends CometTestBase with AdaptiveSparkPlanHelper {
 
   test("cast StringType to TimestampType disabled by default") {
     val values = Seq("2020-01-01T12:34:56.123456", "T2").toDF("a")
-    castFallbackTest(
-      values.toDF("a"),
-      DataTypes.TimestampType,
-      "spark.comet.cast.stringToTimestamp is disabled")
+    castFallbackTest(values.toDF("a"), DataTypes.TimestampType, "Unsupported timezone")
+  }
+
+  ignore("cast StringType to TimestampType (fuzz test)") {
+    // https://github.com/apache/datafusion-comet/issues/328
+    withSQLConf((CometConf.COMET_CAST_ALLOW_INCOMPATIBLE.key, "true")) {
+      val values = Seq("2020-01-01T12:34:56.123456", "T2") ++ generateStrings(timestampPattern, 8)
+      castTest(values.toDF("a"), DataTypes.TimestampType)
+    }
   }
 
   test("cast StringType to TimestampType") {