How much HP with a 318?

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73VAswngr

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I've got a good line this time on a new in crate 318 short block for $250. What kind of horsepower can you get out of a 318 with aftermarket heads? What would you do with a 318 short block? I need all the pointers I can get. Thanks.
Russ
:read2:
 
with a better choice of pistons, stock edelbrock heads and a bigger cam. i'd go well into 12s with a 3600lb car with a 318.
 
I would look for 308, 360 heads and keep the smaller 1.88 valves, use a dual plane intake w/a 650 carb, cam in the rpm range I'm looking to make power in and headers w/2-1/2 piped exhaust.
 
350 HP is very do-able with better heads and keeping it in a modest price range. Above that you can spent 4k easy. So above that it is better to start with a 360 for thee $$. But there are a lot of 318's that make over 500HP with enough $$ and love!
 
You will want to go with some closed chamber heads to get the compression up. I'd measure how far down in the hole those pistons are sitting. If they are real far down there go with a thin head gasket too.
 
rumblefish why stick with188 valves instead of hawging to 202?? im setting my 318 up as per mag article 360 heads cut for 202 "ported" block punched 060 with hyperk pistons wit stock(NOT WHAT IM USING) 360 castiron intak and castiron ex eng made 357 HP and 388 ftlbs torque we are going to go a few step further to make around 400ftlbs tq and 365-375HP that combine with MY ^%dartGT 833 w/355s should run out fairly quick oh an with all parts an machine work still cheaper than a crate eng
 
Hers my combo.

318 .030 over kb167 pistons,eagle sir rods, reground crank,lunati .455 voodoo and magnum heads. Comp is about 10.25:1.

Looking for lots of torque for a heavy car.Des top dyno says well over 370 ft/lb's from 2000 to 3500 rpm. Very flat tq curve! And about 320 h.p
 
But there are a lot of 318's that make over 500HP with enough $$ and love!
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You mean lots and lots of money,and how long do they stay together??...
 
I have 318 30 over, kb399, 360 heads milled .035 ported 1.88/1.60, Edel air gap, erson 488/510, 650 dp holley. Its in a dart that weighs 3350 w/me and I run 12.90's. Did a little more tuning and hoping for 12.80's this year.
 
65DrtGT said:
rumblefish why stick with188 valves instead of hawging to 202?? im setting my 318 up as per mag article 360 heads cut for 202 "ported" block punched 060 with hyperk pistons wit stock(NOT WHAT IM USING) 360 castiron intak and castiron ex eng made 357 HP and 388 ftlbs torque we are going to go a few step further to make around 400ftlbs tq and 365-375HP that combine with MY ^%dartGT 833 w/355s should run out fairly quick oh an with all parts an machine work still cheaper than a crate eng
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Thats the exact mag article i built my motor from ...tho it said it used a 750 CFM carb ...after lackluster performace i swapped in a 600 and its a little better ...how are you doing with that motor and whats your timing set at ....for the love of god i cant get it right, Thanks
 
needsaresto said:
Hers my combo.

318 .030 over kb167 pistons,eagle sir rods, reground crank,lunati .455 voodoo and magnum heads. Comp is about 10.25:1.

Looking for lots of torque for a heavy car.Des top dyno says well over 370 ft/lb's from 2000 to 3500 rpm. Very flat tq curve! And about 320 h.p
Click to expand...

Wow,that's almost identical to my build, except I am using 68cc 360 heads and my block is .040 over, will give a better heads up of HP/Torque when I get it together and on a dyno
 
65DrtGT said:
rumblefish why stick with188 valves instead of hawging to 202?? im setting my 318 up as per mag article 360 heads cut for 202 "ported" block punched 060 with hyperk pistons wit stock(NOT WHAT IM USING) 360 castiron intak and castiron ex eng made 357 HP and 388 ftlbs torque we are going to go a few step further to make around 400ftlbs tq and 365-375HP that combine with MY ^%dartGT 833 w/355s should run out fairly quick oh an with all parts an machine work still cheaper than a crate eng
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Sorry about the delay in responding.

The small engine can use all the velocity is can get with the small cam. The larger open chambered heads reduce compresion and will require more timing to run best. The larger ports will have less velocity to atomize the air and fuel charge. This means bigger droplets of fuel in the cylinder. These bigger droplets are harder to fully ignite and burn. A full burn of the air and fuel is what everyone is looking for or your just wasteing the gas.

Ported, the 318 head can still out perform a 340/360 head ported or not. It will still have a higher velocity than the bigger port heads.

