4 spd dust cover

hello,I have a 4 spd dust cover I bought I was told it was for a small block but it does not fit my bellhousing.looking at other pictures it looks like a big block cover but not sure.it measures 15.5 at the wide end and 10.5 at the short.you guys probably know more than me what it fits.im asking 20.00 plus the shipping.thanks