1972 318 street build

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1969moparDART

1969moparDART

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Okay I'm putting together a virtual engine for now to get a rough price to build up to, so one of the thing I want is bore and stroke i think I'm only go .020 or .030 over with these pistons
Clevite MAHLE 2242007020: Piston 1968-2001 Small Block Chrysler V8 318ci (5.2L) with 3.93" Bore (+.020") | JEGS
or the identical ones that are .030. As for the stroke I'm not sure yet but I'm wanting a new crank because I don't want to get my original one machined down, so I need some suggesting and preferences for a crank. So that dos pistons and crank, what do we need to make those work together? Exactly I need connecting rods that will work with those pistons and crank which again I need some suggestions and preferences on those and also I would like why you prefer them to others. last but not least I haven't done many cams so I want to know you guys opinions and experiences with every cam you have had any personal experience with, not just hear say but actual experience.
Thanks in advance guys,
Thomas
 
1969moparDART said:
Okay I'm putting together a virtual engine for now to get a rough price to build up to, so one of the thing I want is bore and stroke i think I'm only go .020 or .030 over with these pistons
Clevite MAHLE 2242007020: Piston 1968-2001 Small Block Chrysler V8 318ci (5.2L) with 3.93" Bore (+.020") | JEGS
or the identical ones that are .030. As for the stroke I'm not sure yet but I'm wanting a new crank because I don't want to get my original one machined down, so I need some suggesting and preferences for a crank. So that dos pistons and crank, what do we need to make those work together? Exactly I need connecting rods that will work with those pistons and crank which again I need some suggestions and preferences on those and also I would like why you prefer them to others. last but not least I haven't done many cams so I want to know you guys opinions and experiences with every cam you have had any personal experience with, not just hear say but actual experience.
Thanks in advance guys,
Thomas
Click to expand...
Ah yes!
Building the perfect 318.
Looks like those pistons are for a MAgnum 318 and not a LA. They are probably different. There are scads of threads about it here on FABO. Here's a link to a 400 hp. teen that the magazines did years back. 318 Engine Build - A Parts Book 400HP 318 - Mopar Muscle Magazine
 
toolmanmike said:
Ah yes!
Building the perfect 318.
Looks like those pistons are for a MAgnum 318 and not a LA. They are probably different. There are scads of threads about it here on FABO. Here's a link to a 400 hp. teen that the magazines did years back. 318 Engine Build - A Parts Book 400HP 318 - Mopar Muscle Magazine
Click to expand...
how can you tell that they are for a magnum? and i dont really have the funds for the 400hp 318 lol i wish i could, i am also worried about to much torque in my dart as it is a unibody , so i guess thats another question how much torque is it gonna hold up to before it twists the body too much?
 
1969moparDART said:
how can you tell that they are for a magnum? and i dont really have the funds for the 400hp 318 lol i wish i could, i am also worried about to much torque in my dart as it is a unibody , so i guess thats another question how much torque is it gonna hold up to before it twists the body too much?
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Don't worry. The car will take much more than a 318 can put out. I suggest you poke around here and read threads before you start building. Knowledge is power.
 
There are as many suggestions and opinions as there are Mopars out there.
 
toolmanmike said:
Don't worry. The car will take much more than a 318 can put out. I suggest you poke around here and read threads before you start building. Knowledge is power.
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i kinda thought it would but people keep warning me of twisting my body so it had me kinda worried as for the research i definetly will as i am no where near ready to start building, thanks for the help thus far man
 
Those pistons are standard, plain-jane, cast 318 pistons.... meaning they will be standard 318 low compression with a stock stroke crank. If you put a decently large cam in with these pistons and a stock stroke, the low RPM torque will be crappy to non-existent, and that is not what is desired for standard street driving. That is the problem with these and any low compression pistons.

Let's back up and find out what you want to achieve with this:
  • 'Street' can mean a lot of things. Is this a daily driver, or a stout street cruiser? Or do you want something with a lot of HP? That will drive the direction of the parts selection.
  • I take it that by saying street, you are not intending on racing this?
  • Do you have a rough budget range?
  • Do you have any option to switch away from a 318 to a 360?
Is there some particular concern over turning down the present crank? Doing that is a perfectly normal and OK thing to do, even for high HP build.

