I have these expandable beasts for $19 each and they come with the seals for
both ends.  I wouldn't replace a pushrod tube without getting the seals too
(if it leaks you are going to have to pull the whole thing back apart to
replace those seals).  I have used these several times with excellent
results.  If they weren't twice the price of the normal ones I'd use them
instead when I put an engine back together.

Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
Fax:     (856)-327-2242