318 build check from you experts

-
S

sefus

Well-Known Member
Joined
Jul 27, 2005
Messages
183
Reaction score
3
Location
Spokane, Wa
Rebuilding the stock 318 in a D100 and using a bunch of leftover parts from my dart that got upgraded along the way. Wanted to get couple of opinions though on just what to do with it. The truck will be on the street 99% of the rest of its life. We are buttoning up the lowering job, new brakes and shocks and whatnot on it now. It was my high school truck and my son will be driving in a few years so I figure get it close to decent and drive it a bit, then he can work on it and upgrade as he can afford to. With that in mind, I'm keeping the 318 - mostly because I have it - and it will have plenty of power but be mild enough to not get him into too much trouble. I'm thinking some KB 9.5:1 pistons, it does have newly rebuilt stock heads but I'd be ok with putting some aluminum on there since now's the time to do. I do have a Comp 425 lift at 252 I can put in. Dont know if that's too much cam for the stock heads though. Will reuse an edel air gap intake and have a couple different 650 and 750 carbs, plus full MSD setup to use.

So I'm hoping you guys can help steer me on the cam/heads idea, what converter to look at (I have no idea what gears it has and the rear tires are 275/60/15's), and if anything is really standing out as a not workable combination. I figure if I go aluminum heads I could up the rocker ratio to 1.6's and increase the compression to 10:1 but then that cam may not be ideal... see where my head starts spinning...

Thoughts?
 
Spokane/Elevation

Spokane is located on the Spokane River in eastern Washington at an elevation of 1,843 feet

Do yourself a favor and go find a 360/5.9

Or else prepare for a lotta rear gear and at least a 2800 stall. Both of which at your weight will kill fuel economy.
Your 318 will not get much out of alloy heads; but they will be killer on a 360, in your application..

Here's why; at your elevation, getting the pressure up with a 318 is very difficult and expensive.
A) Suppose you get it up to 9.0Scr, and suppose that your 252 cam has an Ica of 54*. The end result might be 150psi with an
Effective Dcr of 7.5@ V/P of 121 a pretty weak bottom end
B) Suppose you get her up to 9.8 with closed chamber heads and a tight-Q of .040 or so. Now the pressure might be 164,This is about the limit for 91 gas and iron heads.
Effective Dcr is looking like 8.0 @V/P of 131, still a weak VP.
C) ok but suppose that lil 252 cam doesn't cut it, lets try the 268/276/114, 340 cam that everybody is always bragging on. At 9.8Scr and an Ica of 64*, the pressure falls to 149psi, the Effective Dcr to 7.45 and the VP to a less than mediocre 110. And this is at Scr of 9.8! This is so doggy off the line, that you will hate it. To get the VP back up to a reasonable/but still low 131, the Scr needs to be 11.2; that ain't happening. To get 11.2 at 3.93 bore the Total chamber volume would have to be reduced to 64.6cc. Since you will have to run the .039 FelPro gaskets(8.8cc) to deal with the pressure, and the Eddys are 63cc, you are already up to 71.8cc!, yeah so custom pistons it has to be, and probably machining of the decks and a matching cut off the intake; read very expensive. With iron heads you would be dead in the water

D) Ok but the 360 with KB107s, Edelbrock alloy heads, and an .028 gasket, will come in very close to 10.7Scr, with no machining besides for the pistons, read cheap. Now; your pressure with that 252* cam, jumps to 184psi, your
Effective Dcr to 8.75@ a V/P of 156, which is funtastic.

So what you didn't spend on milling stuff, you can put towards a 360/5.9 core, AND you can keep whatever gears and stall is currently in the truck, for an even bigger savings,
AND you can run 87E10 gas for a lifetime of saving money.