The most common stroke option would be for 4" stroke. The minimal cost for a new 4" stroke crank is around $300-350. (Eagle brand.... some reports have been around of breaking such cast Eagle cranks but I don't know the full history there, so take it with a grain of salt.) The pistons to work with that and using the standard 6.123" long SBM rods are completely different. Here are some:
Chrysler Dodge Mopar 318 Flat Top Pistons | Campbell Enterprises

There may be some combinations of other pistons and Chevy rods that will work, but you will need to turn the new stroker crank down to 2.100" rod bearing journal size to work with the shorter Chevy rods (again, not a big deal). The Eagle catalog has a list of 2.100" journal Chevy rods; they mostly use .927" diameter piston pins, so they won't directly work with SBM pistons that use a .984" pin. That is typically the biggest challenge in finding alternate pistons for SBM's. And, there are not many stock pistons round of any type for the diameter range of the 318 bore. So the easy way is to spend the $$ and get the pistons like shown above with the right bore and pins, and the compression height set up for 4" stroke.

Once the piston/stroke combination is set, then the compression ratios can be calculated, and the heads and cam can be worked upon.
 
nm9stheham said:
Those pistons are standard, plain-jane, cast 318 pistons.... meaning they will be standard 318 low compression with a stock stroke crank. If you put a decently large cam in with these pistons and a stock stroke, the low RPM torque will be crappy to non-existent, and that is not what is desired for standard street driving. That is the problem with these and any low compression pistons.

Let's back up and find out what you want to achieve with this:
  • 'Street' can mean a lot of things. Is this a daily driver, or a stout street cruiser? Or do you want something with a lot of HP? That will drive the direction of the parts selection.
  • I take it that by saying street, you are not intending on racing this?
  • Do you have a rough budget range?
  • Do you have any option to switch away from a 318 to a 360?
Is there some particular concern over turning down the present crank? Doing that is a perfectly normal and OK thing to do, even for high HP build.

The most common stroke option would be for 4" stroke. The minimal cost for a new 4" stroke crank is around $300-350. (Eagle brand.... some reports have been around of breaking such cast Eagle cranks but I don't know the full history there, so take it with a grain of salt.) The pistons to work with that and using the standard 6.123" long SBM rods are completely different. Here are some:
Chrysler Dodge Mopar 318 Flat Top Pistons | Campbell Enterprises

There may be some combinations of other pistons and Chevy rods that will work, but you will need to turn the new stroker crank down to 2.100" rod bearing journal size to work with the shorter Chevy rods (again, not a big deal). The Eagle catalog has a list of 2.100" journal Chevy rods; they mostly use .927" diameter piston pins, so they won't directly work with SBM pistons that use a .984" pin. That is typically the biggest challenge in finding alternate pistons for SBM's. And, there are not many stock pistons round of any type for the diameter range of the 318 bore. So the easy way is to spend the $$ and get the pistons like shown above with the right bore and pins, and the compression height set up for 4" stroke.

Once the piston/stroke combination is set, then the compression ratios can be calculated, and the heads and cam can be worked upon.
Click to expand...
Woah there big fella. It seems the OP is a beginner. Don't overload him with technical "Chevy Rods" and the like.
 
nm9stheham said:
Those pistons are standard, plain-jane, cast 318 pistons.... meaning they will be standard 318 low compression with a stock stroke crank. If you put a decently large cam in with these pistons and a stock stroke, the low RPM torque will be crappy to non-existent, and that is not what is desired for standard street driving. That is the problem with these and any low compression pistons.

Let's back up and find out what you want to achieve with this:
  • 'Street' can mean a lot of things. Is this a daily driver, or a stout street cruiser? Or do you want something with a lot of HP? That will drive the direction of the parts selection.
  • I take it that by saying street, you are not intending on racing this?
  • Do you have a rough budget range?
  • Do you have any option to switch away from a 318 to a 360?
Is there some particular concern over turning down the present crank? Doing that is a perfectly normal and OK thing to do, even for high HP build.
Click to expand...
she will be a stout daily driver as my end goal
and no i dont plan on actually racing a track but steet racing happens alot with me and my buddies lol
budget im hoping to keep at 3000ish more or less as needed because i know you car is only as fast as you right hand can buy parts lol
and i dont have anything against a 360 but i have 2 spare 318 blocks so they are money i dont have to spend
turnng down the stock crank just makes it weaker and i know im not making enough power to matter but i would rather have something that was made for what i want rather than have mine cut down, but push comes to shove or if its cheaper i may have it cut down anyway but i was just wanting options and research for now, and no offence but i will never put a chevy part on my car.
thanks for the input bro
 
quick question does anybody know roughly what my CI will be with a 4 inch stroke and .030 over bore, and to add to my original plan im gonna go .030 over and im looking at either 3.79'' stroke or 4.00'' stroke, im sorry if i change my ides to much im just looking for information because im 17 and i understand engines and can build them stock all day long but i have never done any real performance
 
