pre-xflow/x-flow pistons

[2nd.gunman]

are these interchangeable? as 250 to 250, 200 to 200

 

[xctasy]

The only difference is the dome. The log heads (All 188, 200, 221's and early Oz 250's) were about 6.5 cc small dish 2" domes. The later polyspheric head found on X-flows needed a 15.5, 22, or 28 cc 3.5" dome to get the compression down.

The 200 x-flow was smallest, then the 250 XC/XD/XE was next up, then they when to the 28 cc item for the last of the XF's when unleaded fuel was introduced.

If you use the right combination, you can make an early XE or XF head come up to 60 cc with a little work, and then an early 188/200/221/250 piston will work.

There is also the US made Silverlite flat-top 1.50 or 1.53" tall HSC 2.3, and 1.555 to 1.585" HSC 2.5 and 4.2 V8 piston which are dirt cheap and flat-top, but they have shown a tendancy to crack in a couple of instillations, and the last two are too tall to fit an X-flow without carefull checking of the piston to head clearance.