Because of the very high V/P,(156), and the alloy heads, you could theoretically run a bigger cam now.
I suggest a 268/276/108 with an Ica of 60*. This will only sacrifice 2.5psi so still 174.5, the Effective Dcr drops to 8.76, and V/P only falls to 141, still a ton of fun. I would not run any bigger on the street.
I have, in the past run about this same pressure/VP combo at 930 feet.Yes on 87E10.
The 268 cam is about 2.5 sizes bigger than the 252, so the powerpeak has moved up about 500 rpm from something like 4500 to 5000. With the 275s (88" roll-out) you can use 3.23s with this and hit 60=6200/6300 10% slip........ still in first gear,lol. and when cruising 65=2520@ zero slip, perhaps 2600 on the tach.
Read about V/P here;
V/P Index Calculation
 
Last edited:
I call BS and my favorite 318 hater is back I see. Instead of helping you with what ya got, he’s asking you to spend more money. Not that a larger engine is a good route, but why stop at a 5.9 and go right to the top with a stroked 400/440?

Let’s get to the serious part of this and start with your cam. It is a Comp 252 advertised duration with .425 lift. This is barely the first step above a stock cam and waaaaay smaller than the OE 340/360 performance cam.
WAY SMALLER!

It is not to much for the stock heads. Just use the recommended spring from Comp or an equal. Keep the stock heads. Aluminum would be a waste of money and so would 1.6 rockers. Just reuse the factory rocker.

Use those 9.5-1 pistons! Measure them in the bore on how far down they are along with the cylinder head cc amount. Then the gasket size. Thickness and bore.

Go here and enter the numbers for hour static ratio.
Compression Ratio Calculator - Wallace Racing
Remember your can use a thicker gasket to lower or thinner to raise the compression. 9.5-1 actual or lower is good.
I would certainly use the 650 carb on top of the rpm.

On a converter, I’d bet a G that the stock converter will work perfectly but you’ll need to know the gears & the tire size along with all the engine stuff. So write that down when you call up a custom converter place like Dynamic, Pro Torque, Ultimate, etc...

OH! PS, visit this guys you tube channel.
https://m.youtube.com/results?search_query=318+will+run
 
Rumble, I think you have a hard time reading between the lines.
OP asked for thoughts
OP mentioned the alloy heads.
OP mentioned new pistons.
The rods, as you know are the same between the LAs and sorta worthless in a rebuild.
OP wants a new cam
OP has an AG and several carbs.
The truck is pushing 3800 pounds and the tires will be 28s
So Come on,
The only part he might reuse
"mostly because he has it", his words,
is the worthless 318 block.
But worst of all Spokane is at 1843 ft elevation.
Why would you sacrifice something like 150 to 200 horsepower just to keep the stinking 318 block?

Take off your blinders once in a while.
 
Last edited:
What parts do you have?
What is the budget?
What is the goal?
What year engine?
If you are buying pistons,shoot for 9.8 to 10.2.
Cam is too small,look for a 480ish,torque cam.
Advance the cam 2 to 4 degrees.
.028-.038 head gasket,aluminum heads a plus,or use later 302 heads,360 heads.
 
We should all just throw everything we own in the dumpster and start building 500” fuel Hemis. Everything else is just a waste of time.......
To OP, I say slam that thing together on the cheap with what you got on hand. Let the boy cut his teeth in it and then he can spend his coin on it however he likes. If we spent as much time wrenching as we do overthinking these things, there’d be a lot more hot rods running the streets.
 
64mopar said:
What parts do you have?
Rebuilt 318 heads to stock specs, carb, intake, distributor, ignition, headers, cam that's sounding like its too small and a block that needs to get refreshed
What is the budget?
Kinda don't have one but I'm not taking this truck too seriously either
What is the goal?
Fun for me, a muscle truck for the boy to learn hot rodding on. Street manners.
What year engine?
74
If you are buying pistons,shoot for 9.8 to 10.2.
Copy. will go for the 10:1's
Cam is too small,look for a 480ish,torque cam.
Advance the cam 2 to 4 degrees.
Sounds good.
.028-.038 head gasket,aluminum heads a plus,or use later 302 heads,360 heads.
Click to expand...

Thanks fellas. My Dart has gone through upgrade after upgrade without ever really getting on the road for too many years so I'm trying to keep this one as simple as I can, but when you are redoing things, why not shoot for efficiency, right?

I do appreciate the thoughts on going to a 360 and of course it crossed my mind plenty of times. I never thought about the altitude adjustments.

I kind of just don't mind this being a small, smallblock rig. I have it and don't have to go source and pull a 360, rebuild that, not use some of the parts Ive collected along the way, change the converter, etc.
 
