SB 318 Wanting to build for a 67 Dart GT

[Hendogg]

Ok A buddy of mine has a 1967 Dodge Dart Gt that is missing the 273 that it come with but the rest is all there.. And I can get the old car for like $1000 and is a bucket seat console car.. I have a 318 that is 60 over that I would like to know more about.. Here is the Numbers off of the motor and the heads.. If any one can tell me a little more about it that would be grate.. The motor numbers are as fallow 4006730-318-12 with a date of 11-12-70 and the numbers on both heads are 4323302 and 284 with a big 5 next to the 284.. I know that the motor is 60 over with a 10-10 crank But not shore what pistons are in it.. The brand that is.. Are the heads a good set or would i need a different set. And what would be a good cam for a 60 over 318? It had an older holly hi rise intack on it when i got it and ran good the carb messed up and washed the rings out of it I think.. I was thinking about doing a re ring and bearing and gaskets and running it..The car will be a street car and has a 727 and an 8.75 with 3.23 sure grip.. Or would i just be better off going with a big block.. Thanks for all the help and im put.. I will get the heads off to give a pic of the pistons And the number that is on them..

 

[rumblefish360]

Are the heads a good set or would i need a different set. And what would be a good cam for a 60 over 318? It had an older holly hi rise intack on it when i got it and ran good the carb messed up and washed the rings out of it I think.. I was thinking about doing a re ring and bearing and gaskets and running it..The car will be a street car and has a 727 and an 8.75 with 3.23 sure grip.. Or would i just be better off going with a big block.. Thanks for all the help and im put.. I will get the heads off to give a pic of the pistons And the number that is on them.

Your more worried over nothing really. This is an easy "to do thing."

A re-ring job and gasket kit is inexpensive to do. Miles ahead of the big block.
IMO, the big block is way more expensive to do since a lot of stuff has to be changed out starting with the tranny, and maybe the rear end, then brakes etc..... the list rolls on.

IDK about the casting numbers exactly for the heads. Sounds like 2 different heads. I do not have my book in front of me, so, as a basic, they all flow the same within a few cfm. no need to change them out for a Mello geared driver.

A good cam depends a lot on what you want out/from the car. I like a cam of approx. these duration @ .050 specs; 216*/228* give or take 2* on either side. On a 110 or 112 C-line.
My Crane cam I used. An excellent driver with good response and power. Mello idle and good mileage.;
http://www.cranecams.com/product/cart.php?m=product_detail&p=23812

Comp equal; http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=626&sb=2

Lunati's equal; http://www.lunatipower.com/Product.aspx?id=2342&gid=297

I'm sorry to report that the carb did not mess up the engine but the way the carb was tuned by the last person to touch it .. or not... allowed the carb to run rich beyond Donald Trump and killed the engine. IMO, IF you do not have skill to do this tuning chore, find someone willing to teach you, grab a book and a great help is a simple 02 sensor and gauge to show you rich or lean conditions. Edelbrock makes a simple and inexpensive unit to use.

Find out how deep the pistons are in the hole. This, times (Multiply) the measurements of the head gasket and cc amount of the head will give you the compression ratio.
This would be great to know.


Running headers? A higher stall converter than stock? Anything else?

 

[Hendogg]

I don't want to sound like a Dummy here.. But is there a way to tell what cc the head is buy the numbers on the head? Both heads have the same number on them 4323302 and 284.. I've been running mopar for about 10 years and am on 2 or 3 different mopar sites and ant found 1 person that could tell me how to tell the difference between the heads..

The thing I don't know about heads is I see pistons listed all the time that say 9 to 1 with this head or 10.5 to 1 with this head and so on.. Same piston just different heads.. May Dad has been mopar all his life from racing to big street car's and can't tell me a thing about the different heads..

I was planing on just re ringing this motor and all new gaskets and seals And re-lapin the valves.. The car has headers in it and 2.5in ex and I want to say it has a 2500 stall converter in it.. I was thinking about going with Roller rockers but don't Know the difference between the 1.5 and the 1.6??

And I'm sorry about my post being so long.. I just ant real good with words.. I may not be the Smartest crayon in the box, But I am the brightest.. LoL

 

[Robbie2734]

SMALLBLOCK

67-75 318 2536030
76-79 318 4006730
80-83 318 4104230

71-74 360 3418496
75 360 3870230
76-80 360 4006830
I did a little research and came up with 76-79 318 for those numbers on the motor. You have "302 swirl port" heads from the numbers you gave and they are great for that motor. Go with your plan, maybe replace the timing chain and oil pump too. X2 on Rumblefish's cam, it should run strong. You'll need to replace the stock pistons to get above 9-1 CR, that would mean rebalancing the rotating assembly. While you have it apart check the bearings too. I run a 727 in my cuda with a 318, my opinion is use the 904 instead. It will be better off the line. I'm getting ready to replace my 318 with a 360 and I'm going back to a 4spd. That 318 would be fun with a 4spd, but thats a lot of work to do on a auto car. Check out this link for more info on the heads...http://www.1962to1965mopar.ornocar.org/ml-pitchercastingheadarticle.html

 

[cudamark]

Yeah, I think you're misreading the casting number....probably the last digit is a 6 or 8. The first thing to do is to make sure the block will clean with just a hone. Unless you have a real thick walled block, you're at the stock limit when it comes to boring. The 302 casting heads will work fine. Double check to see that you have a 727 as the stock transmission that year was a 904. If it turns out that it's the original 904, you'll need to get a reducing bushing for the end of the crankshaft to center the small snout on the stock converter. If you plan to do anything but putt around, I would consider going through the transmission and make upgrades, depending on the horsepower you end up with. If you plan to use regular pump gas, keep the 9:1 pistons.

