diff --git a/src/headparse.rs b/src/headparse.rs
index 94911b4..c5ca663 100644
--- a/src/headparse.rs
+++ b/src/headparse.rs
@@ -11,7 +11,7 @@ use crate::SignalFormat;
 struct Record {
     name: String,
     seg_num: Option<u64>,
-    signal_count: u64,
+    signal_count: usize,
     sampling_freq: u64,
     counter_freq: Option<u64>,
     base_counter_val: Option<u64>,
@@ -33,7 +33,7 @@ impl Record {
         }
         let name = args[0].to_string();
         let seg_num: Option<u64>;
-        let sig_count: u64;
+        let sig_count: usize;
         let sampling_freq: u64;
         // Everything else is initialized with None, this is for sake of me not getting a stroke
         let mut counter_freq: Option<u64> = None;
@@ -59,7 +59,7 @@ impl Record {
             } else {
                 seg_num = None;
             }
-            match seg_sig[0].parse::<u64>() {
+            match seg_sig[0].parse::<usize>() {
                 Ok(value) => {
                     sig_count = value;
                 }
@@ -406,10 +406,13 @@ impl Header {
         Header { record: None, signal_specs: vec![] }
     }
 
-    /// Creates a Header from a supplied Record struct. Initializes the
-    /// signal_specs vector
+    /// Creates a Header from a supplied Record struct. 
+    /// 
+    /// Initializes the signal_specs vector with the correct capacity provided
+    /// by the record.
     fn from_record(record: Record) -> Header {
-        Header { record: Some(record), signal_specs: vec![] }
+        let capacity = record.signal_count;
+        Header { record: Some(record), signal_specs: Vec::with_capacity(capacity) }
     }
 
     fn add_signal_spec(&mut self, spec: SignalSpec) {
@@ -432,8 +435,8 @@ pub fn parse_header(header_data: &str) -> Result<Header, &str> {
     let header_lines: Vec<&str> = header_data.split("\n").collect();
     let mut found_record: bool = false;
     let mut header: Header = Header::new();
-    let mut specs_read: u64 = 0;
-    let mut specs_max: u64 = 0;
+    let mut specs_read: usize = 0;
+    let mut specs_max: usize = 0;
     for line in header_lines {
         // Ignore commented lines
         if line.starts_with("#") {