Dished stock pistons?

SIIaCanuck · Oct 9, 2018

Has anyone ever machined a dish in a stock piston?

I'm doing a head swap and don't have the time to build up a new short block. The heads are ported GT40p with 56.5cc chambers. I have a low mileage stock short block that I'll throw them on. However, I'd like to stay under 9.5:1 compression due to a lack of premium gas around here.

Is it possible to turn a stock piston with the 5.5cc valve notches into a +10cc piston?

It might be just as cheap to get a set of KB Hyper +11cc pistons, but I thought I'd investigate.

evilcw311 · Oct 9, 2018

@OLD H2S this is a question for you I’d say.

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SIIaCanuck · Oct 9, 2018

Of course, I'm not saying that I'd get KB hypers if new pistons is the only option. I'd stick with forged.

The short block I've got has stock forged pistons in it ('89 spec pistons). It's these pistons I'm wondering if the crown is heavy enough to take a slight dish.

OLD H2S · Oct 10, 2018

I have done that, but the short answer is no. The parts get too thin to use, but you can recut a Ford piston to fit some Jap cars with just a little smaller piston but you must know how to cut a taper and what the taper is for that manufacturer. Here is the place I start when I look for pistons for a good overview of what I want, when I dig deeper into the company web sites.
http://www.modmaxracing.com/category-s/2.htm

SIIaCanuck · Oct 10, 2018

Thanks, that's about what I suspected. I'm going to have to do some careful investigating or this 'head swap' is going to become a rebuild, which I was hoping to delay.