A guy on xrtwo.com, who put the XR3i MFI engine into his MK1 Fiesta used blue silicone tape to wrap this part. Must have been this "stretch&seal" tape:

http://www.samcosport.com/uk/rp_stre..._seal_tape.asp

IIRC he cut the fins down to give it a smoother look. Pictures of his build thread are down, but it looked quite well.