The LA Motor "Block"

Sorry guys i seemed to have started something and left everyone hanging.
I was asked by David a question about a street ride so I thought I would share it.

Hi David, I am sorry I have not been around, but I am moving a house for my son and I have been like a one-legged man in Butt kicking contest. If you are going to build a Mag. Motor or a roller LA motor really it come down to machining and cleanliness. You can unleash a lot of power if you know how. Ok a simple build to me starts with the block. Clean all the slag out of the return oil ports, then It needs to be cleaned, squared and I like to line hone it. Now sit down and be honest with yourself, “this really the hardest part, no really” what are your expectation, Power, ¼ mile times, 1/8 mile times, Torque and so on. Are you going to use nitrous, weight of car or truck, gear, and trans. Then know the strengths and the weakness of your engines, they all have them. So the 1990 block was a roller engine, not a magnum, I would spend my money like this, prep the block. Take it in have it cleaned, new cam bearings, bore it .030 or so. I say it like that because if you get on Facebook marketplace you will find new pistons that some bought and didn’t use for a very reasonable price. Use a HV oil pump and low pro 7qt oil pan. Upgrade your rod bolts, and grind the casting seem of the rods and free float the pistons. The difference in weight between the stock piston and a hypereutectic piston is between 6 to 8 lbs off the rotating assembly. LA heads are very efficient and can be used up to 10 to 1 with out any trouble. I like the -302 heart shape heads for a good solid street build. Don’t guess call the cam manufacturer and be honest with them on you build and ask them what cam they would recommend. Or buy a matched set, I like the Edelbrock RPM intake and cam with a 1500 to 6500 RPM range with good vacuum, nice set up. If you want torque use a Edelbrock 600 cfm carb. Or if you are street racing a little, use the 750 cfm carb. Then install a 2000 to 2500 stall convertor with a 3.91 to 4.10 gear and have fun. The machining, heads, I talked about, and the RPM cam, intake, carb, with a 3.91 gears in a A-Body will make 400 to 425 hp and run low to mid 11’s at 125 mph in the ¼ and mid to high 7’s in the 1/8, go have some fun. PS if you use Nitrous don’t go over 150 hp with fel-pro head gaskets, and don't go over 250 hp with Cometic head gasket.



Oiling System "I have used this system for years"

Herb McCandless


Since this info is over 10 years old, some part numbers and other details may not still be correct.

"LA ENGINE OILING”

In an A engine with a solid or roller lifter cam we highly recommend installing the Chrysler P4120603 lifter oil block off tube kit. Regardless of whether you use a hydraulic, solid or roller cam we recommend the following modifications.

Purchase an 8-10” long 9/32 drill bit. Remove the main caps and on mains number 1-2-3-4 there is an oil passage which goes from the top of the main saddle to the lifter galley on the passenger side of the block. Slowly drill these four passages to 9/32. Cast iron is very hard to drill without the bit trying to hang so do not try to rush this job. If you happen to break the bit you will have real problems.

Take your oil pump and drill the neck of the pump, the section between the rotor and the main cap, 1/2 inch. Take a sandpaper roll (the kind used in porting and polishing heads) and go in the pump above the rotors and deburr and slick the area above the rotors. You will need to slick the hole in the pump neck that you have drilled. Drill to 1/2” the rear main cap where the oil goes through and polish with the sandpaper roll.

You will need a 10” long 1/2” drill bit for the next step. With the rear main cap removed, look in the hole where the oil goes into the block. There is a 9/16 freeze plug which diverts the oil through the oil filter. Remove this plug by inserting a 1/4” rod through the hole where the oil pressure gauge goes in the top side of the block. Drill the hole 1/2” up to the lifter galley where the plug was removed. Remove the oil filter and any adapter or plates from the block. Remove the pipe plug from the block that is under the filter. Drill to 1/2” both holes that go from the filter to the passage that feeds the lifter galley. Now remove the pipe plug in the rear of the block, behind the oil filter and drill this passage to the center of the oil filter bolt 1/2”. DO NOT DRILL THE PASSAGES FROM THE MAINS TO THE CAMSHAFT. DO NOT RESTRICT THE OIL TO THE ROCKER ARMS.

Once all passages are drilled, completely clean the block very thoroughly. We use a Milodon #34010 Brush Kit to clean all the oil passages, and it works very well. Once the block is completely clean, replace the 9/16 plug that diverts the oil to the filter and the plug under the oil filter. If you make the above modifications you have greatly increased the volume of oil that feeds the crankshaft and the bearings of your A engine.

We highly recommend the Milodon 10 quart oil pan with the swivel pickup. This system comes with a pump cover and a 1-1/4” rotor. Using the 1-1/4” rotor greatly increases the oil volume that goes into the motor. The swivel pickup makes sure there is always oil at the pickup. We also recommend that you use a fully grooved (wide grooved) main bearing set.

We DO NOT recommend using a stock type oil pan that has been cut and deepened as these pans can run out of oil under acceleration or deceleration. The reason for this is that these pans are not baffled properly. While the cost of a good oil system is expensive, it is not near the price of a new engine