will 1.7 rockers and stock cam make a noticable idle.

Yes it does make a noticable idle difference but minor.This I was told was because your duration increases slightly with the 1.7's vs.1.6''s due to the higher lift.Instead of stock's 204 @ .050 it might be at 206 degrees.No big deal.You will definately like the power increase with 1.7's if you go to after market heads.

DO NOT USE the 1986/E6 heads. They are junk; that is why they lastest one year. Go for the 85 heads or like you said, older. The alpha cams are not junk, but they are inferior to newer cams. The point is, they make power, just not as much as a newer cam in most cases, or a custom. I would recommend going with a TFS cam. They are the exact same as the ford cams, but they add duration on the exhaust side. This is important since Ford heads have always been weak on the exhaust side. The cams are about the same price. Your block is probably from an 85 GT, and it was originally a roller block with forged pistons, and it was carbureted. The torker II will get you hood clearance since it sits lower than a stock intake, and the 600 is the perfect sized card for you. Keep it under 650 and your golden. My 85's first combo was stock 86 block with crappy 86 heads, 1.6 rollers, Ecam, Performer RPM, and Road Demon 625, and full exhaust with dumps. Dont know the gear ratio, but it was the 7.5, and drag radials. She was very reliable and consistent, running 8.5s in the 1/8th, and 13.8s in the quarter all day. I almost prefer that setup over the big block now. With the little I did, 8.5s in the 1/8th is very respectable, and it was enough to beat most commers at Race Legal at Qualcomm back in the day when I was in the service in San Diego.