Mopar 318/275 HP vs. Chevy 327/275 HP 'L-30'

[YY1]

The whole 327 is "better" than a 350 thing is the same issue folks have with the 340 being "better" than a 360.

I'm surprised one of the "no replacement for displacement" guys hasn't piped up.

Bottom line is that Chrysler engines were competitive with other makes despite generally having a slightly smaller displacement, and quite capable of outperforming them despite that lack of displacement.

 

[69 Cuda 440]

In 1966 Mopar did build-test a 300 Cubic Inch LA Engine
for Modified Speed Boat Drag Racing.

It was a 'sleeved' 273 with a 3.80" Bore, with specially modified
Cylinder Heads, with bigger Valves.

Unfortunately there was very little released information.

 

[69 Cuda 440]

I knew I'd find some information,,,

The 1966 'Proto-Type' 318 'LA Engine' was rated at 250 HP.

Compression-Ratio was 10.5-1

The Cylinder Heads had a larger 61.0 CC Open-Chamber Combustion Chamber.
Different than the #2658920 273 Cylinder Heads with the 57.3 CC Crescent-shaped Combustion Chamber.

The 'Proto-Type' Cylinder Head had 1.94" Intake Valves and 1.60" Exhaust Valves.

With special 'Exhaust Manifolds', and Dual Exhaust

Still searching for Camshaft, Intake and Carburetor Specifications.

 

[cudavert]

BTW, I always found it astounding that Chrysler never bothered in the slightest, to hop up the earlier LA 318's......I mean, geez, not even a 4-barrel?!

A 4-barrel, hi-po 318 was offered in cop cars such as the Diplomat in the '80s, but I'm not sure if it was available to the public or not.

True....I've seen quite a few of those in Diplomats in the boneyards. That's what I meant though, by "earlier"......meaning back in '67 through '72 or so. The 318's were rated at 230 with a 2-barrel and 9:1 compression. They would've been a cool setup with a 4-barrel, dual exhaust and maybe a little hotter cam. Chrysler had to have tested something like this at one time or another. Would've been another cool option for a Duster Twister or a Dart GT.

 

[ramenth]

True....I've seen quite a few of those in Diplomats in the boneyards. That's what I meant though, by "earlier"......meaning back in '67 through '72 or so. The 318's were rated at 230 with a 2-barrel and 9:1 compression. They would've been a cool setup with a 4-barrel, dual exhaust and maybe a little hotter cam. Chrysler had to have tested something like this at one time or another. Would've been another cool option for a Duster Twister or a Dart GT.

Chrysler did make a 4bbl 318. For marine use. My brother-in-law has an all factory 318 4bbl in his 1970 Penn Yan cabin cruiser. I've yet to determine what the heads and the intake are.

With that engine in the boat, makes me wonder why they didn't make one for passenger car use.

 

[Louie70Dart]

The 327/375 HP was a mechanical fuel injection motor. I saw, years ago, where someone planted that engine in the back of a Corvair where the rear seat would be. Monster mid-engine hot rod.

 

[69 Cuda 440]

Got some of the information from 1966 Production Planning {Marine Division}

To combat the 1965 Chevrolet 327/250 HP {Code L-30}.

Chrysler {Marine Division} had a proto-type for the LA Engine using
the 318 size off of the Poly Engine.

The original '318 LA-Marine' was to be rated at 250 Horsepower, utilizing
10.5 - 1 Pistons.

The Camshaft {Solid Lifter = .425" Lift / 248* Duration / 26* Overlap}
and Valve Train Components {Valve Springs = #210 lbs. Valve-Open}
from the 273/235 HP Commando were also utilized for the 1966 318/250 HP 'LA Marine'.

The Cylinder Heads had 10% larger runner-ports, a larger Combustion Chamber
{Open-Shaped with 61.0 CC's} and larger Valves.

Chrysler also took Valves from the early 392 Hemi engines {2.00" Intake and 1.75" Exhaust}
and cut them down to size {1.94" Intake and 1.60" Exhaust} to fit the new LA Engine
Cylinder Heads.

The Cast-Iron X-Shaped Low-Plane Intake from the 273 Commando was also
utilized, but the throttle bore openings were increased in size to 1 11/16".

The Carburetor was a reproduction of the Carter AFB #3447 600 CFM unit
{1 7/16" Primary x 1 11/16" Secondary} which was from the earlier
426 Max-Wedge Cross-Ram engine.

 

[69 Cuda 440]

Yes,, there was a significant difference between the 1966 Chevrolet 327 Engines.

* L-30 {327/275 HP}
* L-75 {327/300 HP}
* L-79 {327/350 HP}

The famous 327/350 HP 'L-79' #3890490 Aluminum Dual-Plane High-Rise Intake.

With the 'special' Holley #3245 - Model 4160 Series {585 CFM Carburetor}, this made that
327 Mouse-Motor roar.

 

[69 Cuda 440]

1966 318 LA-Engine 'Marine' Proto-Type

318/250 HP '1966 LA-Engine'
* 10.5-1 Compression-Ratio
* Camshaft .425 Lift / 248* Duration / 26* Overlap
* Solid Lifter
* Valve Springs {273 Commando}
* 318 LA-Engine Performance Cylinder Heads
* 1.94" Intake / 1.60" Exhaust
* Cast Iron Low-Plane X-Shape Intake {273 Commando}
* Carter #3447 AFB {600 CFM}
* Dual-Point Distributor
* Exhaust Manifolds {273 Commando}

Familo Dodge and 'Performance Associates' out of Pomona, Califorinia put a
318 LA-Engine in a 1966 Ddge Dart GT 4-Speed in early-1966, but swapped
out the Camshaft and Intake Manifold.

They test ran it in AHRA Class 'Formula 5 Stock' 'F/Stock' at Fremont Dragstrip in 1966.

'Performance Associates' claimed the 'tweaked' 318 LA-Engine put out
265 Horsepower, less Headers.

And could run with the 1966 Chevy II Nova SS 327/275 HP cars.

 

[69 Cuda 440]

Ed, this is not the car that had the 1966 Proto-Type 318 LA-Engine but it
was the same Performance Team.

Ron said the prepped 318 had the following;
* 10.5 - 1 Pistons
* 318-X Cylinder Heads from Kenyon
* Solid Camshaft .450"/.455" Lift ~ 260* Duration ~ 55* Overlap
* 250 lb. High-Load Rate Valve Springs
* Tubular Pushrods
* Offenhauser Dual-Plane Square Bore High-Rise Intake
* Holley Carburetor #4160 Series {585 CFM}

Rough Calculated to put out close to 270 Horsepower