Don't worry about turning down your 318 crank- compared to a chevy they are super strong- lots of room
but if you have two cores chances are that one crank is good to go with a good cleaning and maybe polish
do not spend money where you do not have to
Stock rods- save some money and use SPS (same as Mopar performance) rod bolts but do do a quality rebuild- or not with low compression stock pistons and a mild hyd cam
forget studs for the bloc and heads
figure out which gas you are going to run on a daily basis and some here will dial in your compression goal for both cast iron and al heads
do not think about cam too much till you get compression dialed in as cam must match compresion, gears, converter, weight and your right foot and gas mileage goals- (which with a Holly double pumper will be abysmal so forget the eye candy/ bragging rights)
if you do go with the lower than stock pistons keep the cam stock duration but more lift
big cam and low compression is no fun with stock street gears/ converter
if you want a race car build a race car
now after you take the heads off and before removing the pistons measure how far down the bore they are at all four corners with the extension that comes out of your dial calipers and write it down and post it here
you can weigh a stock piston and if close and you use crank and rods as a set you will not have to pay for a balance job
for your application stock 4 bbl manifold and carb will work as well (not quite as light is the only advantage to aluminum dual plane without spending lots of money)
spend your money on first good headers- second good heads (or vice versa) put off cam till you get compression, headers, and heads figured out
The cast iron head exhaust needs a different cam (longer exhaust) and headers (smaller dia)than an aluminum head or the aftermarket "EQ head or the late 308 head))
Virtual build- stick with it
measure twice cut once
do a spreadsheet to track your virtual costs/ benefits
YOU CAN GET ANY COMPRESSION YOU WANT
Track Head CC's on your spread sheet and piston CC's
answer the gas question
 
1969moparDART said:
quick question does anybody know roughly what my CI will be with a 4 inch stroke and .030 over bore, and to add to my original plan im gonna go .030 over and im looking at either 3.79'' stroke or 4.00'' stroke, im sorry if i change my ides to much im just looking for information because im 17 and i understand engines and can build them stock all day long but i have never done any real performance
Click to expand...
If you decide to go with the 4" stroke, I have a brand new set of after market rods I can sell you for a good price. these rods were for a project that has gone away. I'm in S. Texas treblig
 
You may want to consider looking at suspension, tires and brakes before go-fast stuff.

Ask anyone who rides a sport bike.

There is a whole section here on suspension and a lot of knowledge available.
 
1969moparDART said:
quick question does anybody know roughly what my CI will be with a 4 inch stroke and .030 over bore, and to add to my original plan im gonna go .030 over and im looking at either 3.79'' stroke or 4.00'' stroke, im sorry if i change my ides to much im just looking for information because im 17 and i understand engines and can build them stock all day long but i have never done any real performance
Click to expand...
390.2
 
Wyrmrider said:
Don't worry about turning down your 318 crank- compared to a chevy they are super strong- lots of room
but if you have two cores chances are that one crank is good to go with a good cleaning and maybe polish
do not spend money where you do not have to
Stock rods- save some money and use SPS (same as Mopar performance) rod bolts but do do a quality rebuild- or not with low compression stock pistons and a mild hyd cam
forget studs for the bloc and heads
figure out which gas you are going to run on a daily basis and some here will dial in your compression goal for both cast iron and al heads
do not think about cam too much till you get compression dialed in as cam must match compresion, gears, converter, weight and your right foot and gas mileage goals- (which with a Holly double pumper will be abysmal so forget the eye candy/ bragging rights)
if you do go with the lower than stock pistons keep the cam stock duration but more lift
big cam and low compression is no fun with stock street gears/ converter
if you want a race car build a race car
now after you take the heads off and before removing the pistons measure how far down the bore they are at all four corners with the extension that comes out of your dial calipers and write it down and post it here
you can weigh a stock piston and if close and you use crank and rods as a set you will not have to pay for a balance job
for your application stock 4 bbl manifold and carb will work as well (not quite as light is the only advantage to aluminum dual plane without spending lots of money)
spend your money on first good headers- second good heads (or vice versa) put off cam till you get compression, headers, and heads figured out
The cast iron head exhaust needs a different cam (longer exhaust) and headers (smaller dia)than an aluminum head or the aftermarket "EQ head or the late 308 head))
Virtual build- stick with it
measure twice cut once
do a spreadsheet to track your virtual costs/ benefits
YOU CAN GET ANY COMPRESSION YOU WANT
Track Head CC's on your spread sheet and piston CC's
answer the gas question
Click to expand...
i will be running 93 octane
 
Ottmundr said:
You may want to consider looking at suspension, tires and brakes before go-fast stuff.

