318 La with 360 heads

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Mopar Vinnie

Mopar Vinnie

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What are the advantages and disadvantages of running 360 La heads on a 318La. 974- heads 1974-75
 
If your putting unmodified 340/360 heads on a stock 70's-up 318 you loose static compression on an engine that doesn't have that high of compression to begin with and things get worse if you start to put a larger cam in to take advantage of the larger ports.

Now its not a bad thing if you plan to rebuild the 318 and put pistons in that work for your power goals. At that point, you might look to Magnum heads or an aftermarket head with closed chambers to gain quench. But its all about what your intended goal is.
 
@dano. Absolutely correct! If you have dished (low compression) pistons it will probably be a dog. The one I did this with had lots of torque but would not rev. Put 318 heads back on and it ran great!
 
Mopar Vinnie said:
Street/strip 350hp+
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That's a tall order for a 318, but can be accomplished with a well thought out plan. I would recommend either a pretty stout solid flat tappet camshaft or a solid roller with some GOOD flowing heads.
 
RustyRatRod said:
That's a tall order for a 318, but can be accomplished with a well thought out plan. I would recommend either a pretty stout solid flat tappet camshaft or a solid roller with some GOOD flowing heads.
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Would the 360 heads would work
 
Mopar Vinnie said:
Would the 360 heads would work
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Yes, given you have pistons to generate enough static compression. Just slappin 360 heads on an otherwise stock 318 gets compression down into the 7s. That's not very conducive for making power with small cubic inches. With the correct pistons though, it would work well.
 
Mopar Vinnie said:
Would the 360 heads would work
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With some port work, possible milling, and a good valve job. What I have found is most heads are beat to death and the 1.60 exhaust valve seat is difficult to repair if sunk in. To correct, port, and get them to work well you'll be into the cost of aftermarket heads. This is given you have a shop do all the head work.
 
It’s not hard at all to make 350hp with a 318 using 360 heads.
The real question is...... will what it took to make 350hp with the 318 be a combo that works well with the plans you have for the car?

It’s really going to be a different type of combo than say..... a 350hp combo built from a 360.

It won’t have the low end grunt you’d get from the 360 based combo, so you need more gear and stall to go along with the bigger cam you used to get some top end out of the 318..... which is how you got it to 350hp.

A true 9.5+CR, Mildly reworked 360 heads(215-220-ish @.500), fairly hot cam, nice intake/carb/headers.
Then pair it up with a 3500+ converter and 3.55-4.10 gears and you’re good to go.

The equally built 360 will be about 400tq/400hp.
 
Stock pistons with 340/360 heads will be 7.5 compression, however the increase in flow will offset the loss in compression...
 
 
PRH said:
It’s not hard at all to make 350hp with a 318 using 360 heads.
The real question is...... will what it took to make 350hp with the 318 be a combo that works well with the plans you have for the car?

It’s really going to be a different type of combo than say..... a 350hp combo built from a 360.

It won’t have the low end grunt you’d get from the 360 based combo, so you need more gear and stall to go along with the bigger cam you used to get some top end out of the 318..... which is how you got it to 350hp.

A true 9.5+CR, Mildly reworked 360 heads(215-220-ish @.500), fairly hot cam, nice intake/carb/headers.
Then pair it up with a 3500+ converter and 3.55-4.10 gears and you’re good to go.

The equally built 360 will be about 400tq/400hp.
Click to expand...

I agree with everything except that an equally built 360 would make a different hp eg. 400hp.
Here one example of 3 similar engine builds with different displacement, the rpm where the powerband is the main difference.

 
Mopar Vinnie said:
What are the advantages and disadvantages of running 360 La heads on a 318La. 974- heads 1974-75
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Good set of heads. Don't do any unshrouding, the 318 is smaller and going bigger than it is will create a ledge. Check the chamber size. You may need to mill them about .040, the last set I measured were 72cc. The low lift flow has to be a lot bigger to see the offset mentioned.
 
MOPAROFFICIAL said:
Good set of heads. Don't do any unshrouding, the 318 is smaller and going bigger than it is will create a ledge. Check the chamber size. You may need to mill them about .040, the last set I measured were 72cc. The low lift flow has to be a lot bigger to see the offset mentioned.
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How do y do that
 
Mopar Vinnie said:
How do y do that
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Get on jegs or Summit and get a CC kit and read the directions.
Or...
If you have something that measures Cc's or ounces and you can convert to cc's... use a cd case, drill a hole, grease the head deck to seal the case cover, with valves and spark plug installed..then pour starting with x amount in measuring cup/tube/wtevr and measure what's left after chamber fill with all air holes out...convert and that's your chamber size.
 
The kb 167 , then ya probably dont need but a .010 clean up to dial it to 9.5-9.8 comp.
I though it was one of those... 'drop big heads on a stock bottom with pistons as deep as gophers' kinda deals.
 
If I was doin' a 318, which I never will;
I'd go small closed chamber aluminum Magnum heads and pistons .009 above the deck for a Q of .030 with the FellPro .039 indestructible head gaskets.
Then I would figure my Scr.
Then I would select the biggest solid lifter cam that will still make 180/185 psi.
I wouldn't care how much power or how little power it made. That pressure is gonna a make a two-gear rocket, and fantastic fuel mileage, so I can drive it everywhere all the time.
She won't need much if any stall, and will like 3.23s.
Most of the money you spend on the alloy heads will be saved in re-using the TC and gears. The rest will be saved in the reduced annual fuel consumption, by not having to run a 2800 and 3.91s.
I mean you could still run something like that,....... but you don't have to.

In my crystal ball I see 10.7 Scr and an Ica of 57* @800 ft.

If I was doing it.
 
PRH said:
It’s not hard at all to make 350hp with a 318 using 360 heads.
The real question is...... will what it took to make 350hp with the 318 be a combo that works well with the plans you have for the car?

It’s really going to be a different type of combo than say..... a 350hp combo built from a 360.

It won’t have the low end grunt you’d get from the 360 based combo, so you need more gear and stall to go along with the bigger cam you used to get some top end out of the 318..... which is how you got it to 350hp.

A true 9.5+CR, Mildly reworked 360 heads(215-220-ish @.500), fairly hot cam, nice intake/carb/headers.
Then pair it up with a 3500+ converter and 3.55-4.10 gears and you’re good to go.

The equally built 360 will be about 400tq/400hp.
Click to expand...

Maybe not for you, not for me, not for a lot of people, but for someone asking if 360 heads will work on a 318 it might not be as easy. Think through someone's perspective other than your own sometimes.
 
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