318 build up...

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BoredandStroked

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Hey All... here is some fun with crankshafts !

I am building a 318 up and I know its unusual but oh well. I am trying to get between 450 and 500 hp out of it. But I am having a tough time with choices of crankshafts, connecting rods, heads, intake manifolds, and camshafts of course.

For crankshafts I can decided between a 273 forged, 3.578 inch casted, or 4 inch casted. I want rpms but the main thing is power haha. How much would a 3.578 inch (which is a 360 crank) or a 4 inch make my rpms drop? I saw in an article that a group spun up a 318 with a 273 forged crank up to 6500 rpms and made 400 hp. But I am curious at how much a stroker combo will go up too. I know some of you guys have built stroker combos so let me here what you have to say.

For connecting rods I cant decided between keeping my own 318 rods (1973 engine) since I heard they are pretty strong or get a set of repro 340 rods or go with a new set of forged SCAT rods. Any and I mean ANY help with this would be a great help... so confusing since I am trying to learn it all haha.

For cylinder heads I am deciding between Magnum heads and X and J heads (915 casting). Do you have to do any work on the X or J heads to make them work right? I heard you had to do something because it would actually make ur combustion lower if you put them on a 318. The Magnum heads I do not know that much about other than that they are a close chamber design. But I hear they are a great head to use just I dont know much about them.

For intake manifolds you can refer to my other Forum. But I am chosing between the Edelbrock RPM Air Gap, Mopar M-1, Weiand X-CELerator and Stealth. I have NEVER heard anything about the Weiand's so I am curious to see what they can do. I have never heard a bad word on the M-1 side other than the Edelbrock does a better job on the low-mid range end but the M-1 is better for top end. So again... any help in this is greatly wanted haha.

For camshafts... I just need a cam that will work with everything haha... plain and simple. But I dont know where to go for it. So many places like Hughes Engines, CompCams, Crane Cams, Edelbrock, and alot of others.

Ok this pretty much covers everything. I just need alot of help with this engine build haha. As you can tell I am sure but give me a break... I am only 17 and I was a very stupid chevy boy for many years. Finally switched to Mopar and learned what power and knowledge was haha. Thank you all!
 
Oh my lord, what a post. Ask'em in short bursts rather than novels. This is going to take me 1/2 an hour to answer...

I am building a 318 up and I know its unusual but oh well. I am trying to get between 450 and 500 hp out of it. But I am having a tough time with choices of crankshafts, connecting rods, heads, intake manifolds, and camshafts of course.
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No it's not, but doing a stroker on this block is alittle. With this bracket of HP you want, you have unknowingly crossed a line between a inexpensive rebuild to some real cash being spent on a short block and head porting. Yes, at this level, 50 hp in a rebuild is alot to consider. Sure, you can stuff in the biggest cam in the book along with all the other biggest baddest parts and make the number, but you do want it to last more than a few months right... read on.

If your having this much trouble with what parts to use, your in trouble.

For connecting rods I cant decided between keeping my own 318 rods (1973 engine) since I heard they are pretty strong or get a set of repro 340 rods or go with a new set of forged SCAT rods. Any and I mean ANY help with this would be a great help... so confusing since I am trying to learn it all haha.
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Here you are ready to spend money on parts. You c an't decide because you don't know how strong your rods are. This an much more info can be found in a book. Start with the factory offerings and some by Larry Shepard.
Stock rods shot peened and deburred/polished will hold the power. Make'em floaters while there at the machinest. I'd rather go to a good aftermarket unit at the price though. Contact the manufacture for there suggested HP rating and where you should yeild for long term operation.

For cylinder heads I am deciding between Magnum heads and X and J heads (915 casting). Do you have to do any work on the X or J heads to make them work right? I heard you had to do something because it would actually make ur combustion lower if you put them on a 318. The Magnum heads I do not know that much about other than that they are a close chamber design. But I hear they are a great head to use just I dont know much about them.
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The stock head is good till about 430 hp without slamming in a huge cam to make it perform above the expected level. Or trick work. The Magnums are the best bet, but would require some different pushrod lengths and new rockers.
The stock head replacements are a simple bolt on and yes, all would require porting for 500 hp. A set of OOTB Edelbrock heads can yeaild 450 HP without porting. So would some MoPar heads.
The problem is your bore size shrouding the valves hurting power output.


For intake manifolds you can refer to my other Forum. But I am chosing between the Edelbrock RPM Air Gap, Mopar M-1, Weiand X-CELerator and Stealth. I have NEVER heard anything about the Weiand's so I am curious to see what they can do. I have never heard a bad word on the M-1 side other than the Edelbrock does a better job on the low-mid range end but the M-1 is better for top end. So again... any help in this is greatly wanted haha.
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What other forum? All the intakes will make the power you want. The dual planes will make more torque down low and the single plains will make more HP up top.

