boondocker

I'm in the process of rebuilding my '72 350, will be reboring 30 over and wanted to go with a smaller dish piston to boost my compression high enough to run regular octane while increasing performance. Any spec/manuf suggestions?

...also have a XE262H, heads are done (3 angle etc...)

boondocker

I found a cast iron piston from Mondello 11.9cc with 7a heads should be 9:14:1...is this regular octane friendly?

http://www.mondellotwister.com/PisPinRingBrng.htm

cutlassefi

Cast iron?
9.14 is pump gas friendly.

boondocker

Thanks, 87 octane?
"Cast Iron" is what Mondello refers too...is this the rings?

cutlassefi

Should be Cast Aluminum pistons with Cast iron rings.
Imo you can do better for not a lot more money
http://webcache.googleusercontent.co...istons&ct=clnk
Use a moly ring if possible, not that much more.

Jmo.

Btw 89 octane, maybe, depending on the cam and gear.

boondocker

I'm looking at a TRW piston set (NOS) with the following specs;

TRW L 2389F .040 OVERSIZE FORGED PISTONS AND ONE SET OF TRW T 8190X OVERSIZE CAST PISTON RINGS
2.932" X .235" DEEP CUP,1.610" COMPRESSION DISTANCE AND A .980" DIAMETER PIN.RINGLANDS ARE FOR 5/64",5/64",3/16" RINGS

Are these slightly higher compression than stock (stock 2.920/0.215 dish and compression distance is 1.595)?
.040 is mentioned is this non standard (.030)?

Thanks for all the advice

MDchanic

2.932" x 0.235" looks to be 26cc, which is quite deep.

- Eric

boondocker

I'm not sure if the larger compression distance (between wrist center and piston top) would bring it closer to the head giving more compression. It looks to be a pretty low compression piston in any case...

MDchanic

If you calculate the volume displaced by the 41.49 square cm of the "ring" around the dish and the 0.015" higher that the crown should sit with the different height, you get a 1.58cc decrease in combustion chamber volume, which seems insignificant in comparison to the 12cc increase in combustion chamber volume due to the increase in dish volume from 14cc to 22cc.

- Eric