R44 or R45S plugs??
 

Hi guys! My manual recommends R44 plugs for the 307 in my 69 C20. I'm running stock ignition with points. The parts store sold me R45S plugs for it. Is there any issue with that, or should I go back and get the 44? Thanks so much as always for your help!

Wes

Re: R44 or R45S plugs??
 

The R45s is a hotter plug. My 327 burns oil so I changed from the R44 to the R45s to help from fouling the plugs.

Re: R44 or R45S plugs??
 

It is hotter (as mentioned) and also comes with an extended tip ( S designation). What do the old ones look like? With todays crummy fuel I'd say stick with the 45s

Re: R44 or R45S plugs??
 

That's what I'm running in my 283

Re: R44 or R45S plugs??
 

I plan to pull them tonight and have a look at them. I have no idea what's in there and how old they are.

Re: R44 or R45S plugs??
 

The extended tip plug came out in the late 50's early 60's for o-head valve engines. All the manufactures soon went with them. They are a big improvement from the recessed tip plugs. The R45S plug is only one step hotter then the R44. That is the best way to go. They should not be used in flathead engines.

George

Re: R44 or R45S plugs??
 

Just checked and I put Autolite 85 plugs in my '69 307 last time . Was that a bad choice ? Seems to run ok . Thanks !

Re: R44 or R45S plugs??
 

I used those in my 350 and they were good plugs ,I may switch back next time in my 327,Im running the 44 in them now.

Re: R44 or R45S plugs??
 

The R45S's should be fine in the 69 307 heads. The older motors tend to lose compression and use a little more oil so going one number hotter is probably a good move. I run the same plug in my 427 BBC w/69 closed chamber heads...I found some ACDelco R45S plugs on ebay for a $1 a piece. They were NOS plugs made in the US, they're not anymore. Hard to find US made spark plugs these days and when you do find them they're hot cheap! I'm running Pulstar plugs in my bike... http://toms427impala.info/CT/ACPlugI...Extended%20Tip

Re: R44 or R45S plugs??
 

Interesting. Two of the plugs I got are made in the USA, two made in Mexico, and four made in China. Should I take them back and at least get all 8 from the same plant? If there's a significant variance, it seems like that could have a couple of cylinders running hotter than the others...

Re: R44 or R45S plugs??
 

Thanks , Kaycee !!

Re: R44 or R45S plugs??
 

Anyone have thoughts on mixing and matching the same model plug from different eras/plants? Seems like it would essentially be the same as mixing the same plug from different brands, which I know is not a good idea. Perhaps I should return them and buy a set of NOS off ebay?

Re: R44 or R45S plugs??
 

Pretty sure that the product manufactured on different continents is going to be different. Might have not been the case in years past, but now, who knows?

Re: R44 or R45S plugs??
 

I doubt the difference in manufacturing plant will make such a difference as to be worried. You are going to have a bigger variance in cylinder compression and oil consumption and old plug wire in each hole than you are spark plug difference.
The plugs are not likely going to affect a 100 mile plug read. I would use what you got. Look them over at 100 miles and go from there.

Re: R44 or R45S plugs??
 

I bought him out, he only had 26, I just tuned up the fleet...;) Different plugs wont hurt a thing. These late model electronic dudes have O2 sensors on every head pipe can probably see the difference, maybe? That charge and piston dont know what brand just set the fire...