I have an 91 5.0 and I was thinking of putting in a B303 Cam (.480 Lift) with 1.7 Roller Rockers. That should put the total lift at or around .510 Total Lift. Will that much lift work with stock pistons. Duration is 224/224. ??? Thanks
90Mustang - did you measure? What was your clearance?
Eliaseje - p to v clearance isn't impacted by peak lift. Go to this link and read - it'll explain it. The issue in your case is the increased duration which opens the intake valve sooner and closes the exhaust valve later. As mentioned at the link, the tolerances are close, so the fact that someone else didn't have a problem doesn't mean that you will or won't have a problem. Every engine is different.
Ford Racing recommends that with 1.7's and the E cam or B cam, you should measure p to v to be certain. If I'm installing a new cam with earlier opening intake timing or later closing exhaust timing, or if heads are milled, blocks are decked, new heads/bigger valves are installed, different pistons are installed - I always measure p to v. Taking someone else's word doesn't mean a thing on your engine.
There are other issues. You didn't state what the rest of your mods are. But putting a B cam in an otherwise mostly stock engine will probably actually decrease your overall performance - almost certainly if your car is injected. If you've got the mods to support the cam (heads/intake/exhaust) then forget the comment.
.200" on both intake and exhaust? Identical clearance on both? Just trying to clarify - so many people post that they have no problems, and it often means that they didn't measure at all, they just haven't had any problems - yet. With the E, 1.7's and Y heads, I had .110" intake, .210" exhaust. My custom is much milder in terms of duration - so even larger clearance now.
512 lift and advanced 224 duration works with or as Mike says!! IF there any mods ... like he said heads milled ,Block decked , or a real thin head gasket.. then check it out!! But stock engine and bolt in!! esp. on the 91 5.0 !! Cool?? Hey.... you best NOT be at the Beach while we are FREEZING here on ConUS!! LOL OMG it is all of 46* here this morning.....( in Fl.)