Right, it'd need to be a 1/2" reach with the washer and an extended electrode. I'm not that familiar with NGK numbers though. Jim
Not sure on the part number I had used a cross reference chart to match what I wanted. The YR5 I think is a match for the R43 plug in a stock 1970 motor. This plug seems to work well on just the motor without the nitrous. Probably because my comp is at 10.6. If I had a more stock motor with lower comp I may use the UR5 which has more extension on the plug. The UR5 plug seems to be a good plug for most motors. If I was to run the HEI system I would use the plug that matches the R43 TS, plug as this one uses a .045 gap. With the TSX plug and .060 gap when that plug wears some you are now asking the coil to fire that worn out .060 gap and may be hard to do and will start to wear on the plug wires as the electric will find the path of least resistance, plus this large gap starts to beat on the coil. Why make it do more than it needs to.
NGK 6222 seems to fit the 1964 300. It has a 12.7mm reach, about 1/2”. https://www.rockauto.com/en/catalog...9l+300cid+v8,1319510,ignition,spark+plug,7212
Which appears to be BPR5HS under the old number system. Not sure what the B, P, H, and S stand for. Pretty sure the R is resistor type and 5 is the heat range. Of course the new number, 6222, tells you jack about the plug. Not sure how this is better. Jim
B is 14mm X 13/16, P is projected nose plug, R is resistor, 5 is the heat range, H is 12.7mm (1/2") reach, and S is flat seat/ gasket. That plug is everything the FR-5 is except it doesn't have the v cut electrodes. https://www.ngk.com/product.aspx?zpid=9473 https://www.sparkplugs.com/Data/uploads/Charts/NGK_Plug_Chart_1.jpg NGK has 2 part numbers for a plug, the FR-5 is part number 7373
Actually I think the BPR5HS is the plug I'm currently running, and I think I did order them from Rock Auto. I think you just delete the "R" for non-resistor plugs IIRC, so BP5HS. The FR-5 also has 3/4" of thread so it isn't a viable substitute for the aluminum heads, though it looks good otherwise. Does it use yet another numbering system, or can you just swap in the designations and end up with something like FR5HS, F5HS, FPR5HS or even FP5HS? I'm uncertain if the split tip and extended reach are both part of the "F" designation or are separate. Jim
It is for the TA heads, just not for the aluminum 300 heads. The 300 heads just require the shorter reach plug. Not that I am aware of. Both the FR-5 and the plug you are using are of projected nose design. The V-Power plugs have a V cut into the electrodes. https://www.ngk.com/data/default/images/watermarked/450/NGK7373_d.jpg. I'm thinking sparks like to jump from one sharp edge to another.
That's not to say they've never been inspected for erosion, gap confirmed or adjusted, reinstalled. I do that about once a decade. I might have even taken them from my original engine (sitting on the stand) and put them in the new engine that has had a restore from the bone yard and a subsequent near-catastrophic thrust bearing failure. They've been around!
OK, so I went to the NGK site and the only two plugs they lost for the 350 are the UR4 #6330 V Power and the UR4GP #2869. They don’t list any UR5’s???
That is because the UR-4 crosses over to the R45TS which is the stock plug. The UR-5 is one step colder but the fit is the same. It is always best to use the coldest plug that doesn’t foul. The UR-5 approximates an R43TS. Is your engine bone stock as it came from the factory? If so, use the UR-4.
Larry- catching up on an old thread. So I have a 71' 455 with Iron heads and distrubutor+coil in my 72 lark shell. Was thinking of a changing the plugs since I am the new owner and don't know when it was done last. What ones would I get? These ? https://www.oreillyauto.com/detail/.../4537699/1971/buick/gs-455?q=Spark+Plug&pos=3
Just looked @ #1 plug (R45TSX), gapped @ .060 Can't believe how clean they look after 625 miles. 11.17 comp, @ 38* total timing.
