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View Full Version : 400 HP 318? Can it be done?


1976 Aspen
02-15-2004, 11:31 PM
I have a 1976 Dodge Aspen with a 318 bored .030 over forged pistons, edelbrock performer, Carter 600 manual, heddman headers, stock heads, SSI cam with .442 lift both sides. It's backed up by a four speed with a 8-1/4" 4.10 posi rearend. I'm thinking about doing a cam, intake, and head swap. I'm wondering what I will need to make 400-450 HP at the crank. Which cam? 1.6 roller rockers? Edelbrock heads or port and polish my stock heads with 2.02 1.60? Thin head gaskets for more compression? Any info would be great. I'm not sure what it has now but thinking around 275HP.

1976 Aspen
02-15-2004, 11:36 PM
Here's the car!!!

71SATELITE
02-15-2004, 11:40 PM
Hey man nice rod. One thing you might want to cosider if trying to make the big HP with a teen is stoking it to 4". Lots of stuff available for this. Speedomotive makes a decent kit. It would make a beastly street crusier!!!

74 DART SWINGER
02-16-2004, 12:14 AM
Have you ran it at the strip yet or got any 0-60mph times?:D

sanborn
02-16-2004, 07:02 AM
400HP from a 318 isn't hard at all. It's a matter of what combination do you want.

You need a cylinder head, camshaft combination that will flow about 220-230 CFM at your maximum valve lift. Let me explain; you can get all sorts of cylinder heads that will flow 220 or far more. But, it doesn't do you any good if your valve doesn't open far enough to take advantage of the flow. For the street a camshaft of .500" NET lift is very driveable and give you many choices of cylinder heads. You just need to choose which head you want that flows 220CFM or more at .500" lift.

Your existing carb is OK for 400HP. The intake is probably OK too- although it may need some cleanup and will need a very good port match.

I would mill the heads if you want more compression but keep the Fel Pro gasket. Cometics are better but more pricey. Compression has more affect on Torque than HP.

I don't know about your existing headers, they may be OK but there are some out there that are too restrictive.

Make sure you ignition is in good condition. You've got to fire that mixture in the combustion chamber and many ignitions aren't up to par.

1976 Aspen
02-16-2004, 09:47 AM
So whats the right combo for heads and cam? Edels? Stock port and polish? 360 heads?

rumblefish360
02-16-2004, 12:23 PM
Re-read Sanborns reply. Then have your current heads flowed at a shop. Ask them if getting 220 cfm is possible with your 318 heads with 360 sized valves. (1.88 - 1.60)
If you need the car everyday and taking the heads off is not an option, theres 2 choices here on what you can do.
1. Junk yard 360 heads to work on.
2. MoPar performance sells heads complete. They have ready to go these parts;
1. 360 head assembly P5249459 w 1.88- 1.60 valves. This could use a pocket porting as they list it @ 170 cfm or the 340 head P5249574 @ 200 cfm w/2.02 valves.
2. Magnum head assembly P4876257 that flows 230 cfm.
Thens theres the problem ($$$) of converting everyting else over.
A cam with the advertised duration at/around 280 with a lift of at least .480 is enuff to get that HP level.
1.6 rockers not needed.

jcs98177
02-16-2004, 01:45 PM
Sounds like you have it pretty well complete, so I'm inclined to agree with one of the other replies. Get your self a stroker crank. My choice would be a forged over cast and then it comes down to 4.00 or 4.15 stroke. I stroked my 97 Ram with a 360 which now has 408 cubic inch with w-9 heads. Make sure you use the right pistons so they don't smack the heads and valves. That's costly!

LA360Dart
02-16-2004, 03:59 PM
Hi All;

A few months ago Mopar Muscle ( Mr Dulcich )
did a 318 with Stock Magnum heads and made 400 Hp . This was with a 268XE cam if i remember correctly dual plane intake was used as well. Not very trick really......

Duster_340
02-16-2004, 08:05 PM
Consider using the elcheapo junkyard "302" head used on roller cam 318 engines from 85-91?. Should be cheap and plentiful.
Using these heads will up your compression due to the closed chamber.

rumblefish360
02-16-2004, 08:47 PM
LA360Dart; 909 made us very aware of this in a post because of the use of Magnum heads. An ave. cam of 280* has similar duration as the XE268 I believe. I thought they used a 280* cam in that build up. Are you sure it was a XE268 cam? I just didn't like the use of the MoPar single plane intake on a small displacement engine and also with a cam thats still on the small side.

Duster_340, good point!

jcs98177, they make a 4.15 crank for small blocks? Tell me who! With the 4.00 crank in a teen, piston choices are few if any, but expensive ethier way.

