I am going to start building a 358 with vortec heads and i wanna use the comp xm270hr cam. I have stock manifolds with 3 inch plates and stock risers .and side exit throuh hull thats 4 inch all the way. Has anyone had any reversion problems with this cam . I belive the 3 inch riser plates will help immensely to prevent it . Comp says i shouldn't have an issue . Looking for input

I run a Crower roller cam that's a bit bigger with no issues. If using Vortec heads have them set up for lift clearance as mentioned above.

i run xm270hr with no issues mercruiser manifolds and risers thru hulls i used valve springs from Alex's parts