360 small block & head indentification?

Jfalquez,

   

   I don't know if this is any help to you but the casting number 4071051 was used on;

1977-1980 360's and

1981-1982 318 HP (police cars, I suspect)

The 360 heads with that casting number had 68.4cc chambers and

the 318 HP's had 65.5cc chambers.

   Trouble is my books only go up to 1982 (I guess I'm old school) so they could possibly have used that same casting in 1986 or maybe the engine was rebuilt at one time and they used older heads. They're still good heads but one will be a little lower compression than the other. I would check the chamber volume to be sure. Good luck!!

...........Robert  

Thanks, Hmmmmm.....I wonder if the "HP" on my casting hints that this could be the 318HP heads?  I'll ask the head shop guy today.

Robert, my wife said "IF we're going to vegas, we're taking HER car, not my old truck"....kinda defeats the purpose :-) or course I really didnt tell her that I would be going to "just work on the truck" Ha Ha.... I'll probably try the column swap this weekend

whats the rest of the casting number on the head. The H.P. may me the heads came off an 81-83 318HP.

Just a thought.

Here's the numbers/letters and their location:

HEAD #1

on the front end face where accessories bolt up are the numbers 316, they look like they were put there with a standard hand number stamp.

On the valve (headgasket) side is the casting number 4071051 and what sort of looks like a distorted "A" at the end of the number.  However it may just be nothing at all, it's hard to tell. Other than the possile "A", the rest of the casting number is crystal clear.

On the rocker arm side on the first intake runner is "21G" and on the other side "P3". These markings were cast in the head

On the rocker arm side on the 2nd intake runner is the number "6" on one side and the letters "HP" on the other. These markings were also made in the casting process and are crystal clear.

HEAD #2:

on the front end where accessories bolt up are the numbers 664, they look like they were put there with a standard hand number stamp.

On the valve (headgasket) side is the casting number 4071051 and what sort of looks like a distorted "A" at the end of the number.  However it may just be nothing at all, it's hard to tell.

On the rocker arm side on the first intake runner is "17G" and on the other side "P3". These markings were cast in the head

On the 2nd intake runner is the number "6" on one side but I cant tell if the the letters "HP" on this head as there is much baked on oil. These markings were also made in the casting process.

Those are the only markings on these heads.

Jesse

Solution- tow her car with your truck. That way you will be taking her car. Hehe

.............Robert  

Jesse,

Yea, it sounds like they are the 318 HP heads. If they are, that's good. They have the smaller chamber. It's easy to figure out the chamber volume, just get a syringe that is marked with cc's (an old printer ink refill syringe will do) and a piece of clear plastic with two small holes in it. A piece of plexiglass or lexan will do, just make sure it's big enough to cover the chamber. Smear a little gasket sealer around the outside of the chamber and stick the plastic to it then fill with water with syringe (valve side of head up, obviously) keeping track of the amount of water and WAHLAH, your chamber volume in CC's.(don't forget to put the spark plug back in so you don't end up with 7,000,000 cc chambers, Hehe)

..............Robert  

If you look at it this way. 4071051 is a casting number for a 1977 to 1979 360...but, it's also a number for a 1981-1983 318 H.P.

I'd say the H.p> in the cast gives it away. These are 1981-1983 318 H.P. heads.

Service number is 4100408-9

Jeremy

Sounds good to me.

..........Robert  

Well, I finally got the heads back from the machine shop. Had them worked over with all new components including seats and milled .005 to clean them up. It looks like these heads are the High Performance model of the 4071051 castings.  The volume of the chambers turned out to hold an average of 64cc of liquid (so they must be the 65.5cc model). Do you think that this is a good thing (pro's and cons)? Now to get the block back, I can start the build up :-)  

These heads will be great on your 318! Use the J heads on your 360. I checked and found thay if you use the big valve heads on the 318 that you need to open the top of the cylinders to unshraud the valves or you won't get any gain from the bigger valves.  

yeah, I was reading the same thing in one of past few months mopar magazine letter section.  What is involved in unshrouding the cylinders? Can I do this without pulling the pistions (rotate crank to lower pistion and hit it with a dremel)?  OR is this something that the block would need to be disassembled and taken to a machine shop? Is there a method that works better than others? I wonder just how much area of the cylinder wall needs to get expanded out to 4.00?

When you say to use the J heads on the 360....do you mean these 4071051 HP 64cc (65.5) heads (these are the ones from the 86 D-250 van, 360 I pulled)? Or am I stuck just being able to use them on the 318 and find something else for the 360?  The bottom half of this 360 motor is at the machine shop being bored and prepped for the rebuild.  I'm thinking that the ports, valves, intake port volume, etc might all be equal when compared to a normal 360 J head and the only difference is the smaller combustion chamber volume . Am I wrong?  Thanks again.

Jesse

If the HP heads have 1.88" intake valves they will be good heads for the 360 if not keep them for the 318, you said you got an extra set of heads are they J heads? The small chambers on the HP heads might be a problem with the 360, you need to make sure the pistons don't come to the top or over the top of the block deck if using the HP heads. You will need to take the 318 block to the shop to have it opened up to 4.00" to unshroud the valves if using heads with 1.88" valves or larger.