For camshafts... I just need a cam that will work with everything haha... plain and simple. But I dont know where to go for it. So many places like Hughes Engines, CompCams, Crane Cams, Edelbrock, and alot of others.
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In your case, I'd call a grinder and ask for a recomendation. Any listed can do you well. The problem is, no matter how you ask for there opinion on a cam, it will be a different cam everytime.
If your bold enuff to try our brain power and make the dive into a purchase. Heres a guide line to follow. But beware that theres about 1,000 cams that will fit into these general guide lines.

Chose cam on your cruise RPM range, if you paln on driving anywhere with it.
Limit the amount of lift your looking at. Your heads, what ever they may be, have limits in stock or modified form.
Match the RPM range with the other parts selected. Keep the C-line @ 110.
There, now your down to about 1,000 cams that will fit into the guide lines and probably about 900 that wont work great.

As you can tell I am sure but give me a break... I am only 17
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Sure about what? Yes, I can tell your young with lots-o-questions and a huge curious streak.
Kep asking questions.
IMO, the best bet is to read up in the mags and follow what they did to get the power.
 
Wow... I am like kinda sorry that I typed that much haha. I am actually tired from reading it too haha. Its not really that I am having a problem with the parts to use just I have seen and heard of so many builds that I am confused haha.

So really either crank is a good idea to get a few more horses?

For the connecting rods would the 340 reproduction rods be a good choice or should I just go with Eagle or SCAT. The repo rods would be coming from Hensely Performance.

http://www.hughesengines.com/general/techArticleDetail.asp?articleID=1000024

Check out the above link. Its a set of LA type heads making 588 hp with the whole combo. Thats the reason I am still leaning to them. But I was just told that a set of 302 heads with the swirl port will flow just as well and plus they are made for the 318. The X and J heads are made for 360s and I would have to have them milled down so I wouldnt loose compression. A friend knows a guy that has tons of small block heads so I just gotta choose haha.

The intake forum is some where in the same area as this one so just look around for it.

I know that camshafts are about the biggest thing a person can get robbed on as you said kind of. 1000 cams but 900 are not good at all. What camshaft company is the nicest and most willing to listen in everyones opinion? Haha... cant get anywhere with a person that doesnt want to listen to you.

I meant "As you can tell I am NOT sure but give me a break... I am only 17"

Thanks Rumblefish360 for all of your help !
 
Thanks everybody. Yea, it was a long time doing that one. I teied to keep it on the general side. Lord knows what can happen if you start to show to many things at once.
I myself can't read a single page to long before I read the same dang line over and over.

So really either crank is a good idea to get a few more horses?
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No not really. It's more for torque than HP.
On the rods, how are yours? Upgrading is allways good. But I assumed, (Not allways a good thing) that @ 17 years old, you really don't have a ton of money. (Heck, I don't and I'm 40 LOL)
302 heads work great on 318 because there small skinny ports and valves have great velocity. This works wonder for a small motor. It can work very well on a bigger mill, you just have to use the right part in the right application. So, for an all out drag engine, a stock port and valve sized 302 head would be bad on a stroker 418.
This is also why you'll see over and over that a 360/340 head on a teen is a no-no and not recomended. There is a pay off point, but it's not allways what you may want or end up with likeing.
You'll need things not so great for the street.
Higher than the moon rear gears and converter with ZERO low end. Babys crawling faster than you getting out of the whole. Hyundias whooping your butt in the short run. Etc....

Head runner cc is often matched to the engine size and performance tageted.
Since your stroking a 318 to a larger size, it's not really a 318 anymore now is it?
A 3.58 crank make a 349 or so. Right inbetween the 340/360. So now what head works better.....? (Again, application dependent, but since were on a HI-PO path, yep, 340/360 heads are it.)
( i also really like the Magum head. )

Freindly cam company. Heck, eveybody has there days. It's a crap shot for me who I speak with and how they feel. No ones perfect. Just be freindly and state you need help withere advice for a "Young Gun" (Key word to say to them. It speaks volumes on a lot of fronts.
 
Haha... funny you meantion "Young Gun". After I get this Dart done I am taking it out to the Mopar Nationals to the Young Gun competition. You are totally right about the not having tons of money. I am working all this summer and working 2 jobs my senior school year. I dont know how the rods are yet but hopefully this summer I can get the engine pulled and tear it down and have enough money to do the machine work on it.