Ask anyone who rides a sport bike.

There is a whole section here on suspension and a lot of knowledge available.
Click to expand...
i already have a whole set of new running gear put together on a list which since you brought it up should i do front and rear sway bar or one or the other? and i am gonna bump up my torsion bars as well and a tube k member
 
Tubular k frame seems overkill and very expensive for your performance goals. As stated above don’t worry about cutting the crank. I’m currently putting more hp/torque than you will through a cast cut .010 crank and spining it higher.
 
1969moparDART said:
turnng down the stock crank just makes it weaker
Click to expand...

Where did you ever get an idea like that????? Typical turn down of a crank journal is .010 for clean up; go to a parts store and buy a set of feeler gauges, open them up to the .010 thick leaf, now tell me just how much strength is gonna be lost??? With that kind of reasoning, boring your block over size means you are reducing the strength of your block, so you should never over bore a block; right?? Are your buddies chevy guys????

It's good you are in a non-spending planning stage at the moment, paper is cheep, write down ideas, do some research, with careful thought and action will get you where you want to go
 
Yes, please don't worry over turning down the crank. You will seriously lose maybe 0.01% of strength. You'll break something else first.

The stroker kits run close to $2000 balanced, so that ruins a $3000 budget. One way to beat that price is to go with a cast stroker crank ($350), your stock rods, the pistons I linked in post #8 ($600), and then have the rotating assembly balanced locally (probably $150 for a MINIMAL balance and $300 for a complete balance). But you are still in the $1300-1400 range and you have to bore the block etc. Then there are heads and cam, intake and carb.

So you can see that you'll have to expand the budget well past $3000 to stroke it. If you are stuck on the $3k limit, then something will have to give and the stroker is pretty much out the window.

Do you have a local machine shop? And are you familiar with engine assembly? Not trying to put you on the spot by any means, but having it assembled is a bunch more $$ and that takes a big bite out of your budget. Whether you want to tackle this as your first engine project is a question; it is doable with enough study and info gathering, but is not for those who won'y put the time into studying and asking questions... which you are doing.
 
Your goals of a stout driver are realistic IMHO. You can do good job close to your budget. I would:
  • Keep the stock stroke and crank, and rods
  • Get the compression ratio up with pistons like linked in post 17
  • Get some closed chamber 360 heads like the 308's and just fix them up well (guides, a good valve job), and not buy porting work beyond what you might try yourself
  • Keep the stock rockers and keep lift down to the .460-470"-ish range so the stock rockers won't be over stressed
  • Get a good intake (perhaps a stock cast iron one, or sprig for a better one) and decent 600-650 cfm carb
  • Headers for sure
I think you can stay close to that budget and still do things like a new oil pump, chain set, etc. It'll be a good running 318 with all of that.
 
furrystump said:
Tubular k frame seems overkill and very expensive for your performance goals. As stated above don’t worry about cutting the crank. I’m currently putting more hp/torque than you will through a cast cut .010 crank and spining it higher.
Click to expand...
i know im not gonna have enough power to break anything its the principal though that im talking about, and i know the k member is kinda pricey but i need a new one anyway
 
1969moparDART said:
i know im not gonna have enough power to break anything its the principal though that im talking about, and i know the k member is kinda pricey but i need a new one anyway
Click to expand...
I also comes with a bunch of trade offs. Depending on which one you go with. Whether it uses the torsion bars of coil overs. Just so many other better areas to spend the money which will greatly improve the car. Sure an all out racecar trying to shed every pound sure. Street car? Not so much. Tubular k frame is about clearance and weight loss and changing to rack and pinion steering. It is not stronger than OEM k frame.
 
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furrystump said:
I also comes with a bunch of trade offs. Depending on which one you go with. Whether it uses the torsion bars of coil overs. Just so many other better areas to spend the money which will greatly improve the car. Sure an all out racecar trying to shed every pound sure. Street car? Not so much. Tubular k frame is about clearance and weight loss. It is not stronger than OEM k frame.
Click to expand...
ok well clearence i knew was better with the tubular but i didnt know it was any different strength wise so thanks for that man i guess im staying stock k member
 
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