So how is the progress going? I too would like to build the T-51 with Chevy power. Just does not seem right to put a Japanese motor on an American warbird! But it seems there is a lot of paranoia at the T-51 Builders' website when you mention anything outside the box, though. Especially Chevy V6's! So be careful who you talk to about this, lest you get harassing phone calls like I did.My 2 cents worth. I'm planning on an aluminum block 4.3 on my Titan T-51, but first talked to Jess Meyers of Belted Air Power, got a list of customers and called about 7 of them, all reports were encouraging. All had accumulated about 200 hours and the only engine related problem was one had a crankshaft failure early on, replaced it and had no problems after that. These engine/redrives have been flying about 15 years or more.