Now this is weird but... a friend contacted me and said he knew a guy that had some Magnum, "302", and 340/360 heads. He sells them for pretty cheap from what I gather so... why not buy a set of 302 and 340/360 heads? Port them out and get the 340/360 heads milled down and strap a set of each on and see what works the best. Or am I totally crazy again? How much would it cost to get the 340/360 heads milled down anyways? Ok well I will save you all from my crazy ideas haha. Thank you!
 
Take a breath..you're hyperventilating. Pick set, and do that one set, if you are strapped. You dont have the $$ to do several "just to see". Pick one, and continue the build along that line.
 
IF you are building a 318 to use on the street, use the -302s. i've used them on 318s & 360s and they make great power up to about 5000rpms and loads of torque. if you are going to race only, then use the 360 heads but get a BIG OL stall convertor 'cuz it'll be a slug off the line otherwise.

i've even used ported -675s on my 318s and been happy...snuck a set onto a 360 and it ran just fine for street use.

sb
 
Now this is weird but... a friend contacted me and said he knew a guy that had some Magnum, "302", and 340/360 heads. He sells them for pretty cheap from what I gather so... why not buy a set of 302 and 340/360 heads? Port them out and get the 340/360 heads milled down and strap a set of each on and see what works the best. Or am I totally crazy again? How much would it cost to get the 340/360 heads milled down anyways? Ok well I will save you all from my crazy ideas haha. Thank you!
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Well you listed three heads there. all have pros and cons about them. Magnums, pretty darn good all around head. However, you will need new rockers, pushrods, lifters, valve covers, and a different intake manifold (unless you drill the heads to accept a LA intake). 302s, will bolt on and go. I'd recommend getting 1.88 valves put in, good valve job and maybe a little port work. 340/360 heads have either 1.88 or 2.02s. 2.02s are a little much for a 318, but I actually run them and my car still runs good for being what it is. The cores were given to me from a local mopar member and were setup for 2.02s, so thats what i went with. You will also need to mill down the heads to keep your compression ratio up. If you have the $$, magnums are pretty good heads, then the 302s or 360 heads. Depends on if the 340/360 heads are just smog heads, X's, or J's.....


mopar_nocar said:
IF you are building a 318 to use on the street, use the -302s. i've used them on 318s & 360s and they make great power up to about 5000rpms and loads of torque. if you are going to race only, then use the 360 heads but get a BIG OL stall convertor 'cuz it'll be a slug off the line otherwise.

i've even used ported -675s on my 318s and been happy...snuck a set onto a 360 and it ran just fine for street use.

sb
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Not necessarily...It depends on your whole combo. I run J-heads with 9.7:1 compression ratio. I do have low gears that of course helps for the possible soggy end with my 2.02 valves. With only getting 2,500stall it will still smoke my 275's from a dead stop onto second gear. But i am going to a 3,800rpm flash converter for a little more fun :toothy7:
 
Ok but I am building a 318 stroker that is bored .040 over with a 4 inch crankshaft. Now which would be the best... or does that change anything? Just wondering cause I have the chance to buy a set... just want to make it the right set! Haha... Thank you!
 
BoredandStroked said:
Ok but I am building a 318 stroker that is bored .040 over with a 4 inch crankshaft. Now which would be the best... or does that change anything? Just wondering cause I have the chance to buy a set... just want to make it the right set! Haha... Thank you!
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If your upping for a stroker, i'd say a pair of out of the box edelbrocks. bolt on and go.

If you wanna stick with irons...X's or J's in my opinion. If it were me building a stroker, id go eddies and never look back...
 
Yes I have heard and seen great things with the edelbrocks. I was wondering though... how much should I have the X or J heads milled down... does it all depend on my application or is there a set number when making them fit on a 318 for opitmal everything? What about the edelbrocks? I thought they were made for 340 and 360 so would they have to be milled down? Does everything have to be milled down for a dang 318? hahaha
 
Do you understand why you need to mill heads down? The chamber size effects the compression ratio. What also effects it would be how far the pistons are down in the hole, bore size, and such. If you were to have your block decked (meaning with your little stroker kit in the pistons would come right up flat with the block) and some say 63cc Eddies. You maybe be looking at roughly 9.5:1ish with .030 over pistons. Thats a full guesstimation since every setup is different, but you wont be rediculously low like if you slapped stock X/J's on there which are in the mid 70cc range. To get X's or J's to be milled for 'optimal everything' you need to have your short block put together, and take a few measurements. These motors left the factory with a pretty good variance between piston deck heights and chamber cc sizes. You need to do it for your specific motor and figure out what your compression ratio will be and mill accordingly. My motor, i have 9.7:1 compression with stock replacement .030 pistons, the block was not decked, and 56cc chamber J-heads (factory chamber size is about mid 70's i believe). That works fine for me. But say your stroker kit has different style pistons, you comes higher/shoter up into the bore, etc, etc. Thats on you, the engine builder, to figure out exactly what it needs. We can only do so much, figuring how much things vary from the factory.
 
