Milling 360 heads for a 318

[evans68cuda]

Hey all! I found a set of 76 360 heads. Casting is 3769974 for 250 obo. Cylinder 2 on my 318 has no compression so I'm hoping it's a stuck valve. I'm thinking that while I'm there I should get new heads so I'm thinking of these 360 heads. What would I need to do to make them fit? New pushrods? And what cc would I want the combustion chamber to be for 10:1?

 

[racerdan80]

Different pistons with higher compression height. Measure the volume of the 360 heads if you acquire them, don't take it for granted that they will be as advertised in books.

 

[318willrun]

You need nothing. Rocker arms and push rods work. I've cut 360 heads .040 more than once for 318's and NEVER had to cut an intake. If you want to go more in depth with a total rebuild or whatever, but the answer to your question is nothing. cutting the heads alone will not get ya even close 10.1 on a stock short block 318.

Just make sure the 360 heads are in good shape. You know, valve guides, valves seals, and give them a leak test to be sure the valves are seated.

 

[racerdan80]

For what it's worth, my 80's 360 heads are listed as 66-72cc. They measure out at 78. There are online compression calculators that can help you with dimensions needed to make 10:1 static compression ratio. However, depending on your combination of parts as a whole, you might not be able to run on premium pump gas. Calculating dynamic compression comes into play then. Will this be a drag only motor? Street/strip with occasional highway use? What is the gearing and type of transmission? That will all be a big factor in selecting a cam.

 

[evans68cuda]

What cc would I be looking at if they were milled like say .040? And it's going to be just a fun driver. Not looking to really race it. The plan originally was to get a 408 but that's probably going to be next winter. I really just wanna drive it so I'm throwing the 318 back in but want more power. I already have a performer 318/360 Intake, headers and I think a bigger cam was put in at some point. I may put a cam in to not sure yet. It's got a 4 speed and unknown gears. I plan on swapping like 3.50 in so I can take it on the highway occasionally.

 

[d1970]

just did this. 318 .30 over 323 CI. Mopar cam 410/425 248-256, 1000-5000 rpm, 360 (3769974) heads .50 off (50 is the most you can take off safely) and used a thin head gasket, 9 to 1. Original rockers, push rods and did not need to mill the intake. A very easy revving engine and teeners like to rev. I installed a FBO limiter plate in the distributor, locked 14 degrees, 20 initial and 16 in the can, total 50. I used some of FBO springs to adjust the curve so it was all in a 2600 rpm. Installing 3.55 sure grip in place of 3.08 gears which should help with the getup and go.

 

[66fs]

What cc would I be looking at if they were milled like say .040? And it's going to be just a fun driver. Not looking to really race it.

.040 should give you about 65cc chambers. I always mill the intake side .038 also. That's the spec. Use a 340/360 intake if you step up to the bigger ports, even a stock cast iron 340/360 intake.

 

[SWED67barracuda]

If you mill your heads dont forget to put shims under the rockershafts for correct geometry.

 

[JBurch]

What cc would I be looking at if they were milled like say .040? And it's going to be just a fun driver. Not looking to really race it. The plan originally was to get a 408 but that's probably going to be next winter. I really just wanna drive it so I'm throwing the 318 back in but want more power. I already have a performer 318/360 Intake, headers and I think a bigger cam was put in at some point. I may put a cam in to not sure yet. It's got a 4 speed and unknown gears. I plan on swapping like 3.50 in so I can take it on the highway occasionally.

You have to know where you are starting to know where you are gonna end up. At the moment you are just doing a pure guessing game. Measure a head, KNOW what the volume is. Cut .0048 of an inch to reduce the chamber 1 cc. Mopar engine book and Larry Shepard of "How to Hot Rod Small Block Mopar Engines" state that for every .010 cut from chamber face, cut .0095 from the intake face.

From what 318willrun says, he's had good luck not cutting intake face, no reason to doubt him, so maybe you won't/don't have to do that. Time will tell.

Good luck, have fun.

 

[318willrun]

You have to know where you are starting to know where you are gonna end up. At the moment you are just doing a pure guessing game. Measure a head, KNOW what the volume is. Cut .0048 of an inch to reduce the chamber 1 cc. Mopar engine book and Larry Shepard of "How to Hot Rod Small Block Mopar Engines" state that for every .010 cut from chamber face, cut .0095 from the intake face.

From what 318willrun says, he's had good luck not cutting intake face, no reason to doubt him, so maybe you won't/don't have to do that. Time will tell.

Good luck, have fun.

True, and also you have to make sure the heads haven't already been cut before cutting them again.