I have a 61 with a 235. The posts I've read on this site says a carter 2100s will work on this engine. But when I went to put it on, the bolt holes are wrong. The original Rochester holes are 2 15/16 OC and the Carters' are 2 11/16 OC. Did some 2100's come with different bases? I'm out a bit of money now if I can't make this work. Any suggestions would be appreciated.