Yes I know why the heads need to be milled down. The chamber size is to large and drops the compression ratio down. But I understand... do everything while I am building it and dont worry about it until then. Thanks!
 
Get over the haha's already. When in doubt or starting out choose the milder stuff. Smaller heads,cam,carb and intake for sure. To paraphrase BJR the difference will be in the details. Read up on blueprinting. Deck height, ring gaps,bore finish, valve seal, clearances, etc will make as much power as the hot part of the week from the Wizard of Oz braintrust. Use the KISS approach. A 13.0 car is a lot more fun than a 11.0 or 12.0 car that you've afraid to run because something might break and you way overspent on the buildup. I had a batch of people not believe that my B body 318 was not a 440.(back in the mid 80's) Only had 4 non stock parts. Cam(284 purple shaft) gears(5.57) 9inch slicks and a 735 Furd carb(holley). It wasn't scary fast(13.7) but super consistant. Made three runs one night of 13.95,13.95 and 13.96 without shutting off the engine, just pulled back in the staging lanes. It was always fun to watch the Chebby guys race back to the water trough steaming like old faithfull and hearing the yelps when they yanked the upper hose off to stick the cold water into those hot engines. Ran the engine three years and only changed the oil each season.
 
dartjack said:
Get over the haha's already. When in doubt or starting out choose the milder stuff. Smaller heads,cam,carb and intake for sure. To paraphrase BJR the difference will be in the details. Read up on blueprinting. Deck height, ring gaps,bore finish, valve seal, clearances, etc will make as much power as the hot part of the week from the Wizard of Oz braintrust. Use the KISS approach. A 13.0 car is a lot more fun than a 11.0 or 12.0 car that you've afraid to run because something might break and you way overspent on the buildup. I had a batch of people not believe that my B body 318 was not a 440.(back in the mid 80's) Only had 4 non stock parts. Cam(284 purple shaft) gears(5.57) 9inch slicks and a 735 Furd carb(holley). It wasn't scary fast(13.7) but super consistant. Made three runs one night of 13.95,13.95 and 13.96 without shutting off the engine, just pulled back in the staging lanes. It was always fun to watch the Chebby guys race back to the water trough steaming like old faithfull and hearing the yelps when they yanked the upper hose off to stick the cold water into those hot engines. Ran the engine three years and only changed the oil each season.
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Not saying the times aren't good. But slicks and 5.57's will make just about anything fast, but super unpractical for someone that drives on the street more than the drag strip. thats a LOT of gear. 4.30s push the limit for a street/strip car, talking mid 5s? thats screaming.
 
Yes that was a strip only car. It was turning 6700 in the traps. Have seen it up to 7200. My point was that the combination of parts is what makes things happen. Back on task. A notebook and some thought on what the car will be expected to do, cash on hand and careful parts selection is a good start. 500hp from a 318 will be expensive. 400hp would be do-able with some good planning at a reasonable cost. A good starting point for parts combos would be the Mopar Performance/ Direct Connection catalog. They used to have a parts list for several performance levels for each engine size. Mines an early 80's edition so it would be useless now. IMO they did tend to go overboard on valve springs. I think some of the Nextel Cup teams are recycling them on the right front at short tracks. Again,it's in the parts matching and details.
 
dartjack said:
Yes that was a strip only car. It was turning 6700 in the traps. Have seen it up to 7200. My point was that the combination of parts is what makes things happen. Back on task. A notebook and some thought on what the car will be expected to do, cash on hand and careful parts selection is a good start. 500hp from a 318 will be expensive. 400hp would be do-able with some good planning at a reasonable cost. A good starting point for parts combos would be the Mopar Performance/ Direct Connection catalog. They used to have a parts list for several performance levels for each engine size. Mines an early 80's edition so it would be useless now. IMO they did tend to go overboard on valve springs. I think some of the Nextel Cup teams are recycling them on the right front at short tracks. Again,it's in the parts matching and details.
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DartJack, you ought to post more often. Your sensibilities in the quest for the often the unreasonable is quite sobering. I think you'll be hearing from me soon. Between you and Moper I believe I will end up with the most though thru combination to get my car consistently down the track and win.
 
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