1969 350/350 R45S plugs ?

[Lawrence M.]

Searching through the archives I see some say these will clear the pistons other say they might not. Here is what I have for my engine specs. The numbers pad looks very good so I do not think the block has been decked. The pistons are TRW L2304 .030 . The spec sheet I got on the heads from the pevious owner says the heads are 186 casting with 1.6/2.02 valves and they have been CBN surfaced .010. I bought a set of AC R45S plugs and the reach does look a lot deeper than the AC R44 plugs I took out. Will these AC R45S plugs be safe to use in my engine or should I get a set of AC R45 plugs just to be safe? Plugs are cheap, pistons not so much.

Larry

[Duke W.]

Re: 1969 350/350 R45S plugs ?

An otherwise production machined engine with .010" off the head is probably not going to be a problem with the 45S if an OE thickness head gasket it used. You can measure it with a feeler gage inserted in the corners of the engine.

Of course, the R45 will certainly not be an issue and the R45S offers barely perceptable improved combustion efficiency and fouling resistance.

Duke

[Lawrence M.]

Re: 1969 350/350 R45S plugs ?

Duke,

Thanks for the quick reply. I think with the improvement of the S plug being so small, I'll go the safe route and install R45 plugs. Thanks again for all your help and advice here on the Tech Board. It is greatly appreciated and I have been learning alot as I search the archives.

Larry

[Clem Z.]

Re: 1969 350/350 R45S plugs ?

index the plug so the ground electrode weld point is in the area of 8:00 o' clock and 4:00 o'clock and you will have no problem with contact with the piston

[Lawrence M.]

Re: 1969 350/350 R45S plugs ?

Thanks Clem that is good info to know. I can see how indexing the plugs like that would give a bit more clearance on these L2304 pistons. Always learning new things from the people on this board.

Larry