Re: IML: 1967 440 and trans {big valve heads}

["Bob" <impparts@xxxxxxxxx>]

THANKS for the info. 

I was going by word of mouth.  Glad theres people out there who know their stuff. I learned something today. I always enjoy reading info like that. Helps for future refrence. Thanks for the effort.

Bob H

----- Original Message -----

From: David Whitney

To: mailing-list@xxxxxxxxxxxxxxxx

Sent: Thursday, February 21, 2008 7:20 PM

Subject: Re: IML: 1967 440 and trans {big valve heads}

915 heads don't do an Imperial owner any good except for bragging rights, and the pain may not be worth it.  We're talking about a compression ratio greater than 10:1, requiring great care to avoid preignition and/or detonation with today's pig slop gasoline.  In addition, the larger valve sizes are of negligible benefit at an Imperial's normal RPM range (below 4000).  Even racers know the 915 heads don't flow as well at high RPM as the later heads that came with larger valves.  This engine combo is best suited for somebody trying to do a correct restoration of a car that came with it from the factory.  Those of us who like to drive our cars a lot need later open-chamber heads.  Compression ratio is lower, the valves are larger -- paint them Mopar turquoise and only an expert can tell from the outside that they're not year correct for your car.

 

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