318 Poly to ???

[thembsnyder]

Guys and Gals,

I have a 318 Poly that I was going to do some upgrades to but being behind the power curve I have now found after some research that finding upgrades for the Poly 318 is quite difficult and very expensive. I was wanting to put on a 4 barrel intake, new valve covers, maybe a rebuild kit....yeah..not so much anymore.

Here is my question. What engine would work the best with the current engine mounts. I am unsure of what transmission I have at this point and I am not at home so I cannot look at it either, it is a 4 speed manual transmission is all I know at this point.

I was figuring the 318 V8 after looking at some of the posts, but I was hoping to maybe bump up to a 383 or maybe go nuts and get a 440.

[EarlKann]

Any LA smallblock 273/318/340/360 will interchange fairly easlily with only a few minor details to watch for (internal vs external balance).

If you want to go to a big block 361/383/400/413/426/440 you're going to need a new transmission (auto) or new bell housing (stick).

[thembsnyder]

Earl, thanks that is what I needed to know. I have found a 318 V8 out of a 89 Dodge 2500 van. Not a bad price on it either. Just might have to get me one soon I guess.

thanks again

[Duh]

Sir

All LA-318's are a 50 plus pounds lighter than any A-318 so you have a Power to Weight Gain enhancement just by bolting
it to your truck.

The 1989 LA-318 has a Looong Nose Water Pump Unit on the front so you will need to get a new Water Pump to Timing
Chain Housing Gasket and use the short Unit of the A-318. It also has The Pick up on The Right and you need for it to be
On The Left

Or just find a way to re-locate the Radiator some forward

Look around for any Pre-1975 set of Valve Tappet Cover's from any LA Engine so you have the correct appearance.

This also applies to a set of pre-1975 Center Dumping Exhaust Manifolds vs the after 1975 Exhaust Manifolds

The A-318 Carburetor is a "Push Design" and The 1989 Unit is a "Pull Design". With a new Carburetor to Intake Manifold
Gasket the A-318 Carburetor will bolt to the 1989 Intake Manifold. Or with some minor engineering the 1989 Linkage
can be made to operate in the 1966 Truck

Or

1. You can obtain the same power enhancing by using The Silicone Fan Drive from The After 1980 Engine with The 1980
plus Engine Cooling Fan - bolted to the Poly's Water Pump. The Silicone Fan Drive Unit also betters your MPH Data.



Rodger & Gabby
FltSgt@outlook.com
COS

[Stevenow]

Since there is so much smog-related stuff on the '89, won't he have to ditch the intake? Aren't the newer engines built with compression ratios that make them just anemic for horsepower and not able to withstand upgrades? Tell me if I'm wrong- working off a bad memory at best!

Also, the LA engine- is it the same as the Police Interceptor motor? I had two friends in the early 80's who had those and those motors COOKED! Better on gas, too- right?

Craigslist seems to have an abundance of guys who built up a motor and then had a family emergency/life crisis/whatever (been there, done that) and are ditching the rebuild for pennies on the dollar of what they spend. You might get a nice 360 there!

Good luck,

Stevo

[thembsnyder]

Guys,

Thanks for all the excellent information, this is all news to me.

My plan was to go with another intake manifold, new 4bbl carb and valve covers. With this I would also probably replace the water and fuel pump.

With all the different designs of the carbs, (push/pull, vacuum and all that) what would be a correct model of 4 Barrel Carb for me to acquire that would match my current linkage in the 64, it has a manual choke in it right now with a really tiny 2 barrel carb.

thanks

[40YearOldFury]

Guys,

Thanks for all the excellent information, this is all news to me.

My plan was to go with another intake manifold, new 4bbl carb and valve covers. With this I would also probably replace the water and fuel pump.

With all the different designs of the carbs, (push/pull, vacuum and all that) what would be a correct model of 4 Barrel Carb for me to acquire that would match my current linkage in the 64, it has a manual choke in it right now with a really tiny 2 barrel carb.

thanks

I'm pretty sure a 4bbl was not an option in 64 on any truck. Maybe a HPP truck. For a while I ran a Edelbrock 1406 or maybe a 1404 on my 318 Poly and it worked very well. I did not have to change the linkage.

[Duh]

Sir

For any year "Poly" ever used in any truck - there was never a 4 bbl option ( as just said this morning ).

The last production year for a 4 bbl Poly option was 1962 in Plymouth and Dodge car's. Find a 4 bbl
Manifold and they are $300 plus price tag for a used one.

For The LA Series of 318's, MoPar never made one to sell to the public that had a LA-318 part number. If
you do find a LA-318 with a 4 bbl Intake Manifold it is a LA-273 unit if it is the most correct fit. All of
these are a "sq bore" design.

The LA-340 ( "sq Bore" ) or LA-360 ( "Spread Bore" ) units will bolt on - but the Manifold to Head Port
fitting size is equal to a 3/4 inch pipe to a 1/2 inch hole.

The most correct 4 bbl CFM size for all Hwy/ Street used 318 is 390'ish CFM's ( even though people do
bolt a larger sized CFM Carburetor on top because the thought is bigger is better ).

****
The 1989 LA-318 has The Pre-Magnum Designed Heads. This means they produce a better Power and
MPG Enhancement than any 1967 to 1986 set of LA-318 Heads.

Note: These are not 360 heads bolted to a 318 ! Nor are they a 360 Spread-bore Intake bolted to the
same heads used with some "police packaged 318's", that are found in some 1980 - 1985 something
Plymouth or Dodge Car's.



Rodger & Gabby
FltSgt@outlook.com
Colo Spgs

[thembsnyder]

Guys,

Thanks again for all the information.

One more...does it matter what year of engine I get, as long as it is not EFI or anything of that nature. I am planning on putting on a new manifold and carb anyway to dress it up and new valve covers. So does it matter if I get a 70's or 80's model 318?

[EarlKann]

Guys,

Thanks again for all the information.

One more...does it matter what year of engine I get, as long as it is not EFI or anything of that nature. I am planning on putting on a new manifold and carb anyway to dress it up and new valve covers. So does it matter if I get a 70's or 80's model 318?

If you're getting pre EFI there shouldn't be any differences in mounting or anything like that. There are some notable differences between smog and pre-smog engines though. I'd prefer a 70's engine over somthing mid 80's with lower compression and those crazy AIR/smog manifolds & ports on the exhaust side of the heads. (don't know it that's just a CA thing or not).