If I had some money to burn, it would be 360 heads with a supercharger from DLI.
(Ahhhh, the love of pipe dreaming. :D )

451Ram
02-16-2004, 08:56 PM
Right now on the news stands is a Mopar Muscle engine review for the year. It has the recipe for 400hp+/318, 500hp+/440, and a scandalous 450hp+/383. It is mopar crazy green on the cover with Steve Dulich on the cover. I think it will stay on newstand until April.

rallye72
02-16-2004, 09:07 PM
I have the article somewhere if I find it i can e-mail it to you, Give me a couple days because I work crazy hours. But hotrod actually did a better job on thier 318 than mopar muscle, the hotrod engine pulled more torque. :chainsaw:

PLUM_72
02-16-2004, 10:32 PM
The 400 horse 318 article was the biggest load of crap i've read in a long time. Unless you port heads for a living and can sonic check for thin spots, there is absolutely no way to perform a port job like that at home. To have a set of heads like that done at a shop, would surpass a set of stage 1 ported eddy heads. Dulcich did his job and sold a lot of magazines on that article. Probably more realistic were his 300 horse 318 articles with the Comp XE262 & XE268 cams. If memory serves the numbers were based on a fresh rebuilt 318.
Dont misconstrue my statement by thinking that 400 horse is an impossible task. Given the right heads, compression and cam it can be done. But your not going to do it in your back yard without spending a wheel barrow full of cash.

1976 Aspen
02-17-2004, 12:04 AM
OK, here's the deal guys. I would like to do this with just a head, cam, and carb swap and as cheap as possible without stroking or even pulling the motor. Any info is fantastic!!!

1976 Aspen
02-17-2004, 11:03 AM
Would heads off a 92 Dodge 1-Ton van with a 360 help my application. Are they the swirl port closed chamber? If not, which heads do I need?

jcs98177
02-17-2004, 03:01 PM
http://www.carcraft.com/howto/116_0401_318/index.html
This tells how they got 400 hp out of a 318. But there is another article with a different build up on a 318 and some where around 400-425 hp. I'll see if one of my friends still has the magazine.

Duster_340
02-17-2004, 09:18 PM
The "360" heads are a good "factory head" starting point for a "340" or "360". The best ones are the casting#4448308 heads. They had an improved exhaust port over the earlier castings.

I would not use the "360" head for your "budget" 318. You will lower your compression ratio and lose power.

I suggest the 1985-1990? 318 "302" head. A "swirl port" head with heart shaped combustion chambers. More compression. Have them mildly ported by a good "Mopar" expert such as W8, who you will find on this board.

Mopar Performance tested a "318" 450 lift cam, 9.0 compression ratio.
The ported "302" head beat the ported "360" head by 30 H.P. on this engine.
A full 55 H.P. gain over the stock heads. Not too Shabby indeed.

The Dartman
02-17-2004, 09:55 PM
400 "real world" horsepower is a tough bid for only "in the car" hopups.

The previous posts are on the right track, though. The heads need to be fully ported and polish to achieve about half of the equation. The other half is a well matched cam, intake, and carberator.

I also think that the 484 lift and 284 duration cam is on the small side as far as your goals.

To compare your request to my 318: My 318 has 12.5:1 Aries pistons that are 40 over. The carb is a 750 mechanical and sits on a Edlebrock Victor 340 intake. The heads are completely unported, unmilled "J" heads with 2.02/1.60 valves, using 273 rocker gear. The cam is a racer brown .510/.292 Hydraulic unit. The mixture is fired by an MSD 6AL.

Roughtly based upon ET, this motor is making approximately 325 HP. This car has some other items that contribute to a fast ET like a 3800 stall, 3.91 gears, ET Streets, and a curb weight of 3065(without the fairly large driver). This car went 12.82@105 on November 1st.

I believe that there is at least a half to full second possibly laying in the P&P of the heads, but time is the biggest factor involved there (or money if I had someone else do it).

Dartman

rallye72
02-18-2004, 02:05 PM
I would love to see some pictures of you car.

jcs98177
02-18-2004, 02:09 PM
Hey man which car do you want to see pictures of?

rallye72
02-18-2004, 04:12 PM
The on in your aviator

The Dartman
02-18-2004, 05:07 PM
Suitable for framing, available in signed and unsigned versions....

Earlier picture:
www.carsandgirls.com/images/73_Duster_Staged.jpg

From my Avatar:
www.carsandgirls.com/petersenracing/images/Speed%20Shop%20Showdown%20Launch.jpg

Best drag car at a car show:
www.carsandgirls.com/petersenracing/images/ScottWins!.jpg

That's about all I have of this car.