Did the same with 302 stock valve heads with a comp XE256H cam and 625 carb. Was in a truck with 3.55 gear. High idle vacuum, great off idle acceleration and surprising top end power. We beat the heck out of this towing, working and slide in old heavy camper, slightly ported stock heads did great.
 
Don't hope for miracles when you're not putting much into it. I'm sure it will run fine though , cam seems decent for what you're doing.
 
AJ/FormS said:
Rumble, I think you have a hard time reading between the lines.
Click to expand...
No I don’t and I answered his thoughts as quoted by you below and the OP.
OP asked for thoughts
Click to expand...
I gave my thoughts. Oooo nooooo!!!!
OP mentioned the alloy heads.
Click to expand...
No chit Sherlock!!! I even addressed it!
Ooooo noooooo
OP mentioned new pistons.
The rods, as you know are the same between the LAs and sorta worthless in a rebuild.
OP wants a new cam
OP has an AG and several carbs.
The truck is pushing 3800 pounds and the tires will be 28s
Click to expand...
And OH my LORD!! I addressed the rest of your quote as well! Holy smackers!!!

I guess AJ needs to take his blinders off!


The only part he might reuse
"mostly because he has it",
Click to expand...
That’s not what I read and rechecked twice over to be sure. Perhaps, just perhaps, you should take your blinders off and read what is actually there instead of ASSUME!! You assumed he is possibly reusing the 318. He says something else & it’s not what you wrote.

Oh! You are a 318 hater. Your the one who called it... what was it now???
Ahhh yes, “Is the worthless 318 block.”
That is exactly what you wrote hater.

Truly AJ, reading is fundamental!

But worst of all Spokane is at 1843 ft elevation.
Why would you sacrifice something like 150 to 200 horsepower just to keep the stinking 318 block?
.
Click to expand...

Wait a second here. Your telling me that the 318 is going to be down 150 to 200 HP with the parts he has to build it on right now at the ready.

AJ! Stop smoking crack!
Your are insane! But I still love ya brother.

With the parts he has now, I don’t see an issue for a nice daily driver that will have a small but reasonable upgrade in power over the stock engine.

And why would he need a numeric high gears and a 2800 converter?
I don’t know for sure but the OE didn’t do that.
Ya wanna compare a stock cam vs the Comp 252?
I’ll accept your cam vs cam results.
 
Last edited:
Oh, thanks again for helping a MoPar brother out building his engine.



Oh wait, you didn’t!!!!

Never mind... drive on through....

Now if he said help me hot rod my truck with a small block.....
I’d be on board.
 
I said worthless for two reasons;
1) because, that could very well be the only part of his 318long that gets reused. and
2) 318 blocks are like dirt; they are everywhere, underfoot, and everybody has one in the shed taking up valuable space, that they would love to give away. I probably have, shoot I don't even remember how many, maybe 8 to 10 of them, and I would give every one of them away.
If yur gonna spend $3000 to $5000 on a rebuild, why oh why would you not spend a $100 or perhaps $200 on a 360/5.9M core? Especially to motivate a nearly 4000 pound truck.
The 318TC compensation alone will cost more than that.
IDK how many times I gotta say this; a 318 is fine at 10 pounds per cube,at sealevel, but by the time you get to 3800/318=11.95 pounds per cube,at 1843 ft elevation the build is going seriously away from streetable. I mean we're talking 3800/10 pounds per horsepower= 380 hp, and in a 318, the bottom end is going away fast. Whereas an alloy headed 360 is just getting started. I mean they fall together at that, with a tiny cam, and have gobs of low-rpm power.
But Hey
I'm getting used to you beating me up, so carry on.
 
