RPM limit

Discussion in 'Small Block Tech' started by Swagon, Jul 15, 2019.

  1. Jim Blackwood

    Jim Blackwood Well-Known Member

    Like Johnny, I'm a fan of high speed engines. Love the sound of a strong V8 winding to 7K! Over carbing it seems to be one of the keys. Sorta bad for mileage and off-idle but just a matter of priorities really. With a blower you can definitely get there.

    Jim
     
  2. gsjohnny1

    gsjohnny1 Well-Known Member

    The question is where should you shift ?
    when I first did the s/p, it surprised the hell out of me that it went right to 7500 with ease. then shifted and rpm loss was minimal and would go right back to 7500. because I crashed that day, we never really went and tuned it like it should have been done. putz around with it and then the dragster came.
    one thing that is a game changer that nobody other than us has done is go to headers over 2"(forget if they were 2 1/8 or 2 1/4). we had the chevy headers modified to fit the 350. terrible, horrendous resonance inside the car.
    guy is right about the rpm when the engine comes alive. go below and you lose the race every time.

    but het, what do I know...……..i'm only guessing
     
  3. Fox's Den

    Fox's Den 355Xrs

    And if you saw those dyno numbers from the head posting the peak TQ comes in at where... over 4 grand peak at 4900
     
  4. Jim Blackwood

    Jim Blackwood Well-Known Member

    Good headers seem to be a big deal on these engines. In MGBs you rarely see anything but a shortie of some sort. Those ain't headers, they're a tubular manifold. I spent 80 hours building a set of long tube headers of equal length within 1/8" under the guidance of Ed Henneman back when I first put the 215 in the car, that and a 650 Holley really woke that engine up. About 240hp which is very good for a N/A 215. Eventually all those trips to 7K cracked a piston though. By conventional standards the tube size was kinda big at 1-5/8", more suited to a 300 or 350 which was a planned upgrade for the future. But it's consistent with Johnny's results. With the 340 now in the car I've been fighting valve float but so far the headers seem to work pretty well. Won't know until later just how good that really is. My guess? They could stand to be bigger. But there's no room for that.

    Jim
     

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