RPM limit of 347 stock block and sportsman

Given a steel reciprocating assembly and atmostpheric aspiration (don't say normally aspirated anymore!) how high would people regularly rev a 347 street motor without a stud girdle?

Anybody got any practical experience of this one?

I don't have a girdle on mine, I think they are a heavy worthless POS. Anyway I shift my 347 ~6800 in a 289 block. A good balance job goes a long way. At last count there were just over 80 passes on it, no issues.


todd
www.home.earthlink.net/~tbeaudoin

Myoldisbroke ,

Very impressive ride you have there , does it see any street miles? What does it pull from , wheres the torque peak? Looks like it carrys the fronts.

Does your 68 block have the full width mains caps like the hipo and 74 mexican block I have.

A lot of people have been slagging off 347's , whilst I concede the 3.25 strokers have some advantages with ring placement etc I was interested in block strength which is exactly what you told me about. There is not room for a 351 in my Cortina , had to cut everything to get the 302 in.

It seen some street miles when it was first put together, later it was put on trailer.

If I remember correctly the block's caps are the same as a 302 just a bit thicker, its also supposed to be thicker in the lifter valley area where they tend to split.

When the motor was pretty fresh and trapping 124mph it laid down 410/470 to the tires. But I don't consider those # to real due to the high stall speed and the slicks spinning on the dyno. Cam motion did an awesome job on the flat tappet in it, pulls like a bear from idle to 7K.

I had fears on the 347 at first, my builder talked me into the 347 over the 331. I'm happy!

todd

If you get qood quality parts and have it balanced I don't think you can go wrong with either a 331 or 347 now days