diff --git a/eth2/fork_choice/src/bitwise_lmd_ghost.rs b/eth2/fork_choice/src/bitwise_lmd_ghost.rs
index 66100dbc12..7667b28b74 100644
--- a/eth2/fork_choice/src/bitwise_lmd_ghost.rs
+++ b/eth2/fork_choice/src/bitwise_lmd_ghost.rs
@@ -34,7 +34,7 @@ fn power_of_2_below(x: u64) -> u64 {
 }
 
 /// Stores the necessary data structures to run the optimised bitwise lmd ghost algorithm.
-pub struct BitwiseLMDGhost<T: ClientDB + Sized, B: BeaconStateTypes> {
+pub struct BitwiseLMDGhost<T: ClientDB + Sized, B> {
     /// A cache of known ancestors at given heights for a specific block.
     //TODO: Consider FnvHashMap
     cache: HashMap<CacheKey<u64>, Hash256>,
diff --git a/eth2/fork_choice/src/optimized_lmd_ghost.rs b/eth2/fork_choice/src/optimized_lmd_ghost.rs
index 3e43e2153b..d2663b2b64 100644
--- a/eth2/fork_choice/src/optimized_lmd_ghost.rs
+++ b/eth2/fork_choice/src/optimized_lmd_ghost.rs
@@ -34,7 +34,7 @@ fn power_of_2_below(x: u64) -> u64 {
 }
 
 /// Stores the necessary data structures to run the optimised lmd ghost algorithm.
-pub struct OptimizedLMDGhost<T: ClientDB + Sized, B: BeaconStateTypes> {
+pub struct OptimizedLMDGhost<T: ClientDB + Sized, B> {
     /// A cache of known ancestors at given heights for a specific block.
     //TODO: Consider FnvHashMap
     cache: HashMap<CacheKey<u64>, Hash256>,
diff --git a/eth2/fork_choice/src/slow_lmd_ghost.rs b/eth2/fork_choice/src/slow_lmd_ghost.rs
index c621870d15..68c4ac5a68 100644
--- a/eth2/fork_choice/src/slow_lmd_ghost.rs
+++ b/eth2/fork_choice/src/slow_lmd_ghost.rs
@@ -13,7 +13,7 @@ use types::{BeaconBlock, BeaconState, BeaconStateTypes, ChainSpec, Hash256, Slot
 
 //TODO: Pruning and syncing
 
-pub struct SlowLMDGhost<T: ClientDB + Sized, B: BeaconStateTypes> {
+pub struct SlowLMDGhost<T: ClientDB + Sized, B> {
     /// The latest attestation targets as a map of validator index to block hash.
     //TODO: Could this be a fixed size vec
     latest_attestation_targets: HashMap<u64, Hash256>,
diff --git a/eth2/fork_choice/tests/tests.rs b/eth2/fork_choice/tests/tests.rs
index fb530ac434..3addb8c0aa 100644
--- a/eth2/fork_choice/tests/tests.rs
+++ b/eth2/fork_choice/tests/tests.rs
@@ -25,7 +25,10 @@ use std::collections::HashMap;
 use std::sync::Arc;
 use std::{fs::File, io::prelude::*, path::PathBuf};
 use types::test_utils::TestingBeaconStateBuilder;
-use types::{BeaconBlock, BeaconBlockBody, ChainSpec, Eth1Data, Hash256, Keypair, Slot};
+use types::{
+    BeaconBlock, BeaconBlockBody, BeaconStateTypes, Eth1Data, FoundationStateTypes, Hash256,
+    Keypair, Slot,
+};
 use yaml_rust::yaml;
 
 // Note: We Assume the block Id's are hex-encoded.
@@ -82,7 +85,7 @@ fn test_yaml_vectors(
     let test_cases = load_test_cases_from_yaml(yaml_file_path);
 
     // default vars
-    let spec = ChainSpec::foundation();
+    let spec = FoundationStateTypes::spec();
     let zero_hash = Hash256::zero();
     let eth1_data = Eth1Data {
         deposit_root: zero_hash.clone(),
@@ -227,23 +230,27 @@ fn setup_inital_state(
 
     // the fork choice instantiation
     let fork_choice: Box<ForkChoice> = match fork_choice_algo {
-        ForkChoiceAlgorithm::OptimizedLMDGhost => Box::new(OptimizedLMDGhost::new(
-            block_store.clone(),
-            state_store.clone(),
-        )),
-        ForkChoiceAlgorithm::BitwiseLMDGhost => Box::new(BitwiseLMDGhost::new(
-            block_store.clone(),
-            state_store.clone(),
-        )),
+        ForkChoiceAlgorithm::OptimizedLMDGhost => {
+            let f: OptimizedLMDGhost<MemoryDB, FoundationStateTypes> =
+                OptimizedLMDGhost::new(block_store.clone(), state_store.clone());
+            Box::new(f)
+        }
+        ForkChoiceAlgorithm::BitwiseLMDGhost => {
+            let f: BitwiseLMDGhost<MemoryDB, FoundationStateTypes> =
+                BitwiseLMDGhost::new(block_store.clone(), state_store.clone());
+            Box::new(f)
+        }
         ForkChoiceAlgorithm::SlowLMDGhost => {
-            Box::new(SlowLMDGhost::new(block_store.clone(), state_store.clone()))
+            let f: SlowLMDGhost<MemoryDB, FoundationStateTypes> =
+                SlowLMDGhost::new(block_store.clone(), state_store.clone());
+            Box::new(f)
         }
         ForkChoiceAlgorithm::LongestChain => Box::new(LongestChain::new(block_store.clone())),
     };
 
-    let spec = ChainSpec::foundation();
+    let spec = FoundationStateTypes::spec();
 
-    let mut state_builder =
+    let mut state_builder: TestingBeaconStateBuilder<FoundationStateTypes> =
         TestingBeaconStateBuilder::from_single_keypair(num_validators, &Keypair::random(), &spec);
     state_builder.build_caches(&spec).unwrap();
     let (state, _keypairs) = state_builder.build();