Measure for correct pushrods, new valve springs/locks/retainers if the heads are used?
Why are you putting new heads on a 94 Cobra? Stock ones went bad or something? They do not need new heads if the OEM ones are working fine. Easy to get to 275whp with the stockers and then just supercharge from there for more power and less money than a HCI.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.