I had recently did a 5.0 swap in my uncle's Galaxie. After we finished it wouldn't start, so I finally switched to the non-HO firing order and it started right up. So we figured it was a non roller cam. But it never ran right, it always seemed like the timing was off, the engine had no power and almost a consistant back-fire. After a few posts on here I took a lot of people's advice and talked my uncle into doing the roller cam swap before we had the car finished. So as he was taken it apart to install the TFS stage 1 he noticed it had a spider in the valley and then after further disassembly we found roller lifters that should be there if theres a spider. At this point I was lost on how it was a roller motor but ran on a non-roller firing order. But as he took off the timing cover we seen that while the #1 was at tdc the crank gear alignment mark was pointing staright up like it should but the cam gear mark was also point straight up ( 180* the wrong way).
So when a roller cam is retarded or advance (whatever you want to call it) 180* it will idle nicely when on the non-HO firing order but run like crap (back-fire and no-power under a load). It did sound pretty good at idle and had received a few compliments from the people who heard it.
Has anyone seen this before or know why someone would do it? The guy we bought it from had never driven the motor, as it came out a car he parted out.
So when a roller cam is retarded or advance (whatever you want to call it) 180* it will idle nicely when on the non-HO firing order but run like crap (back-fire and no-power under a load). It did sound pretty good at idle and had received a few compliments from the people who heard it.
Has anyone seen this before or know why someone would do it? The guy we bought it from had never driven the motor, as it came out a car he parted out.
thats not the problem I guarentee you had it on TDC on the exhaust stroke ,that is what it would look like, also not all roller motors have the 351/302HO 137.....firing order either 
