I have an opportunity to purchase some new GT40P heads for a 1966 289 that I am building. The block has been decked and has new flattop pistons for a CR of just under 9.5~1 with 60 cc heads. I was told (haven't been able to verify) that the GT40P heads won't work on an early 289 beacuse they are set up for a roller motor. I thought this didn't matter as I am using a flat tappet cam. Is their anything I am missing? I was planning on using 1.6 roller rockers and didn't know waht pushrod to use. I am going to use the Edelbrock Performer RPM cam (#7122)(.520 lift). I didn't know if the stock GT40P valve springs were suitable for this if I can indeed use the head. Anybody out there do this before? Brian