Dartman

1976 Aspen
02-19-2004, 12:15 AM
I guess I've heard different opinions on the head part of the deal. I think the head that I wanna use is the magnum cast iron head that Mopar Performance is selling right now for $309 complete with stainless valves and the works. Sounds like the best deal to me. Any opinions on this?

fastmopars .inc
02-19-2004, 04:14 AM
well i think the reason your not pulling the engine is because your trying to keep this down to a minimum amount of work, but seriously, just pulling the 318 and putting in a mildly warmed over 360 would make a world of difference, and would probably be cheaper in the long run. a 360 is gonna make 400 hp a lot easier than the 318, and it will have better street manners as well.

before tossing a bunch of money at such an underdog like the 318, look at the possibility of a swap to the larger cid engine

MoparMarcIdaho
02-19-2004, 06:10 AM
most bang for the buk,BIG BLOCK

Crank
02-19-2004, 10:36 PM
Get the magnum heads you wont be disapointed just open the bowls and polish the chambers ,eddle brock will have a manifold out soon if not now ,call comp cams for advice on a cam use ,a 600 holly cv elec choke or i believe its a 570 street avenger , and that will get you close to what you wont.A 3.91 sure grip , 2800 stall .
(giant killer recipe) just add fuel

motorheadmark00
02-21-2004, 11:20 AM
Hey i got a 76 scamp im rebuilding a 318 the 318 is bored 30 over i got performer dual plane intake and 600 carb summit racing cam hooker comp headers 360 j heads cloyes timing chaing mopar igniton and dyno tune told me around 330hp im not sure will know when i dyno the car over the summer when i switch motors all i wanted to say is that im a young gun to this and untill i bought the 318 i never knew the power a small block could crank out and u guys are my heros cuz u guys can prove u can make some good power out of a 318 wich is believable and every where i went most forums everyone shut me down and said just get a 360 crate motor well not everyone can get 1 and why do that when i can just build a mighty 318 and alot of peaple like to just say run this combo run this combo well we can always diss on eachothers combo but if we all run the same combo were gonna get the same results so i like to keep it open minded so maybe someone will get greater results well in other words for all of you 318 guys out there keep up the good work!cuz im taking notes! MotorHead Mark 16yrs old 76 plymouth Scamp

dwc43
02-21-2004, 12:57 PM
Originally posted by fastmopars .inc
well i think the reason your not pulling the engine is because your trying to keep this down to a minimum amount of work, but seriously, just pulling the 318 and putting in a mildly warmed over 360 would make a world of difference, and would probably be cheaper in the long run. a 360 is gonna make 400 hp a lot easier than the 318, and it will have better street manners as well.

before tossing a bunch of money at such an underdog like the 318, look at the possibility of a swap to the larger cid engine

I would have to agree with you on this one, but the 318 and under dog? It has a lot of potential. We used to run them on some dirt tracks too with great success, if you know how to build them. Used to turn those 6800 at the time and they were pretty quick too. :D

Breech
02-22-2004, 12:51 AM
Well Aspen, I read all of the replies and I have to say that there are some good tips up there. However I have to say that 400 HP out of a 318 is a very tall order regardless of what the magazines say, especially without pulling the motor. I am doing a mild build up on my 318 right now and I'll feel fortunate if I see 250 HP to the flywheel. I'm not saying that it can't be done because it can but you will spend a lot of money and you will have to pull the motor. Even if you could get that kind of HP from simple swaps, I'd be willing to bet that the stock cast internals wouldn't last long and you'd end up having to pull your motor anyways and doing a complete rebuild. If I were you I'd either swap to a larger displacement motor, a 340 or 360 would work well, or I would yank the 318 and do a ground up on it. It might be tougher in the short term but in the long run it would pay for itself and would get you much closer to your horsepower goals. Good luck with whatever you decide to do.

jcs98177
02-22-2004, 07:20 PM
Aspen,

Hey man I would follow what everyone else is telling you here and that is to pull the motor to do the kind of work entailed. I really don't remember what a 1976 Aspen is. Those days were all a blurr. You can build that motor but moving to a 360 will be a world of difference. Trying to work out of an engine compartment is too much trouble. I don't know what magazines you subscribe to but most of them will have a add for software which allows you to build on your PC a virtual motor of your choosing. You start with a block and as you ad things such as pistons, cam, rockers, heads etc it will show power gains or loss. The stock magnum head from 1992-2002 will handle hp 400 and up quite well. They come with 1.6 stamped rocker ( non-roller) but the 1992-2002 block has roller cam and lifters. I went to a 1.7 stamped rocker in my 360 and my valves floated because the springs were not up to the task so I went back to 1.6 roller rockers. I bought a kit with a new cam, lifters, push rods and roller rockers. I gained 19-21 hp just from that alone, but my engine is a 1997 360 MPI. But it was about $500.00. I have been playing with fuel injection just a few years now. I grew up with carbs and this new stuff is different but cool to play around with. Good luck!