[1svtfan]

I cap mine at 6,500 for stage 1, and 6750 for stage 2. Internal 347

[olddog]

With most engines, the rods and oiling usually is the main consideration on where to limit the RPM, but the 5.0 block is its week link. I have seen pictures of several blocks that cracked from the main to the cam bearings. One block, when they unbolted the intake and main caps, fell in two pieces. I have heard it argued that power has to be limited. Others say it is RPM that must be limited. You can add girdles, but I never heard how much that helps.

Internal balance has to help. My 347 is external balance. I try to stay under 6000 rpm but I have hit the rev limiter a couple times on a stock A9L box. By my tach that was 6500 rpm, but as I go through the tune (just learning) it looks like a stock A9L is set to 7000 rpm. Correct?

If you had an aftermarket block, internal balance good crank, good rods and bolts, I would think you could spin 8000 all day long, likely more. With a factory block, I'm a coward. I would stay under 6000, if I wanted it to last. Just the gut feel I get from reading and talking with a couple builders.

[StangD]

Woody from Fordstrokers has a lot of PICs of stroker failure. He did my machinework. He told me detonation is what kills 347s most often. The main caps walk and it's all over soon. I also have a 347 in an SN95 stang. 28oz external balance. Still pretty fresh but I have had it down the track a dozen times or so. 12.1 @ 120mph so the potential is there if I learn how to drive it. As you said they rev fast with the right cam, valve hardware and induction. I can hardly shift it fast enough to keep from over revving it in 1st and 2nd.

To answer your question, I try to shift at 6200 even though I am still in my powerband. Very frequently it results in an actual shift at 6500. About the third pass I was scrolling through a datalog and saw I hit 7200 during a pass Not cool at all. I got my rev limiter back down where it belongs now.