AJ/FormS said:
I said worthless for two reasons;
1) because, that could very well be the only part of his 318long that gets reused. and
2) 318 blocks are like dirt; they are everywhere, underfoot, and everybody has one in the shed taking up valuable space, that they would love to give away. I probably have, shoot I don't even remember how many, maybe 8 to 10 of them, and I would give every one of them away.
If yur gonna spend $3000 to $5000 on a rebuild, why oh why would you not spend a $100 or perhaps $200 on a 360/5.9M core? Especially to motivate a nearly 4000 pound truck.
The 318TC compensation alone will cost more than that.
IDK how many times I gotta say this; a 318 is fine at 10 pounds per cube,at sealevel, but by the time you get to 3800/318=11.95 pounds per cube,at 1843 ft elevation the build is going seriously away from streetable. I mean we're talking 3800/10 pounds per horsepower= 380 hp, and in a 318, the bottom end is going away fast. Whereas an alloy headed 360 is just getting started. I mean they fall together at that, with a tiny cam, and have gobs of low-rpm power.
But Hey
I'm getting used to you beating me up, so carry on.
Click to expand...
Sorry, your not trying to convince me are you?
I just wanna be clear in this. The above post was a response to me.
 
sefus said:
I'm hoping you guys can help steer me on the cam/heads idea, what converter to look at (I have no idea what gears it has and the rear tires are 275/60/15's)
Click to expand...
Going to be hard to recommend a converter without knowing the Gear ratio and tire diameter. ...

I'm not the engine building expert that some of these guys are, so I'll just say that to me your combination sounds pretty good.
I have a mild 318 build in my '68 Barracuda and while it weighs less than a D100, it moves pretty good!

Keep us updated on your build!
The 318 is a great small block Mopar!

Jeff
 
AJ/FormS said:
I said worthless for two reasons;
1) because, that could very well be the only part of his 318long that gets reused. and
2) 318 blocks are like dirt; they are everywhere, underfoot, and everybody has one in the shed taking up valuable space, that they would love to give away. I probably have, shoot I don't even remember how many, maybe 8 to 10 of them, and I would give every one of them away.
If yur gonna spend $3000 to $5000 on a rebuild, why oh why would you not spend a $100 or perhaps $200 on a 360/5.9M core? Especially to motivate a nearly 4000 pound truck.
The 318TC compensation alone will cost more than that.
IDK how many times I gotta say this; a 318 is fine at 10 pounds per cube,at sealevel, but by the time you get to 3800/318=11.95 pounds per cube,at 1843 ft elevation the build is going seriously away from streetable. I mean we're talking 3800/10 pounds per horsepower= 380 hp, and in a 318, the bottom end is going away fast. Whereas an alloy headed 360 is just getting started. I mean they fall together at that, with a tiny cam, and have gobs of low-rpm power.
But Hey
I'm getting used to you beating me up, so carry on.
Click to expand...
Here is my old, tired, untouched long block 318 drug from a farmers field in a D150 long bed. Is it fast??? Naw.... Is it fun ??? I think so :)
 
really leaning towards going with Aluminum heads. If so, what cam would you recommend that will still be street manered but can take advantage of the better flow over the small valve irons? stick with 1.5 rockers or go 1.6s? Any converter change at this point?
 
sefus said:
really leaning towards going with Aluminum heads. If so, what cam would you recommend that will still be street manered but can take advantage of the better flow over the small valve irons? stick with 1.5 rockers or go 1.6s? Any converter change at this point?
Click to expand...
You haven’t even take advantage of the stock head and valve size. What ever cam you have in there now will operate better with better flowing heads.
 
SSG_Karg said:
We should all just throw everything we own in the dumpster and start building 500” fuel Hemis. Everything else is just a waste of time.......
To OP, I say slam that thing together on the cheap with what you got on hand. Let the boy cut his teeth in it and then he can spend his coin on it however he likes. If we spent as much time wrenching as we do overthinking these things, there’d be a lot more hot rods running the streets.
Click to expand...
Thank you
 
Look at it like this, being "on the cheap" has a time and place. In regards to the build, if what you have to work with is the end goal, go for it. But decide now. Building a 318 now only to swap out later to a 360 is a waste. The money sank into the 318 will end up sitting in the corner. I've done it...
 
OP, If you put that 318 together just to drive the car,ok. Don't get into "converting it" by using 340-360 heads,using aftermarket Pistons to bump compression etc. Most I do to a 318 is,cam 4 barrel and headers...everything else stock,heads and bottom end. This way not too much time and money invested into something that is generally around in abundance and given away traditionally.
 
You must log in or register to reply here.
-

Back
Top