318 DQ's

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tsa_035

tsa_035

72 Plymouth Duster
Joined
Feb 11, 2010
Messages
57
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8
Location
Santa Clarita, CA
Hey everyone so I have some really dumb questions about my 318.... It's the matching number for my 72 Duster...

I have completely gutted the motor and am waiting to take it to the machine shop, she has never been rebuilt before. The machine shop was going to deck it for me and do all the machine work. I will be adding a set of Eddy heads, air gap and running the Mopar .509 cam.
  1. Is it worth it to deck the block? (I have read the 273 decking forum and still have mixed feelings)
  2. I am thinking of throwing in a forged crank. I want this motor to last a while and pass it down to the kiddo someday. Is the forged crank really any better?
The list continued in my head but I totally forgot! Thanks again for all your help and advice in advance!!!
 
A nicely prepped crank including a good balance job will make a cast crank in a 318 live forever.
Unless all of a sudden you want 500HP out of it. Mopar cranks were good from the start, so you
should be fine.
 
tsa_035 said:
Hey everyone so I have some really dumb questions about my 318.... It's the matching number for my 72 Duster...

I have completely gutted the motor and am waiting to take it to the machine shop, she has never been rebuilt before. The machine shop was going to deck it for me and do all the machine work. I will be adding a set of Eddy heads, air gap and running the Mopar .509 cam.
  1. Is it worth it to deck the block? (I have read the 273 decking forum and still have mixed feelings)
  2. I am thinking of throwing in a forged crank. I want this motor to last a while and pass it down to the kiddo someday. Is the forged crank really any better?
The list continued in my head but I totally forgot! Thanks again for all your help and advice in advance!!!
Click to expand...

I would only deck the block to clean up the head surfaces to be flat and smooth... If you want to increase the compression, buy a set of 10.5 compression pistons and throw on a set of 340/360 heads, you will end up at 9.2 compression....

I ran a 72 318 up to 500,000 on a daily driver with the stock cast crank... No need for forged if you are just using it for street driving/cruising...
 
tsa_035 said:
Hey everyone so I have some really dumb questions about my 318.... It's the matching number for my 72 Duster...

I have completely gutted the motor and am waiting to take it to the machine shop, she has never been rebuilt before. The machine shop was going to deck it for me and do all the machine work. I will be adding a set of Eddy heads, air gap and running the Mopar .509 cam.
  1. Is it worth it to deck the block? (I have read the 273 decking forum and still have mixed feelings)
  2. I am thinking of throwing in a forged crank. I want this motor to last a while and pass it down to the kiddo someday. Is the forged crank really any better?
The list continued in my head but I totally forgot! Thanks again for all your help and advice in advance!!!
Click to expand...

The mopar .509" am is pretty big... What else are you doing to it for that cam????
 
I would recommend around 10:1 CR and a 3K stall converter with min. 3:23 rear gears with that cam. 65'
 
tsa_035 said:
Hey everyone so I have some really dumb questions about my 318.... It's the matching number for my 72 Duster...

I have completely gutted the motor and am waiting to take it to the machine shop, she has never been rebuilt before. The machine shop was going to deck it for me and do all the machine work. I will be adding a set of Eddy heads, air gap and running the Mopar .509 cam.
  1. Is it worth it to deck the block? (I have read the 273 decking forum and still have mixed feelings)
  2. I am thinking of throwing in a forged crank. I want this motor to last a while and pass it down to the kiddo someday. Is the forged crank really any better?
The list continued in my head but I totally forgot! Thanks again for all your help and advice in advance!!!
Click to expand...

For starters......get a piece of paper and write your list down, then all you have to do is remember where the piece of paper is......taping to the inside of the windshield is one possibility.

If the decking operation is "decking to square", then yes, it is a good idea..........what pistons are you going to use? Knowing what pistons you are going to use; as in what is their compression height, dome (if any), will also affect how much of a cut when you deck. That .509 cam is gonna want some compression and some gear, and some stall in the converter for it to work well; get the combination right and the car will be an a$$ ripper and you will never get tired of telling people it's "just" a 318.

