Looking for a little more power out of a 318

-
Is there a reason for that particular hp level? Most builds need a result to plan for. I use a performance window, because power output is a part of the equasion, not the entire equasion. Do you run power brakes? Do you race the car? Plans to race the car? How much money do you have for the powertrain part? IMO, you need to define the scope, before you can zoom in on the bulls-eye. There's a bunch of ways to get more power, or get the car to run faster for what you do with it.
 
http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/index.html

Heres a good article for 400+

I like the teen myself. You have a fresh rebuild, and to me thats the problem, who did the rebuild? stock rebuild with something other then a stock cam seems a little fishy to me. I think you stated that you dont know the specs of the cam. I think thats a problem, without knowing that its hard to figure out what "add ons" you should do.
Is the motor in the car and running? If its not in the car, do what you want to it. my suggestions would be

Comp xe 262-268. To be honest you wont tell the difference and the 262 will hold a little more torque

Intake- This is where you need to decide how much money you want to put in and how far you want to go.
little money- Eddy preformer
more money-Airgap........but, with the air gap you need to upgrade other things, like heads and carb. so make the dicision first. Heres my favorite build

318- bored .30
KB167 pistons
596 heads, the smaller 1.88 valves, not 2.02 you still need the velocity
Air gap
600-750 carb
XE262 or 268 cam with 901 springs
mopar thin head gasket. This brings you to zero deck without haveing the deck squared.
Eagle I beam rods
 
little money- Eddy preformer
more money-Airgap........but, with the air gap you need to upgrade other things, like heads and carb.
Click to expand...

Just to clarify for Cole;

The RPM and Air-Gap RPM will perform the same except in warm up times in cold weather driving. There port sizes are 340/360 sized. This is where the extra money in upgrades are. Purchase 340/360 heads or port out the 318 heads.
Otherwise, your good.
 
Thanks for the tips. But yes, sadly I do not know what the cam specs are. The motor is in the car and I've been driving it daily. The car idles rough for about 10 minutes, then its fine. I have to put it in neutral once in awhile at stop lights. I just took it to the track this weekend, and was disappointed in my time slips. The 318 is alright for a daily driver, but I've decided to go with a 360. I already know some basics of what I'd need, but I'm going to start a new thread to get opinions. Thanks again.
 
If you have the 73-76 spool type motor mounts have you guys ever checked with your dealer? I got a replacement pair for my 340 and it was no trouble at all. I believe Schumaker has replacement, not conversion, mounts with urethane instead of rubber for the late style mounts.
Read this....
http://www.popularhotrodding.com/enginemasters/articles/mopar/0667em_mopar_318_engine/index.html
Or this
http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/index.html
And this
http://www.moparmusclemagazine.com/techarticles/155_0312_318_long_block_bolt_ons/index.html
And this...http://www.hotrodders.com/forum/318-mopar-build-up-24359.html
Ya gotta love Google...typed in 318 and found all this in seconds!
Hope it helps!
Alan
 
ColeTrickle74 said:
Thanks for the tips. But yes, sadly I do not know what the cam specs are. The motor is in the car and I've been driving it daily. The car idles rough for about 10 minutes, then its fine. I have to put it in neutral once in awhile at stop lights. I just took it to the track this weekend, and was disappointed in my time slips. The 318 is alright for a daily driver, but I've decided to go with a 360. I already know some basics of what I'd need, but I'm going to start a new thread to get opinions. Thanks again.
Click to expand...



What did it run?
 
Ran low 17's high 16s all night. Made about 6-7 passes. 1/4 MPH was 74-79. I finished in 2nd gear a few times. Must have a 2.XX gear.
 
I have run low 15's on a worn out almost completely stock 318 with 2.94 gears and I was maybe pushing 240 hp?? It is possible to make some power out of the teen and go fast.

If you really want a 360 instead, go for it. It will just make us fast 318 guys that much more rare ;)

My 318 was most definately worn out, and the crank was shot, but now it is torn down in my garage, with a small list of decent parts including stock forged 273 crank, 302 heads, and xe268. I have the base now I just have to wait for some cash flow for the machine work and all the other little goodies that make it work.

Good luck on your project though.
 
Dartboy52 said:
I have run low 15's on a worn out almost completely stock 318 with 2.94 gears and I was maybe pushing 240 hp?? It is possible to make some power out of the teen and go fast.

