04BlueGT

??? 475 and only 359 to the wheels? That is a 25% drive train loss. Did you mean 425?

avlon06

im assuming that a tune would be needed after a new shortblock or forged internals go in correct?

04BlueGT

Okay, Sxynerd, I did some very quick Internet searching and the answer is... yes and no.

According to How To Build Max Performance 4.6 Liter Ford Engines by Sean Hyland, both the 6- and 8-bolt cast cranks are safe up to 500. (I assume this is conservative.) Chapter two says the 8-bolt is preferable, but does not really state why. My guess is that 8 bolts are better than 6. Not exactly rocket science. Maybe the balance is a little better at high rpm due to that salient fact alone.

Sxynerd

I've done lots of "quick searches" ltoo, I've even spent a few afternoons calling around to different shops and thus far everyone can only regurgitate.

Haha, I hate that book. It tells you just enough information to want to know when the next book is supposed to come out to say everything the first one didn't. 500? hahahahah, yeah ok. Even the mmr600 is good till 600rw wheel and it has a cast crank. Almost every Mod builder shop knows that the cast crank is good for 600 or 7k.

Then there are some shops like Livernois that wont even touch a Cast cranks.

04BlueGT

I said it was quick. Between work, college and my son's cub scouts, I don't have time to research 4.6 crank potential. Probably the only way to get the 'true' numbers would be from a Ford engineer. I don't know any, so 600hp will have to do.

Howver, if I was already into the internals, I would go forged just for peace of mind. I would rather overbuild than not. More $$ for sure, but it opens other options further down the road.

grogan

idk..im just going by what jpc, my tuner, told me. he said 475 at the crank with 360 at the wheels