[A Snake]

I'm unaware of Sidewinders being modified to fit CJ and LR heads as such, but the ports are ok. They look shorter, and are, but look at the bottom of the intake runners. They're higher and the top is in the same place.

What won't work at all is MR heads on a 428. Remember, a 428 is a big overbore from a 390. A 427 is a different block with a much larger bore. The MR valves are SPACED FARTHER APART and they're much larger. The valves will hit the top of your block on a 428 and as I am told, you can not cut enough relief for them to clear without hitting water.

I suggest having a well preped. set of CJ heads done and try the Sidewinder with that. I've done it and it worked very well. Do remember the long stroke of the 428 is not intended for the high rpm a 427 is. Unless you're just going to drag race, trying to make a 428 buzz like a 427 is a waste of time. It makes plenty of HP and torque up to about 5500rpm.....plenty enough to give you the ride of your life.

The police interceptor manifold was the same as the CJ and will work fine. It won't work as well "upstairs" as the Sidewinder, but hey, how much is enough.

One good thing is that the Sidewinder looks right under the hood.....with a pair of plain chrome valve covers, you can't tell the top end from a 427.