Remember, the dyno may say big power, but how it acts in the car is a different story. I'm generally not a fan of anything bigger than a 650 on a 318 when it see's the street. A track 318 is another story. I don't care how much anybody screams about the bore size of the carb and how what acts like what. IF your driving the street, and it's not a crusher of a teen, you want the 318 heads and not larger than a 650 on it.

360 heads on a teen are OK and can be cheaper than porting 318 heads. You'll give up torque down low, but then again, you or the engine may not care. Things like a bigger cam, higher stall converter and gears aren't even operating in the lose area.
 
needsaresto said:
Hers my combo.

318 .030 over kb167 pistons,eagle sir rods, reground crank,lunati .455 voodoo and magnum heads. Comp is about 10.25:1.

Looking for lots of torque for a heavy car.Des top dyno says well over 370 ft/lb's from 2000 to 3500 rpm. Very flat tq curve! And about 320 h.p
Click to expand...

What intake are you using? I think you are judging quit low at 320hp. You should be closer to the 400 mark with that build. JMO
 
rumblefish360 said:
Sorry about the delay in responding.

The small engine can use all the velocity is can get with the small cam. The larger open chambered heads reduce compresion and will require more timing to run best. The larger ports will have less velocity to atomize the air and fuel charge. This means bigger droplets of fuel in the cylinder. These bigger droplets are harder to fully ignite and burn. A full burn of the air and fuel is what everyone is looking for or your just wasteing the gas.

Ported, the 318 head can still out perform a 340/360 head ported or not. It will still have a higher velocity than the bigger port heads.

Remember, the dyno may say big power, but how it acts in the car is a different story. I'm generally not a fan of anything bigger than a 650 on a 318 when it see's the street. A track 318 is another story. I don't care how much anybody screams about the bore size of the carb and how what acts like what. IF your driving the street, and it's not a crusher of a teen, you want the 318 heads and not larger than a 650 on it.

360 heads on a teen are OK and can be cheaper than porting 318 heads. You'll give up torque down low, but then again, you or the engine may not care. Things like a bigger cam, higher stall converter and gears aren't even operating in the lose area.
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I agree with Rumble. If i were to use a 360 heads i would make sure they were 596's. These have the 1.88 valves and would keep the velocity up. The Mags would even be better. Its my understanding that they are the Best head for a 318, period
 
sublimeswinger said:
What intake are you using? I think you are judging quit low at 320hp. You should be closer to the 400 mark with that build. JMO
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400HP REALLY?? That's almost the exact same build I am doing but I didn't put it anywhere near 400HP I was thinking closer to ~320HP as well, but 400HP would be outstanding if that's what it puts out when it finally gets together.
 
Well my .030 over 318 has those high swirl heads, not the 308's but what MP cast right afterwards for the aftermarket. Its based on the 308's but has no air port holes and came with 2.02 intake valves.

It rocks :cheers:

All I did was let Muscle Motors here in Michigan milled them .030 and they redid the valve job and "hog something" the bowls ?? Not sure-I didn't ask them to but guess they thought it be good to do. Heads CC at 63.

Now it does have 3.91 gears and a hot MSD 7al spark box with the HVC coil-really helps out to burn that gasoline-I am a firm believer in having a good hot spark. I have put my old MSD 6 box back on and it does slow down and needs leaner jets--would have got that MSD 8 box but the $1,000 price stop me-but the tech line told me it last "forever" on the street with the right coil.

Got a Demon race 650 carb and it pulled better than a 950 I tried-very top end the 950 edge out but the mid range is better with the 650 and with gas prices soooo high, a 1/2 MPG matters.

Never tried the 1.8 intake valves but I can't see it helping but sure, if the car had 3.21's, even 3.55 gears and a weaker spark, I could see the 360 heads not being the best but for my combo--it ROCKS. :happy10:

Have a custom cam ground by Mike Jones in NC-only is a 220 @ .050 but it pulls to 6200 rpms. Not a whole lot of lift @ .465 but we felt the cam will last longer on the street since I tend to rack up the mileage. He does have "racing cams" with faster lift rates but I don't tear the motor apart and replace parts every season--at least not yet, lol.
 
Remember, a .030 318 is 323 CI, thats only 17 CI less than a 340.

GM had their 302's and 327 motors with big ports and 2.02 intake valves. Ford had their Boss 302 with a little larger than 2.02 intake valves.

It can and does work, if the combo is right. Back in 1970, 4.10 gears on the street were the min. Some were running 4.56 gears and were having 7500 rpms red lines. But they were running 12-1 compression and burning high octane leaded gasoline.
 
still dont have my car :( Hopefully tomorrow... does a 727 work with a 318 or do you need the 904?
 
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