<p>Get them online from any foamboard suppliers with accurate thickness and length required. There are huge options for 4*8 boards.<br>
Visit Foamboardsource, Amazon, Foam Supplier, Creative side etc.</p>
<p>Such larger dimensions you can also get it survey at http://www.foamboardsource.com/foam-board--acid-free-foam-board--acid-free-foam-board.html. Really a acid free nature board with accurate rigid and heavy duty to perform.</p>
<p>You may have look at Foamboardsource, quality foamboards suppliers and usually deals in huge dimensional products of various types. Go for foamcore sheets available in 4*8 dimensions available in durable and rigid quality.</p>
<p>Hey! you can refer Foamboardsource online foamboard store. They offers huge variety and sizes of foamboards at affordable prices. You will definitely get a good deal there. You can learn from this blog<br>
http://blog.foamboardsource.com/2014/08/white-foam-board-inexpensive-way-to-add.html</p>
<p>Hi! i know one of the foam board store where you can get multiple range of foamboards .Hope your need will be fulfilled there ,you can try http://www.foamboardsource.com/foam-board--foam-board-with-memory.html .</p>