Yenko Copo records question

[ace4]

hi im knew here, bear with me please I have a 68&69 vette both of them have yenko markings at more than one place. the 68 has a front clip that looks just like one of the original race cars its a bb aii #s are ground off block even date code only #s are casting #s 3855961 but after looking the whole engine over I found all kinds of sYc & copo markings along with #s behind the starter its set up to look at threw a mirror from above. the markings are mostly cast in block, at one spot you see what looks an arm pointing up when you adjust mirror to look up you see #s that say 427-425 could this be a 427-425hp iron head that yenko bought that weren't supposed to be in street cars, lot more to story reply here or email @ [email protected]