1972 318 la

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HEMI_POWER

HEMI_POWER

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So the Dart I am looking at has a 318 in it with the stock automatic. What would I need to do to build this engine up? What should I look for as far as heads go? I would like to get to the mid 300's (325-375) if it's possible.
 
375 hp is doable but,, by the time you spend the money it takes to get there you may be asking yourself why you didnt start with something bigger.
 
375 is a big number for a 318 ... all depends on how much $$ you want to spend.

I've got a mild 360, and it put down 285 to the wheels.. I'm happy with that
 
I have access to a 1999 Magnum 360, but I really do not feel like messing with the computer and EFI.
 
Check your local kijiji. I bet there will be a handful of "la"360's for sale all for a few hundred bucks.
 
Well, I will answer your original question. I personally like the 308 heads off of 89-91 360's. You will gain a lot of flow, however, you will loose some compression. Have them cut about .040 and that will help. If you are willing to put different pistons in your 318, like KB pistons, then cutting the heads would not be necessary. I would suggest a 670 street avenger holley carb on a weiand action plus intake. A cam that is roughly the size of a stock 340 would work well, or maybe a little bigger (not much). So, the carb, intake, heads, cam and headers should get you a little more than 300 gross horsepower. If you bore it .030 over and use KB piston, you would be even closer to the 350 mark. But, this combo would need at least a 2400 stall converter, and at least 3.23 gears. More stall and gears would even make it quicker. Finally, yes, the 360 magnum would be a great choice....
 
318willrun said:
Well, I will answer your original question. I personally like the 308 heads off of 89-91 360's. You will gain a lot of flow, however, you will loose some compression. Have them cut about .040 and that will help. If you are willing to put different pistons in your 318, like KB pistons, then cutting the heads would not be necessary. I would suggest a 670 street avenger holley carb on a weiand action plus intake. A cam that is roughly the size of a stock 340 would work well, or maybe a little bigger (not much). So, the carb, intake, heads, cam and headers should get you a little more than 300 gross horsepower. If you bore it .030 over and use KB piston, you would be even closer to the 350 mark. But, this combo would need at least a 2400 stall converter, and at least 3.23 gears. More stall and gears would even make it quicker. Finally, yes, the 360 magnum would be a great choice....
Click to expand...

I was thinking this may be a good start

PISTONS: KB Flat Top (KB167)
CAM: Comp Cam XE275HL
HEADS: EngineQuest (CH318B)
PUSH RODS: Comp Magnum (7960)

Do you possibly know what auto transmission came stock in the '72 Dart Swinger? Would it be worth it to just swap in a A833 4 Speed?
 
Your tranny would almost certain be a 904. They were typically the slant 6 and 318 tranny in cars. They work well if built right. Your combo you selected would work great. I might go with a little less cam (comp 268 cam), unless you plan on running at least a 3000 stall and at least 3.55 gears. Also, the EQ heads are great, but not necessary for the horsepower you want. You could save some money by using 360 (pre 92) heads, with mild porting. It's all up to what you are willing to spend. Just remember, big flow (heads and cam) require lots of stall and gears which drastically take away highway cruising speed, gas mileage, and street manners in general. With out the high stall and gears, big cams and big flow heads kill low end torque creating a dead dog off the line.
 
Thanks for the INFO. I have been reading a lot about the "302" heads as well. Would that be a good option or should I just look for pre '91 360 Heads?
 
While I like the bigger is better idea, I also am with the build what ya got. Spending money on a 360 to start could have been a set of slugs and maybe a little more.

The Magnum engine will need a Magnum vertical bolt intake. They can not use an LA intake. They can not use LA heads due to the lack of oil holes through the block to feed the valve gear through the head. On a Magnum engine, oiling is done through the pushrods.

If you have a Magnum engine, just swap the cam, intake, distributor to an earlier on with vacuum advance and add a carb and headers. Stay with the roller cam and reuse the OE roller lifters and spider. (AKA, lifter hold down.)

IF you want to do the 318 for a inexpensive cost, add cam, intake, 4bbl. And headers.
The expensive part after the bolt on and in's are the heads. Leave them stock for 300 HP or port them well with 360 valves. The 318 will use more cam to get to 300HP than a 360 would and may push the power band area higher than you like.

Adding a 360 head lowers the comp ratio to much.

( Use a multi spark system to light the fire on ether engine.)

What is the gear ratio and tire size? Is a converter upgrade in the wallet?
What is the target of the build?
 
I have a set of 302 heads. While there good for dead stock, on your app. Or target goal, they would need to be ported out well with bigger valves.
IMO,'to exceed 3020 HP you'll need to port the heads. Slug replacement for better compression is a good idea but pricey.
 
302's are a good head. They are kind of a "closed chamber" which means they really help compression. If you are not going to replace pistons/or bore your 318, then the 302's are a great option. But, they still have small ports and valves, which means if you want good upper end performance, you should have them ported and 360 valves installed. This is a route many choose. You can get the same results several different ways. These are common on 318's from '85-91. Cost and availability is what generally determines which route most people go.
 
Just remember, the stock 318 2bbl had a gross rating of 230 horsepower (this would be in like new condition). Just a 4bbl with good dual exhaust should get it up to about 250-260. Headers another 15, A stock 340 type cam (.455 lift) will add approx. 30 putting you around 300 (timed and tuned right). But, once you have a 4bbl, a little healthier cam and headers, the heads will really make a difference. A good set of heads at this point can add another 40 hp, putting you close to 340-350. Last, I've bolted 340 heads and 360 heads on stock block 318's, and have always gained performance. Yes, you loose a some compression, but flow will ALWAYS trump compression. If you cut the 360 heads .040, they will work very well on a stock block 318. Many ways to the same destination :)
 
yeah, build the teen and be happy with 325-350, instead of spending far more to also purchase an engine to go higher.
 
I was in the same boat as you, but I opted to go bigger, so I found an LA 360. Originally I was going to just drop it in because it ran well and had low miles. Well things snowballed, now I have a brand new motor...

Its been bored .30 over, comp XE268H cam, edelbrock heads, weiand intake, new holley carb. Should be high 300s to low 400s, hard to say, Ill be firing it up in a few weeks so I don't even know how well it runs yet.
 
Thanks for the input guys. Now I plan on doing the KB Pistons for sure I just need to decide if I want to add 360 LA heads or find some 302 heads. Since I'm going with the KB pistons what would I need to do for porting/milling as far as heads go?
 
If you're going with changing the pistons the. You don't need to mill the heads. You will need to ports them and maybe look at going to bigger valves. With all that said and the money spent on first buying the 302 or 308 heads then rebuild them port upgrade to bigger valves, you'd be better off buy a set of aftermarket heads. Based off you goal and to keep cost down, go with a set of RHS heads and get the version with the 2.02 intake 1.60 exhaust.
 
1970Duster said:
If you're going with changing the pistons the. You don't need to mill the heads. You will need to ports them and maybe look at going to bigger valves. With all that said and the money spent on first buying the 302 or 308 heads then rebuild them port upgrade to bigger valves, you'd be better off buy a set of aftermarket heads. Based off you goal and to keep cost down, go with a set of RHS heads and get the version with the 2.02 intake 1.60 exhaust.
Click to expand...

Where is the best place to ?get a set of those heads?
 
Indy sells RHS heads. But the intake valve (2.02) might be a little shrouded since the 318 bore is less than 4.00 inches.
 
What kind of money you willing to spend ? A 318 can be turned into quite a screamer . I had a 318 back in the day , it was fun shutting down 350 400 and 396 Chevs and Potomacs with a little 318 .
 
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