Isn't the normal max rpm of the flathead around 3600? Is there a way I can increase that to around 6000? What is holding the flathead back, is it just the breathing? It may sound crazy but I will appreciate any opinions/facts on this.

 

That is most likely the rpm @ peak HP not redline.

 

[updated:LAST EDITED ON 04-Nov-02 AT 05:51 PM (EST)]Ok, so is it around 4200rpm? I'm thinking about replacing an engine that sees 4000rpm regularly and maxes at 70000rpm.

I'm looking at an 8BA 239 block. I would put on a girdle for the main caps, of course the full flow oiling, keep the compression about the same for the higher spinning, and an electronic ignition. Probribly go with a 390cmf quad, or adapt a holley 2300.