If you really want a 360 instead, go for it. It will just make us fast 318 guys that much more rare ;)

My 318 was most definately worn out, and the crank was shot, but now it is torn down in my garage, with a small list of decent parts including stock forged 273 crank, 302 heads, and xe268. I have the base now I just have to wait for some cash flow for the machine work and all the other little goodies that make it work.

Good luck on your project though.
Click to expand...

Add some KB's to that while your at it. Do you already have the 302's? If not i would re think those.
 
Check out the Oct. 2008 issue of Popular Hot Rodding magazine, they built a 400+ HP 318 on a budget. Good build with good results.
 
sublimeswinger said:
Add some KB's to that while your at it. Do you already have the 302's? If not i would re think those.
Click to expand...


Why do you say rethink the 302s? They are a good head to use for the 318 IMO. If I was building a stroker or something with larger displacement I would go another route, but it is still going to be a 318 with whatever cylinder wall clean up I need.

I had the stock 302 heads on the car for a little bit before I tore it down just to see how they felt and they felt pretty damn strong, lots of low end. I plan to put bigger valves in them and have them mildly ported. Along with more compression; decent pistons and 0 deck, I am looking for 375-400HP at the engine, which I think is very possible.

ocdart, thanks for the recommendation, I know there have been some other good 318 builds, one by MM a while back and another by Hot Rod, and maybe a third. They are all good reads and I will have to check this new one out.
 
I am in the process of finalizing our build on the little teen for the Duster and according to the Comp Cam Camquest program we should be about 365 hp and 394 tq. That is a far cry from the sad 150/170 hp stock..

She will be .030 bored with gasket matched/pocket ported 302 casting heads with stock size valves, Comp 268H cam, springs etc, an Edelbrock RPM Air Gap with a Holley 670 Street Avenger.

I had the heads cc'ed the other day and they were 59cc's. When we square deck the block it is very likely that the KB167 pistons would make the compression at 11 to 1 or a little more maybe. We decided (with great advise from BJR) to go with the '85-'90 pistons which have about a .025 compression height increase over the stock pistons. We will deck the block for 10 to 1.

With a little more cam 375hp would be attainable but I got a great deal on all these parts including the cam kit. The torque numbers for this little motor look pretty good with that cam though.

Good luck Coletrickle74. I too have heard the 302 casting heads are the ticket for a medium 318/322 build.
 
he meant, if you dont have them you should re think that and possibly get some

Dartboy52 said:
Why do you say rethink the 302s? They are a good head to use for the 318 IMO. If I was building a stroker or something with larger displacement I would go another route, but it is still going to be a 318 with whatever cylinder wall clean up I need.

I had the stock 302 heads on the car for a little bit before I tore it down just to see how they felt and they felt pretty damn strong, lots of low end. I plan to put bigger valves in them and have them mildly ported. Along with more compression; decent pistons and 0 deck, I am looking for 375-400HP at the engine, which I think is very possible.

ocdart, thanks for the recommendation, I know there have been some other good 318 builds, one by MM a while back and another by Hot Rod, and maybe a third. They are all good reads and I will have to check this new one out.
Click to expand...
 
74Burntorange said:
he meant, if you dont have them you should re think that and possibly get some
Click to expand...


Actually, thats not what i ment, lol i ment if you dont have them, there are better heads to chose from. The 302's need alot of work to flow as well as other heads with less work. A little "clean up" on a set of 302's is a waste of money IMO, unless you do it your self, and still then, it would be hard to get equal numbers out of these heads.
A better choice would be a 360 headd with a 1.88 vale to keep the velocity up. But the ultimite choice would be a set of magnums.
 
sublimeswinger said:
Actually, thats not what i ment, lol i ment if you dont have them, there are better heads to chose from. The 302's need alot of work to flow as well as other heads with less work. A little "clean up" on a set of 302's is a waste of money IMO, unless you do it your self, and still then, it would be hard to get equal numbers out of these heads.
A better choice would be a 360 headd with a 1.88 vale to keep the velocity up. But the ultimite choice would be a set of magnums.
Click to expand...


I would think the bigger chambers of the 360 heads would hurt compression with a stock piston.
I myself will be working a set of 302's this winter I will only enlargen the exhaust valve to 1.60 and then gasket match.
 
