My 305 is a 350

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64nailhead

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Dec 1, 2014
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Hey, those two plugs aren't interchangeable, or I should say you need to use the plug of correct 'reach'.
 
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Clone TIE Pilot

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Aug 14, 2011
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For intake manifold gaskets I like to use embossed shim gaskets rather than fiber ones as they resist being sucked in better.
 
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American Muscle 79

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Jan 29, 2018
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Hey, those two plugs aren't interchangeable, or I should say you need to use the plug of correct 'reach'.
Right you are, my friend. The plugs I had were for the straight plug 305 heads. I thought I could just throw them on these angle plug heads without thinking that the angle would affect the reach of the plug. When I had issues firing it up, I checked the manufacturer's recommendations and these longer plugs were what was suggested.
 

CopperNick

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Feb 20, 2018
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AC/Delco plugs have been my go to's for a long while so got to know them fairly well. The base plug for your 350 was probably an RTS 44. That is a plug with a recessed electrode. One range hotter would the the RTS 45. What I elected to run was the RTX 45 which is the extended electrode. The diff is that, sitting side by side for comparison, the electrode on the X-45 extends out farther. This exposes it to the air/fuel mixture more completely so the combustion burn initiates faster. The S-44 was pretty much what I'd call a smog plug due to it being less exposed in terms of how far it placed its electrode into the combustion chamber.

For most of the street engines I have ever had I chose to fit them with the RTX-45 simply because it was a hotter plug and both tended not to load up as badly when having to deal with stop and go commuter b*s* plus fired better in cold weather. That made the time between plug changes longer and reduced the amount of invective generated due to having to deal with 7, and 8, particularly when there was an A/C box in the road.



Nick
 
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American Muscle 79

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Jan 29, 2018
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Oh boy. I forgot to update this thread after I figured out my issue, so here's a quick update:

I was able to fire up the El Camino after dropping in the new gaskets and changing the plugs. As it did before, the RPM ran up to about 2000. With some help from my Dad, we found that the fast idle on the carb needed to be dialed back. After that, the car ran and idled without an issue.

However, there were some issues with the engine sputtering and surging when accelerating, even mild acceleration. I played a lot with the timing and idle mixture and determined that it might either be the distributor, the high rise single plane intake, or both. Instead of wasting more time, I ordered a pretty cheap 65K HEI distributor($65) so I could replace the older one I was reusing. I also started researching which intake might mate up to my heads well, which is when I realized that my heads have a conventional and a vortec bolt pattern. After doing a little more research, I found that most peoople had more success sealing properly when using a vortec. I also ended up going with a dual plane that would match the characteristics of the mild cam a little better.

After buttoning everything up, the El Camino ran spectacularly. I finished wiring the dual electric fans and have been daily driving it since with no issues. It really gets up and goes now! Anyway. I serviced the rear end since then and plan on taking it to the 1/8 mile out here to have a little fun with it.

I'll update then!
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