 

[Salty Dog]

In order to find out the cc amount of the head, you will need a small amount of grease to seal up a small plexi-glass square to cover the entire chamber so you can fill it with a burret (SP?) that has cc marks to note how much liquid went into the chamber.

I searched Summit for this, in general page; http://www.summitracing.com/search/.../Part-Type/Cylinder-Head-CC-Kits/?Ns=Rank|Asc

Rocker ratio is thecam lobe lift multiplied by the ratio of the raocker to give enhanced lift at the valve.

So if a cam has a lobe lift of .333, at trhe valve with a 1.5 rocker is a math problem that looks like this;

.333 X 1.5 = .499 (.4995 actual) and a 1.6 rocker will equal .532 (.5328 actual)
Being able to see the difference in the rockers isn't so easy. Expriance would help, but the point of the contact of the pushrod to the adjuster is moved in slightly closer to the mounting point of the rocker on the shaft.

A higher ratio will not only give extra lift, but it will ever so slightly in a most meager way, increase the size (Duration) of the cam. The general 2* larger seems to be what everyone agree's apon. Who am I to argue?)
But the real treat comes in with the increased intencity of the cam.

Opening and closing the valves quicker is a key thing in making more power.
just do not forget that the increased lift almost allways requires new valve springs to handle the increased lift. This is valve control, the biggest issue in making power. Do not skimp.
There is also a limit to increased ratio of the rocker. You can push it to far. Beyond the liftersabilty to work, retainer to guide clearance and of course.... do they make it? (Custom rockers are way expensive!!!!)

The fish gave some real good cam choices since you have a limited gear ratio.

 

[Hendogg]

SMALLBLOCK
Check out this link for more info on the heads...http://www.1962to1965mopar.ornocar.org/ml-pitchercastingheadarticle.html

That is a Good wright up on the different heads.. Buy the way they talked the 302 swirl port design were a closed (heart-shaped) combustion chamber and had a average of 62cc in volume..
And they came with a dished piston to keep the compression ratio from being too high.
I bet that's why the motor ran so good before the carb messed up, Because the pistons in it was not Dished they were flat tops with valve reliefs.. The motor had maybe 15K miles on it since it was built and bored 60 over. I got the truck off of a buddy and he had just built it. Would just ask him what all was put in it bet he's not with us any more..
The reason we pulled it was kaz it started using oil and smoking.. And I got a good deal on a 28K 413 and trans out of a Winnebago and it was going in a BIG 4x4 truck.. So the motor has just been seating in the shop..

 

[Hendogg]

And I Sean where it said that with just some porting you can get these numbers out of the 302 swirl port heads.. The Mopar Engines book says that the home porter can expect improvements from 5-10 HP, but that the potential exists to get 50 additional HP out of the 302 heads..
They sound like a really good set of heads.. I wish I had the money to make around 350-400 hp out of it.. I talked to my buddy and it is a 727 trans with a B&M 2000 stall converter..

 

[cudamark]

That is a Good wright up on the different heads.. Buy the way they talked the 302 swirl port design were a closed (heart-shaped) combustion chamber and had a average of 62cc in volume..
And they came with a dished piston to keep the compression ratio from being too high.
I bet that's why the motor ran so good before the carb messed up, Because the pistons in it was not Dished they were flat tops with valve reliefs.. The motor had maybe 15K miles on it since it was built and bored 60 over. I got the truck off of a buddy and he had just built it. Would just ask him what all was put in it bet he's not with us any more..
The reason we pulled it was kaz it started using oil and smoking.. And I got a good deal on a 28K 413 and trans out of a Winnebago and it was going in a BIG 4x4 truck.. So the motor has just been seating in the shop..

That industrial 413 is little more than a boat anchor. Individual parts for that thing are getting to be impossible to find.

 

[Hendogg]

That industrial 413 is little more than a boat anchor. Individual parts for that thing are getting to be impossible to find.

O I know what you mean I broke the power steering mount on it getting it out of the winabago and have no power steering on it now.. But I think it is a good motor.. We pull the pan to put the one on where it would fit in the truck and it has a steel crank.. And the thing don't have a problem spinning all for of the 52's that's on the mud truck that it's in.. And buy a book that I have it came with like 225 hp and like 540 tq if I looked at it right buy the numbers on the motor and buy the book.. I know it has a 1150 cc holly carb on it.. But it does way a hole lot I will give you that.. It came out of a 1970 60ft motor home that had tandem axels under it..