Yes, I meant 275D as it appears in the Post Subject ... typing too fast in the reply

. As for what JWT considers high boost, anything over 20lbs; I think the sprockets would be well worth it though if not just for the tunability benefits.
Some of the issues I had with building the engine included not compensating for the bigger lift of the new cams before assembling the engine and installing it. Come to find out that the valves were hitting the piston tops and had to disassemble everything and have valve reliefs cut into the pistons (this was my stupidity, and an oversight). The second setback (other than time down waiting on the machine shop and my work schedule) was the 1st gen Cometic head gasket not sealing right and oil spitting out of the front. Replaced it with the high boost version from Cometic and used some high temp gasket splooge, no problem. Lots of other small issues but none that couldn't be overcome easily.