I have a 318 as well I'm not sure what cam we went with but we bowl hogged a pair of 360 heads for quench {which really dropped the compression }and went with a stealth intake eidle600 and a set of tti headers into the tti 2.5 inch exhaust and she burns the 265 60s off with a 323 rear gear and a 727tf , we went with the auburn for the 323 cause I want to drive her cross country several times a year and that was the smallest number I could get for my 8.75 . we went this way with the motor so that if and when { more when eh!haha } the bottom go's on the 318 we can just pick up a new stroked 360 shorty cheap { rotating assemblies are going for nothing right now} and swap it right in with all the extras ready to bolt right over { I'll probably rebuild the 318 bottom and put the old 2bbl set-up back together with the old 904 and save it just cause it's #s matching} without having to re-spend on heads intake etc... why throw out a strong motor when you can wear it out eh? get some old tires and go burn her out if your so set on changing haha:burnout:
 
If you're planning a 360 for later, I'd run the 318 until you can put it in. To get the kind of power you're looking for from the 318, you're looking at laying out quite a few dollars. IMO the outlay doesn't make sense if you're going to swap engines ASAP.

I'm going to agree with Rumblefish that according to the formula, a 318 @ 85% volumetric efficiency can get by with a 500 cfm carb. Personally, I went with a bigger carb because that's what Mopar stuck on the HP 273 running less cam than I am.

You'll need a different driver's side engine mount for the 360. Also, if you use an aluminum intake, you'll need a fiber intake gasket set.

My Demon engine is a 318 with 302 heads. I'm very pleased with it as a "driver". Pistons are made to the specs of the early LA 318 when it had a 9.2:1 compression ratio. With the 302 heads, I believe it bumps it up a little more. I have a .441 lift cam 218/228 @ .050 lift. The intake is an Eddy Performer (small ports to match head) topped off by a 625 cfm AFB. It also has a double roller timing chain. I'm using a 360 A-body exhaust manifold on the driver's side and a Magnum V-8 one on the passenger side. Other than that, the motor is pure stock with no machining. The combination runs well on mid-grade gas and throttle response is quite good with 3.23 gears. I'm going to estimate around 275 hp.
 
sublimeswinger said:
Actually, thats not what i ment, lol i ment if you dont have them, there are better heads to chose from. The 302's need alot of work to flow as well as other heads with less work. A little "clean up" on a set of 302's is a waste of money IMO, unless you do it your self, and still then, it would be hard to get equal numbers out of these heads.
A better choice would be a 360 headd with a 1.88 vale to keep the velocity up. But the ultimite choice would be a set of magnums.
Click to expand...

Your not looking for equal numbers out of the 318 head to compete with the 360 head, the issue is velocity in the port and you have to keep in mind the the short stroke and bore size of the 318 will work with great and efficent vs a 360 head.

It's an issue of the size of the bore and stroke combo and the volume of the port. Of course how well the port flows is an issue, but if the port is large and flows the number sought it will be dogish and get it's *** whooopped by a smaller head and valve combo with a port constantly moving aair at a high rate rather than waiting until you can use the larger head.

The small port head cleaned up and port matched is a better head for a mild 318 than a 1.88 360 head box stock. A 1.60 valve for exhaust on the teen head is a good idea.
It could work out cheaper - easy - than a purchase of a 360 head.
 
i have had great Success with a 318 that i built several years ago it was in a 3/4 P/U it was .030 over 318 with a 505/292 Cam from Isky 244 @ .50 i advanced the cam 4 Degrees Ported a set of 340 J-Heads With 2.02/1.60 3000 stall converter 410 rearend gears 33" tall tires 700DP Holley Carb Headman Headers 2 1/2" Exaust Edly Torquer 2 intake this Como ran 12.90 @ 113 Mph At Carlsbad raceway in Carlsbad Ca. it was a great work truck that i could do anything i wanted to most of the parts i have Sugested you can still use on your 360 Motor. i also got 14 MPG
if you want to know more you can Contact me

At [email protected]

have a great day
 
ok i have 73 318 auto 355 dyna max ceramic headers ebrock performer intake and 600 cfm carb what mild cam can i put into wake up a little would not mind a n little lope but would rather not have to change convetor thanks be safe
 
A cam with a little lope is ground on a tighter centerline like a 110 or 108. Further down numericaly, the more chop to the cam. I have a Crane in mine on a 112. A slight chop to it and when fully warm, nearly gone. (That was the main idea)

I'd look at a split duration cam like around 224 intake degrees of duration. Look up a Comp XE series cam.
 
I have a comp XE 284, thing has a mean lope in a 318, I can tell you.... but rumblefish has some good advice. Comp XE262 or XE268 would be really good choices for you. 262 if you want good power with really good street ability, 268 if you want to trade a little streetability for some top end power and and little more rough idle.
 
You must log in or register to reply here.
-

Back
Top