ok - so I'm jumping the boat and going twins.
I'm tired of fighting EGT towing even with methanol - dont want to go with reasons here - pm me if you need info on that one.
I am guesstimate around ~400HP right now. I doubt I will ever go over 500-550 due to mpg and breaking my tranny
So - I currently have a he351cw from john (AH64ID) here. Works well but want more. So underneath it as a primary will be a s472. My first step will be STUDS. This will be a longish thread. I am going to follow the ARP sequence and instructions for torque - you can get that here.
http://www.glacierdieselpower.com/images/PDFs/ARP%20Head%20Stud%20Installation.pdf
Likely to start in around 6-7 days after weekend Will be ordering twins shortly as lead time is around 3 weeks.