I was just curious what is the highest RPM that anybody has ever turned and still made power with a tuned port? The only stock parts im planning on using are the lower and upper plenum and they will be ported. Would appreciate any answers you might have thanks.

 

I fully ported (full length - not siamesed) the stock base and plenum and hogged out a set of SLPs best I could without cutting and welding. It would run the same ETs shifting at 5300 as it would at 5700, but ET and power dropped off REALLY fast past that point. You want to build around the shift recovery point with these TPIs to make sure you're catching some of the torque boost from the runners when you shift into 2nd gear. You have to run a decent set of heads, a good exhaust system, and a cam with at least 218 intake duration to do that.

 

My 1-2 shift was around 5,850-5,900 on the STOCK runners and plenum feeding my 350 TPI Vortec in my Van. The power was definately still hanging in there at 6K as it would pull right up to redline and actually bang off the rev-limiter for a second or so before the trans could complete the shift. 2-3 happened around 5,500, STUPID SLIPPING 700r4 was on its LAST leg. I raised the rev-limit to 6,500 in the ECM and just let the transmission slip during the shifts. The transmission DIED shortly after that, but the TPI didn't mind reving out to 6,250 before the 700r4 could catch 2nd.



Rebuilt 4L60E with Transgo HD2 shift kit and stock converter.. 1-2 and 2-3 upshifts right at 5,500 in the PCM programming. Nice tight shifts.