Thread: 383 head change ??

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Pistons are flat tops w/valve reliefs. The Vortecs have been modified for more lift.

You may run into a problem with piston to valve clearance depends on lift and with the flat tops and 64cc chambers it will put you over 10.1 and more than likely lead to detonation. I used Dart Pro1 alu. heads 200cc runners ,72cc chambers on my 383 and my lift is .544/.520 270/276 dur. advertised. I do run premium and no problem runs hard and strong.

Dave

"I have to run 93-94 octane to keep it for detonating."

I'm guessing this is because you paid little or no attention to the squish. With a good tight squish of 0.035"-0.040", you could probably run a lesser grade of fuel without detonation. I'm further guessing that with Vortecs, this motor will rattle like a can of rocks if you don't adjust the squish. Just my opinion.

At the time that it was put together and because of the heads used Squish was not taken into enuff consideration. The heads are still going to be changed. I'm just tyring to figure out what direction with a tight bugdet