I read my 66 Cutlass Assembly manual front to back. I found that ONLY 442's had the brake line for the right front wheel is routed in FRONT of the left engine mount while non 442s brake line went straight, behind the mount. My (unknown 66) has this brake like routed in front, two fuel lines, boxed rear control arms and its a F85 Deluxe. Now Im 90% sure my Fremont 66 IS a 442..However, there will never be a way document it..

 

4 speed or automatic?

 

This was a big topic on FB about that line being routed in front of the mount. The PIM shows it that way on 442 models but some of the experts had different opinions. In my experience,all of the 66 442's models had the line routed that way. I do not know the reason for that but I'm sure GM had a good reason.

 

Might have been to get the brake line way from the left exhaust down pipe.

 

While there is some small performance increase from shorter, more direct brake lines (and I do not know whether this new routing is such), the mass car market would probably not care. My thought is that something is in the way of the brake line in the other routing that is not there normally. Like Rund said, it may be the dual exhaust