Piston talk...3500 style

[ForcedFirebird]

I believe what GM meant by comparison is the tall roof on the intake port of the 3900 which is higher than on previous heads. Unfortunately the valves are shorter on the LS1 heads so they are not candidates for swapping into the V6 head. I'm still interested in a combination offset crank and 4" bore on my extra block though. I'm still amazed at how Fiero members are still favoring naturally aspirated iron head V6 motors over the aluminum head motors.

I got you now.


The Fbodies still seem to be stuborn on the iron heads as well. For fear of tuning (actually needind an ECM swap) in the 4th gens, they don't convert.

I would like to see the stroker, I remember you saying you found a place to do the offset grind - was that here in FL? You might persuade me on the next build.

[Ray Hamilton]

Would the 3.6 pistons work in a 2.8 with iron heads and a 3.1 crank and 2.8 rods?

[Joseph Upson]

I got you now.


The Fbodies still seem to be stuborn on the iron heads as well. For fear of tuning (actually needind an ECM swap) in the 4th gens, they don't convert.

I would like to see the stroker, I remember you saying you found a place to do the offset grind - was that here in FL? You might persuade me on the next build.

Flat lander racing is the link I found some time ago for offset grinding the crank however, my first search locally was a place in St. Pete that quoted me the same price for it $200 but didn't mention whether they could add metal for a greater stroke. If I do it I'll aim for a 4.3L displacement by doing a combination with over bore for the 350 pistons unless there is enough room to do it with the stroke alone. The small block 350 has enough room to go more than .25 over stock stroke and since GM said the 3900 was designed to allow future increase in displacement the space may already be there to allow that kind of increase or more. Going with the chevy 4" bore would give me a much wider piston choice.

Problem is I believe my stock motor will be capable of enough power to make the car frightning to drive, unfortunately the theory does nothing to satisfy the imagination, and then there are those magazine articles with production cars running sub 5 second 0-60, I believe that's the motivation for me to keep uping the power since I'm a 0-60 driver. I want my car to be quicker than 99% of what you can buy off the show room floor.

And yes those are 3900 heads in that photo back ground, you would have to see them close up to appreciate the port design.

[Joseph Upson]

Would the 3.6 pistons work in a 2.8 with iron heads and a 3.1 crank and 2.8 rods?

Not even close, it's much easier to buy an engine with nearly the displacement you want (3500) than to try and bore and stroke a smaller engine to a displcement that's already being produced which tends to be more expensive and a weaker product.