substitution parts

[Stephen B.]

would these pistons(h618cp) be a reasonable replacement for 3942545 pistons in a 350/350

[Duke W.]

Re: substitution parts

The OE replacement L2304F dome volume is 2.4 cc, but the H618CP is 3.5, so you would likey have to use a thick head gasket to keep the compression ratio within the target range of 10-10.5:1, true. Also, it does not appear to be available in oversizes.

http://www.fme-cat.com/overlays/part-detail.aspx?pNum=H618CP&partType=Cast%20Piston&brandId=SD

As built by Flint the CR was closer to 10.5 than the advertised 11:1, and the engine should operate on modern unleaded premium without detonation at up to 10.5, true. The biggest variable is deck height/clearance, so deck clearance should be measured before disassembling the block so you can get a handle on managing compression ratio.

You should maintain something near the original dome volume (say zero to 2.5 cc) to achieve the desired 10-10.5 true compression ratio for a L-46 assuming you use an exact replacement camshaft, which I highly recommend.

The Keith Black SKB 119 would be a good choice with a thin head gasket to achieve the target true compression ratio range. It has a net "dome volume" of -0.5cc. Note that Keith Black lists net "domes" as a negative number since it subtracts from chamber volume, but this is opposite industry convention, which usually list net "domes" as a postive number and the value is usually entered into compression ratio calculators as a postive number. Be very careful about observing correct sign convention.

https://www.uempistons.com/index.php?main_page=product_piston_info&cPath=3_4_24&products_id=3107&zenid=f12e14ac48c4347598067db1276df5d5

Duke

[Stephen B.]

Re: substitution parts

thank you duke