[Stan Weiss]

Originally Posted by hojs69

Old post from 2014 from Steve.

"My 577" is a '59 389 with a .315" over stock bore and stroked 1.050"! This was done around 20 years back in an effort to have the largest Pontiac ever. The problem with boring out the stock cylinders is that the deck is not strong enough to support it. I learned this from Ken Crocie, he had told me he had tried it years earlier and the decks lost so much strength, it would not work.

The way I made mine work was to use deck plates that raised the deck and added the support needed for integrity. I ordered custom extra long sleeves to accomplish this. Again, this was very expensive and time consuming and before the aftermarket blocks were available.

If you can access a boring bar to use as I did, you can try all sorts of things but, as others said, you are better off seeking a 400 block."

I know he showed pics and all but I cannot find it right now. Hopefully he weighs in. Ahead of his time here.

Originally Posted by Steve Barcak

Changing bore spacing makes no practical or economic sense and will not happen as a result. With that said, there should be a need for taller deck heights but, apparantely most builders aren't using the foresight to take advantage of better rod ratios with larger displacements.
I will predict that as more of the new parts are used and larger displacements are sought for more power, demand for a taller deck height block will follow. Most people now with larger engines are seemingly happy in the 530" range. As you go over 550" or so, the taller deck becomes more attractive and even necessary.
I have had a super tall deck 577" Pontiac project for years but, it has been put on the back burner since I decided to go the with small inch route with my AA/Fueler. However, the first one may be together in 2007.

My blown/injected 577s, based on early 389s, have deck heights of over a foot. One will be used in my '65 Tempest altered wheelbase funny car project and another in one of my boats.
Tall decks have advantages, esp with larger displacements.
What is the 'tall' deck height of the engine you are considering?
Stock height is in the 10.2..." area. My 577s" are around 12.200".
Running the taller height in the deck gives much more room for a better ring stack, allows longer rods, etc and is very attractive with longer strokes.
Steve Barcak www.pontiacheaven.org

"Real Pontiacs only...no corporate nonsense!"

WOW 2" increase.

Stan