I would probably do the same thing and look for a plug that I could gap at 45 instead of 60, like was said before why put that much strain on the secondary system even though the HEI could take the 60 gap I would use the NGK they work very well I use them for both nitrous and straight engine running You will really have to see what the engine likes, it may want the colder plug with todays gas.
I like to use the coldest plug (especially with ethanol fuel) that will not foul and yes an improved ignition like HEI or MSD (vs points) helps make that possible.
Yes, use the coldest plug that will not foul. The correct plug for the OP is a 44 in AC Delco heat range, so he chose an R44TS, and an NGK UR-55. Those are good choices. The NGK plug is more like an R43 heat range. The UR4 would approximate an R45 or 46. The only problem is that the UR-55 is meant to be gapped at .060. If you close it down to .040, the ground electrode will be less than perpendicular to the center electrode and that is undesirable. If you want a gap of .040-.045, you would be better off with the UR-5. NGK doesn't recommend changing the plug gap by more than .008. http://www.ngksparkplugs.ca/tech-info-spark-plug-faq.cfm#sp16
It mean that R44TS's were never meant to be gapped at .060" which is what the factory spec is for a 455 with HEI. That's why they made a TSX plug for isn't it? I can only think your being intentionally obtuse with me Schurkey, I have to say your a real hair splitter. Thanks, I actually regret posting on this thread.
It is ok Jason I read all the information posted. There is always some rubbish there is always plenty to learn. None of which is wasted I appreciate all the posts, there is vast amount of experience out there to glean all sorts of interesting ideas and knowledge from. Our fuel in NZ is different as well. Compression I was told was around 9:1 after the heads were machined. I noticed as the compression came down during the 70's that the plug heat went up. I thought I would have a dollar each way and cover the general area it could be in. I am now confident I have done the right thing. Thanks guys. Will follow up with the results.
The issue is that you started-out recommending a plug that's two heat ranges hotter than what's working for him as-is, and designed for a gap that's way too huge for a vehicle that's likely to be driven hard, at least some times, based on the aftermarket intake 'n' carb, and suspension products installed--not to mention the Crazy Old Man behind the wheel. And you're doing this based on his distributor, (aftermarket HEI) while ignoring all the other parts of the engine that DON'T correlate to an emissions-lean, pellet-converter-choked, EGR-polluted vehicle that your recommended plugs are intended for. He didn't start denying performance ambitions until after you'd made your recommendation. (and even then he's leaving the door open: "for now", "Miss Bessie will get some mods" and "the car is next".) I would like to make sure this guy doesn't hole a piston. It's not good practice to Test and Tune starting with hot plugs, and move colder if you make a lot of smoke. Start colder, go hotter if they foul--or--keep using what's working already. And now, having gotten Huge Gap Fever, Larry's got to calm him down 'cause he wants to spread the ground electrodes of the plugs he did buy--which thankfully are likely to be a workable heat range. The R44TS at .040 or .045 are likely to work very well for him, even though they're "not meant for HEI".
I started out by recommending a factory plug and a factory gap rating for a 455 with HEI. The engineers at Buick evidentially had "gap fever", not me. But what the hell do they know right? Welcome to my ignore list....
The AC RxxTS6 and (same as RxxTSX both should come out of the box with a .060 gap) and even TS8 (yep .080 factory gap) plugs were common on low compression/low reving smogger engines from the late 70s into the 80s. I don't believe the HEI has a lot to do with the proper heat range of the plug needed although the "hotter" spark VS the old points type with external coil might make it a bit more forgiving. The HEI is a must if you want to have any shot of jumping an .080in gap though! Seems like most stock type engines run on a 45 or 44 heat range plug. If you are sucking oil then a 46 MAY help but is not the real solution, only a crutch. AC plugs used to be the easiest to decode R Resistor 43-46 typical heat range (seems like there were some 42 and 47s available in certain configurations) T Tapered seat 5/8 hex drive. (No T then it's a 13/16 gasket seat) S Extended tip. (piston clearance allowing extended tip plugs were almost always the way to go) X,6,8 indicated increased factory gap on the side electrode. Seems like Taper seat plugs were .045 as default while gasket seat plugs were .035 but its been about 30 years since I knew all these codes by heart. There were some other codes that could be put in there for long reach plugs and other special apps but for 90% of the GM passenger car V6 and V8 engines from the 60s,70s and 80s the handful of codes above will decode most of what you are looking for.
Stopped running them after I had a hard time extracting a few after being in motor for years. Carbon buildup on the exposed threads I suppose or heat tweaked the threads some.....
Have fitted AC 44TS , finally have got rid of annoying ping, have been able to run another 4 degrees static. Static now 8 degrees with 22 degrees mech for total of 30 That is better than before and closer to the ideal total 32 , but on our 91 RON fuel that is pretty good. I can put 95 RON in if I want to get serious. But at $8.77 a gallon of gas.......
You could go back to the LTS plugs but go with colder 42s. I guarantee it will run better and make 8-10 more ponies
