OK,the Canadians made the 313 Ploy head motor and it was sold in the commonwealth countries ( Australia,England etc ) and not fitted to US market cars,where the 318 was used from 1957 to 1965-7. Are there ANY experts on polys who can describe the actual difference between two engines besides the different bore diameter?
Are you referring to having read this article? http://www.allpar.com/mopar/a-engines.html Don is also a great resource on these: http://www.jalopyjournal.com/forum/member.php?u=20716 ~Jason
Re: http://www.allpar.com/mopar/a-engines.html The single shaft (Hemi-based) Poly can be identified by its separate valley cover ...except that all poly motors are single shaft. The differences: all hemi engine intake and exhaust rockers pivot in opposite directions on 2 shafts all poly intake and exhaust rockers pivot in opposite directions on 1 shaft all LA and other wedge intake and exhaust rockers pivot in the same direction on 1 shaft. overhead valve design with dome-shaped heads It could be called many things, but this isn't one of them. older poly engines essentially, Hemi engines with modified combustion chambers and single rocker arms Not too accurate, the entire head casting and all valve gear is completely different except for head bolts and water, and again confuses single rocker arm with single rocker shaft. 16 rocker arms for both, of course. in the ease of manufacturing. While Dodge, DeSoto, and Chrysler had relatively small sales numbers and could live with the low pace of building the poly V8s, Plymouths high production required something cheaper and faster to build The A head isn't any cheaper to build than any other poly head (with the exception of cast-in rocker stands), but it's cheaper if there is only 1 line instead of 3 and you're not using hemi blocks.
Im not a expert by any means.. But I did learn from a source here that the Canadian 313 and 303 has a different piston Diameter than the American 318.. I might be wrong... The Flat Canadian six from 55,56 is also different than the U.S made 6 cyl. engine..
hey Plodge,thanks for the reply,. Yes,the bore dia is smaller on the 313 but I always understood them to be a different engine and I couldn't get heads from a 313 to fit a 318 Chrysler where as guys have said they are the same engine. I call the 303 and 313 the Commonwealth Engine because it was only sold in British Commonwealth countries. There are few 313's laying about here in OZ and if they are the same engine it would be an even cheaper way to get into a poly for a cheapjack rod... Cheers!
I thought I read the question right.. I didnt realize that you were talking about the small 318.. or what would of been a 273 prior to that.. in comparison to a 313 big block ..or a 318 Big block. The term poly.. is confusing.. even the 318 is.. It seems Mopar was all over the map..
are you sure? I have friend in Calgary here with a 313 in a 56 Dodge Custom Royal.. He just sold a 66 charger with the large 318.. Did we in canada only have these engines? Small block 318 I know are much different.. the 55 to your left has a 56 Fury 303.. which also was a canadian engine.. used for trucks..
Thats right,I wasn't talking about the 'other' engines Just the poly's. The 303-313 commonwealth engine was only sold in Canada (where it was made) ,Australia and England where Bristol used it in their cars. Desoto Trucks had them in Australia (yes,Desoto trucks) and dodge pickups. At the same time US made Combine harvesters were arriving in Australia with Chrysler 318 Polys which confuses the hell out of a lot of people who confuse the two. Canada was still fitting the chrysler 318 polys in 1967,two years after the US stopped selling them. Besides the non fitting valve covers are the blocks in anyway similar? Abomination, I always thought they were different but I have several 'experts ' here tell me the engines are the same ..I disagree but don't have any here at the moment to check for myself.
The valve covers are the same. The engine in my T-bucket started out as a 313 Dodge truck engine of 1960 vintage. I had it bored and fitted standard sized Dodge pistons from a 318 and changed the timing cover, water pump and crank pulley to 318 items. The Edelbrock valve covers which I bought in 1963 fitted onto that block with no probs, 3 bolts needed tho! As far as I can make out there is no difference between the 313 and the 318 blocks but I am not going to pull the 313-now 318 apart to compare parts with the other 318's which I have. swifty
I worry that folks are still confused about the original question. The use of the term 'Chrysler 318' does not help, and most people in the states have no clue what was happening over there... If there is confusion go back and re-read the article in the link: http://www.allpar.com/mopar/a-engines.html There are some parts common to the A and the LA, but they are different engines. And for those that insist on calling the A engine 'wide' block or 'big' block, if you sit a bare A block next to a bare LA you will find very few differences. The difference is 99% in the head design. Please call them what they are. .
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