The MOPAR’s 318 Part I

Before we start, I’d like the readers to know that these segments will not be an all-encompassing reference effort.  But I will have details that might not be well-known and some long forgotten.  Hopefully, it will be fun to read and informative.  The first few segments will be engines I’m familiar with.  I’ve owed a lot of cars and at least one of the Big 3 (Chevy, Ford, Chrysler) and all with different engines (and one with two).  First engine I am going to tackle is the 318.  I owned a Dodge Dart in the mid to last of 1970’s and it did have the 318 manual transmissions and at this very moment I can’t recall the other specs, but I’ll find them in this research. It that a great engine and simple to work on.

I’ve heard it mentioned that the 318 was Chryslers’ 350 (referring to GM’s 350, that’s been in existence for… just about forever…no it hasn’t but that’s another segment).  Of course the 318 didn’t have near the run that the 350 has, but it’s got some pretty interesting history of its own.

Let’s start with when the first 318 was used in a MOPAR car and what followed that up.  We’ll also look at some specs and some configurations it came in, you know carbs, cams and the like.

In the 1958 Plymouth the 230 c.i.d Powerflow Six was used as the standard engine, same as the previous year.  Chrysler did have V8s that were a possible option in 1957 and 1958, namely 301 and 277 cid.  However, it’s believed that the 318 was to replace the 277 c.i.d and the 301 V8s as the car maker moved toward try to capture a larger market.  The 318 had 9.25 to 1 compression ratio with 225 horses, it became the standard V8 used in the Plaza, Savoy, and Belvedere.  Perhaps the most powerful configuration you could get at the time was called the 318 Dual Fury (Sport Fury) V8 aka the Super-Pack rated at 290 horsepower; the dual was for the two  4 barrel carbs. The rest of the configuration included solid lifters, high performance cam, dual point distributor and dual exhausts.

The drive specs for the 1958 (which was a great looking car)

’58 Fury

 

shows that the standard block of for the Fury was the 318.  You could add the sport fury to it and go from 225 horses to displacing 350 cid and producing 305 hp, with 2 Carter, 4bbl carbs.  The nickname for the engine was the “Golden Commando” and it was paired up with TorqueFlite auto trans.

Oh, by the way 1958 Ply Fury was the star of the Stephen King book entitled “Christine” and later the  movie.

There is a lot of talk, even today about the Hemi, “Yo..dat got ah Hemi?”  It was a great design. But we won’t talk about the Hemi in this article, but we will mention the polyspheric cylinder head.  What is a ployspheric cylinder head?  That was a question asked by one of my frequent readers and this was my reply.

Poly is short for Polyspherical head. Some say it was a forerunner to the Hemi (Hemispherical head). Basically it was based on a theory that you could get more combustion or volume by angling the intake and exhaust valves then if you had them parallel. From Hemmings  Motor News book of Chrysler Performance Cars…”The ploy’s exhaust valve is located parallel to, but offset from, the cylinder axis.”

This increased the efficiency.  The hemi was constructed and designed to increase the efficiency with a more angled system. The shape that the valves make are semi-circular with the Poly being a little flatter than the Hemi.  I did the below image in Paint.

Poly-Hemi

 

This image is from Hot Rod and Hemis.com and shows the Hemi, Poly and the regular A series engine chambers.

www.hotrodandhemis.com Compare Hemi, Poly, Series A

 

Plymouth was not the top of the brand at Chrysler so back in 1956 it didn’t get a Hemi.  It did get was called the A series engine which came in 4 different displacement (277, 301, 303 and the 318).

To be continued.

Thanks for reading.

Tim

plymouth fury