As already stated don't worry about a forged crank shaft; have yours cleaned, magnafluxed and balanced and you'll be good to go.

Good luck!
 
tsa_035 said:
  1. Is it worth it to deck the block? (I have read the 273 decking forum and still have mixed feelings)
  2. I am thinking of throwing in a forged crank. I want this motor to last a while and pass it down to the kiddo someday. Is the forged crank really any better?
The list continued in my head but I totally forgot! Thanks again for all your help and advice in advance!!!
Click to expand...

1; Yes, just enough to make it flat and no more unless your after making the pistons sit flush with the deck.

2; No. On the street it is only bragging rights. Which don’t mean a thing unless your expoliting the hp level where it is needed. Brag about it with even a 450 hp 318 and look Silly. But I’m sure there is someone out there that will be impressed!
 
Don't worry a bit about the steel crank at your power level. Totally a waste of money and not necessary. As far as decking the block. that id worth every penny. Make sure it is decked to factory spec and also decked parallel to the crankshaft center line. That 509 cam is a whopper john for a 318, but I like your style. If you already have it, what the hell.......stab it in. BUT advance it down around 100 ICL. Maybe even 98. That will pick up some otherwise lost bottom end torque. That thing will sound really nasty.
 
However, on the other hand, if you already have a forged crank, then yeah you get thrown in, why not?
 
I would not spend money on cutting the deck of the block unless you are squaring the deck......alot fast cars out there with cast cranks

I would use a smaller cam in a 318...but advancing it will help....and if you are advancing it 8 degrees or so...check you intake valve to piston clearance..
 
With aluminum heads, I ran that 292/108 on 11.3 Scr on 87E10, in my 367 with a manual trans.
IMHO You can hardly make enough compression in a 318 to properly run that cam.... ON THE STREET.

So would I deck it? I had to.
If you don't get the pistons to zero or slightly positive in deck height in SOME way , you are gonna need a heck of a TC and fairly steep gears to pull it off, AND you might as well buy stock in a filling station. At zero, the best you can get with 63cc heads is about 9.6Scr, and by the time it's buttoned up, you're looking at around 140psi cylinder pressure. If you try to run this with a stock TC and street gears you will be sorely disappointed. The bottom end will feel softer than silly-putty.
With aluminum heads, I have run over 185psi on 87E10. That makes pretty snappy engine.
But your 318 can't get there with 63cc heads.
Even if you had 58cc aluminum heads and used the .039 Gasket to set your Q and popped those flat-tops out of the holes .010, your Scr would still only come in around 10.1 tops, and the pressure might get up to 150psi, and the bottom would still be like warm peanut butter.
I strongly urge you to reconsider that cam.
 
AJ/FormS said:
With aluminum heads, I ran that 292/108 on 11.3 Scr on 87E10, in my 367 with a manual trans.
Click to expand...
Really?
IMHO You can hardly make enough compression in a 318 to properly run that cam.... ON THE STREET.
Click to expand...
Disagree, @ 11-1, your good to go.
Way good to go!


I strongly urge you to reconsider that cam.
Click to expand...
Agreed! Otherwise it is a lot of converter and gear
 
rumblefish360 said:
Really?

Disagree, @ 11-1, your good to go.
Way good to go!



Agreed! Otherwise it is a lot of converter and gear
Click to expand...
Sure but how can you make 11/1 with 63cc heads?
That's gonna take custom pistons, not flat-tops, and then you get into unusual chamber shapes

I see you read the beginning and end of my post, but it looks like you missed the meat and potatoes.
To get to 11/1 with a teener@ 3.94 bore would require a TOTAL chamber volume of 66.2cc,TOTAL. After setting the piston to head distance and setting the Valve to piston clearance, and the Q. That's a lotta machining. And the decks would want to be milled and the Line hone, and those expensive Eddies shaved,and a rebalance, and crap you couldda almost built two 360s by the time all is said Ndone.
 
