Don't know anything about 700r4's but I've got Hedman 69830's in my truck and they fit great. There are a couple of pics here -
http://67-72chevytrucks.com/vboard/s...=217490&page=4
Actually the biggest problem I had was the header ports are kinda rectangular with curved ends and my heads were square port and I couldn't find a gasket to suit. Ended up using Copper Permatex RTV. Haven't run it yet to see if it worked!
One of my buddies lives South of Creston. Drove the skyway in March 05 in a rented GMC heading west to the Okanagen. Great place/country you got there.
Bill.