How Much HP Can You Get Out a 318

[CoronetRTguy]

So in my quest to get back into the MOPAR world with a car I have this 1973 Roadrunner that keeps haunting me (really it is) to go and look at it and maybe buy.

The car has a 318 in it and I know another member pointed me in the direction of a 318 build from I think Mopar muscle. This member is also doing a build up of a 318 and is looking at a little more HP then Mopar muscle got.

My question is how much HP can a 318 be built to put out?

Also how do I go about building a streetable car and getting a good chunk of HP out of the 318?

I'm sure this motor and trans will need to be rebuilt and with going into it with that in mind I can kind of lay out a game plan. Either way if I do pick this car up or go with my 75 Dodge truck build I'm going to build a 318 or 360.

Do they make turbos for the 318?

I keep thinking of leaving the body stock but I also have the pro-touring bug.

 

[RustyRatRod]

Hang a couple of big turbos on one and I spec you could see 1500 plus.

 

[CoronetRTguy]

Hang a couple of big turbos on one and I spec you could see 1500 plus.

WOW I have been looking at turbo's and kind of just thinking on them. I really dont understand a lot of it but I looked into them when I have my 96 LT4 Corvette.

So a 318 could get that much HP out of it just crazy wow. I was looking at 400-500HP and being happy lol. Who makes the turbo kits for the 318?

 

[67 coronet]

all depends on your pocket book.determine max money for the motor and then you can figure out how much power you can build.

 

[RustyRatRod]

Who makes the turbo kits for the 318?

You'll probably have to fab something up.

Here's a twin turbo 318 in a Charger. 512 HP to the rear tires. He must have a conseravtive setup. That's probably an easy 700 HP plus from the flywheel.

http://www.youtube.com/watch?v=AYBTOGxj88E

 

[Jasoncoronet]

I think you should really think about turbos. First of all you are looking 5,000-10,000 on a motor. The turbos are not cheap nor the motor. To get 400-500 horses out of a 318 is not that difficult. You need good heads, cam and intake. That is very realistic to achieve with a mild bottom end on you motor that wont cost to much. Just my opinion.

 

[RustyRatRod]

The problem you will run into producing much over 600 is that the block will not be able to withstand that much force. It will break.

 

[bigmanjbmopar]

Back in the day we used to get high revving long lasting 318's using 360 heads, of course good valves and stuff etc but was able to go 7-9 grand in an A body @ 140 mph stock bottom end too.

 

[67 coronet]

ya to get real hp out of a smaller engine you either need forced induction or high rev limits.

 

[CoronetRTguy]

Thanks guys good info. I do not know much about motors and all the info you give is of great help.

 

[Cranky]

It's really easy to get 1 hp from each cubic inch......but after that, it get harder and harder. RPM will help and so will forced induction but you need to start studying about air and fuel flow and all that comes with it. You're asking how to make an engine run hard and there's many ways to do that but it depends on how you want to use the engine. For starters, you have a fairly heavy car for a small engine. Small engines hate heavy cars. They don't produce much torque and that's what a heavy car needs. Now if it weighed 2700 lbs, that would be much different but I'm thinking your car is closer to 3700.....

 

[nothingbutdarts]

If you put the same amount of money into building a 318 that you would put into a 360, you would have more horsepower and torque in the 360 anyday! 360's are really cheep to buy and plentifull.

Just keep the 318 tucked away if you need it for originality.

 

[jessipup]

Here is a different angle. Instead of chasing a big HP number, chase a big torque number.
High HP is usually found at the top of the rev range and you'll be going plenty fast already by the time you get there.
If you chase torque and especally in the first half to 3/4 of the rev range. You will have much more fun. Torque is that thing that will push you back in the seat and set those tires a smokin

 

[dvw]

View attachment 97548View attachment 97549I did a 318 many years ago for my sons friends Dart. 484 purple cam,stock 360 heads,stock TQ & intake,headers,2 1/2" exhaust,stock trans, stock converter. O.E. used short block in decent shape. 4.10 gear it would run 14.0@101. Now the turbo 360 idea. Sons 62 Savoy, 360,forged pistons,reground factory hyd roller(.490" lift),new rod bolts, a little head work,truck manifolds with 1 7/8" outlet,prehistoric single plane swap meet intake,nice E-85 850 carb,76 mm turbo,PTC converter,2.76 8 3/4,255/60 drag radials. 10.99@123 at only 8 psi, plenty left
Doug

 

[tallhair]

I did a 318 many years ago for my sons friends Dart. 484 purple cam,stock 360 heads,stock TQ & intake,headers,2 1/2" exhaust,stock trans, stock converter. O.E. used short block in decent shape. 4.10 gear it would run 14.0@101. Now the turbo 360 idea. Sons 62 Savoy, 360,forged pistons,reground factory hyd roller(.490" lift),new rod bolts, a little head work,truck manifolds with 1 7/8" outlet,prehistoric single plane swap meet intake,nice E-85 850 carb,76 mm turbo,PTC converter,2.76 8 3/4,255/60 drag radials. 10.99@123 at only 8 psi, plenty left
Doug

that is a serious sleeper dvw

- - - Updated - - -

If you put the same amount of money into building a 318 that you would put into a 360, you would have more horsepower and torque in the 360 anyday! 360's are really cheep to buy and plentifull.

Just keep the 318 tucked away if you need it for originality.

this seems to be a reasonable course, switching to a 360 will net you more torque and horsepower and more upside over the 318 and as nothingbutdarts says you can just put away. also for the cost of the 360 you'll be way ahead in the torque dept of the 318 already w/o any serious work.

 

[YY1]

I LOVE that 62!!

 

[HT413]

I did a 318 many years ago for my sons friends Dart. 484 purple cam,stock 360 heads,stock TQ & intake,headers,2 1/2" exhaust,stock trans, stock converter. O.E. used short block in decent shape. 4.10 gear it would run 14.0@101. Now the turbo 360 idea. Sons 62 Savoy, 360,forged pistons,reground factory hyd roller(.490" lift),new rod bolts, a little head work,truck manifolds with 1 7/8" outlet,prehistoric single plane swap meet intake,nice E-85 850 carb,76 mm turbo,PTC converter,2.76 8 3/4,255/60 drag radials. 10.99@123 at only 8 psi, plenty left
Doug

10 second car running 2.76's. that's just not fair.:icon_thumright:

 

[RustyRatRod]

That's how to make that turbo work. Give it some resistance. lol

 

[66 coronet deluxe]

I had a 318 in my coronet when I bought it. Was stock rebuild with 4 bbl intake, headers and 650 holley. Car went like stink with that 318 in it, had the 120 mph speedo buried many times. Those motors really rev when built up a bit. I would buy the car and drive the crap out of that 318 till it dies. In the mean time you could buy a 360 and build it up, the 360 would give you the extra torque it takes to move that B body quicker.

 

[CoronetRTguy]

I had a 318 in my coronet when I bought it. Was stock rebuild with 4 bbl intake, headers and 650 holley. Car went like stink with that 318 in it, had the 120 mph speedo buried many times. Those motors really rev when built up a bit. I would buy the car and drive the crap out of that 318 till it dies. In the mean time you could buy a 360 and build it up, the 360 would give you the extra torque it takes to move that B body quicker.

Right now the car doesnt run and I'm not sure what it needs to make it run. I will look into the 360s around here.