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Well, for the most part your posts drone on and on with lots of dribble. There to long for my eyes to read.

11-1 on a teener?
I do 11-1 on a 360.
 
OP
I pulled that 292 out towards the end of the first summer cuz even in my 367, I felt the peanut-butter. And I had a clutch.
I went down to a 270/276/110 fast-rate/hi-lift, and had a ton more fun with that, and a bonus was the tremendous fuel mileage I was able to get out of her, now at 10.9Scr, and 185psi IIRC. The bottom-end was fierce.
 
AJ/FormS said:
Sure but how can you make 11/1 with 63cc heads?
That's gonna take custom pistons, not flat-tops, and then you get into unusual chamber shapes
Click to expand...
And this is a problem for you the internet star NOT building the engine?
Seems your a 318 hater. Perhaps you should move along to a 340/360 thread.
I see you read the beginning and end of my post, but it looks like you missed the meat and potatoes.
Click to expand...
I’d get it if you didn’t drone on.
Get it done!
Short and sweet!
Quality not quantity!
To get to 11/1 with a teener@ 3.94 bore would require a TOTAL chamber volume of 66.2cc,TOTAL. After setting the piston to head distance and setting the Valve to piston.....
Click to expand...
All part of the fun building engines.
Now why would I have to tell you that?
Build what you wish, not what others tell you to or what they think is better or more cost effective or.......
But you’ll just brow beat people into submission.
 
AJ/FormS said:
OP
I pulled that 292 out towards the end of the first summer cuz even in my 367, I felt the peanut-butter. And I had a clutch.
I went down to a 270/276/110 fast-rate/hi-lift, and had a ton more fun with that, and a bonus was the tremendous fuel mileage I was able to get out of her, now at 10.9Scr, and 185psi IIRC. The bottom-end was fierce.
Click to expand...
Oh yea like this!
Oh wait! It’s a 360, nevermind. Doesn’t apply to a 318 but KD.
LMAO
But the lesson is there.
THINK!
 
AJ/FormS said:
It's called a stuppor,
Click to expand...
Yes! Correct! You put me into one. If you were reading out of the book, I would fall asleep easy! It reminds me of the time my wife used to read her medical books while studying for her nursing degree to my son. He would fall fast asleep!
 
I am not a teener buster. They are the perfect size for most street A-bodies, when built correctly for the application. But I see a guy dreaming of 360 power at 6400 plus rpm, and I have to speak up, because at 2500rpm it won't hardly get out of it's own way.
So then you have to bandaid it up with a 3500+ TC and better than 3.91s. Now you're into it for mega bucks, and all you can do is drive it from one filling station to the next. That get's old real fast.
Been there done that, never again.
But you don't seem to care about OPs wallet. Spend, spend, spend
 
The OP’s wallet and his performance perameters as well as what he is willing to live with, or not are his biz and Prerogative. Not yours.

Due note that I have agreed with a lot of what you said starting with a smaller cam and IMO, a 9.0-1 to a 9.5-1 comp ratio would be a better all around package.

The big stall and gear set I mentioned already and thank you for reading that or did you forget you read it?
Admiring to bypassing it?

Wake up AJ!
 
Hey Everyone!!! Thank you for all the responses!!! I sure do have a lot of considerations.

Just for an FYI nothing is set in stone as of yet. Here is addtl info of the car as of right now. 904, 8 3/4 with 3.55 gears. Current motor in it the veh is 318 30 over with performer package...

As far as the list I found addtl threads that answered questions (pistons)... I do have addtl questions I am researching threads for info and if I cant find I will post a thread with it (fuel tank vs fuel cell's, dash modifications, electrical modifications, etc.) Sorry for all the questions. I know I have been a member for a while just never logged in to much!!!
 
I wouldn't waste my money on a 318 with the short stroke... you could have more fun with a stock 360.

Yeah.... I know... I'm a 318/273 hater.
 
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