Big horsepower 318 builds

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Probably not that high. Maybe 6500 and that’s barely above an idle in 2024.
I was estimating based off this 323 that makes 477 hp @ 6500 rpms and 427 tq @ 4,900 rpms, making with a decent 1.32 lbs-ft per cid and 90% of of peak torque at peak power.

He just needs to find 18 lbs-ft @ 6,500 rpms to hit 500 hp (404 lbs-ft) from the 477 hp (386 lbs-ft).

https://www.motortrend.com/articles/0901phr-mopar-318-magnum-engine/

RPMTQHP
2,500337161
2,600350173
2,700357183
2,800357190
2,900356196
3,000351201
3,100345204
3,200339207
3,300343216
3,400356230
3,500371247
3,600385264
3,700396279
3,800404292
3,900410305
4,000415316
4,100418327
4,200420336
4,300422345
4,400421353
4,500420360
4,600421369
4,700425380
4,800426390
4,900427398
5,000427407
5,100427414
5,200426421
5,300425428
5,400423435
5,500421440
5,600419446
5,700417453
5,800415458
5,900412462
6,000407465
6,100401466
6,200397469
6,300393471
6,400390475
6,500386477
 
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I was estimating based off this 323 that makes 477 hp @ 6500 roms and 427 tq @ 4,900 rpms, making with a decent 1.32 lbs-ft per cid and 90% of of peak torque at peak power.

He just needs to find 18 lbs-ft @ 6,500 rpms to hit 500 hp (404 lbs-ft) from the 477 hp (386 lbs-ft).

https://www.motortrend.com/articles/0901phr-mopar-318-magnum-engine/

RPMTQHP
2,500337161
2,600350173
2,700357183
2,800357190
2,900356196
3,000351201
3,100345204
3,200339207
3,300343216
3,400356230
3,500371247
3,600385264
3,700396279
3,800404292
3,900410305
4,000415316
4,100418327
4,200420336
4,300422345
4,400421353
4,500420360
4,600421369
4,700425380
4,800426390
4,900427398
5,000427407
5,100427414
5,200426421
5,300425428
5,400423435
5,500421440
5,600419446
5,700417453
5,800415458
5,900412462
6,000407465
6,100401466
6,200397469
6,300393471
6,400390475
6,500386477


It’s a point low on compression for a decent pump gas build.

If it was 11.5:1 it would increase power without increasing RPM.
 
I figured the trick flow springs would do better than that.. but i didn't buy the top end kit.. got the hyd. roller ones
You left that info out of the comment I replied to.
 
LOL. My bad.
RRR, have a serious question though... i'm a ******* idiot and do everything wrong and looking at my receipt for my heads i bought the TF's with the flat tappet springs, i know it just comes down to rate and such and i think they are fine. If i did my math right way back my OTN pressure is 305#,
Cam is small .525/.532 but howards doesn't list a spring rate/pressure (might be on the cam card at home)

This is the spring spec that i got, their hyd roller spring they list is about 20lb difference across the board.. i think i'm just making myself worry over nothing though..

Standard: 1.460” O.D. Dual Spring (TFS-16893-16)
120 lbs. @ 1.900” Installed Height
394 lbs. @ 1.175” Open
390 lbs./inch Rate
.650” Maximum Valve Lift
 
It’s a point low on compression for a decent pump gas build.

If it was 11.5:1 it would increase power without increasing RPM.
Per the contest rules for that years enginemasters competition, the engine was scored from 2500 to 6500, and the compression had to be under 10.5 to 1, hence how it was built.
BTW.. the 248/248 cam used in the competition wasn’t the one I used in the car.
I had a much smaller 230/236 in it. Was worried about those beehives living in a real world street/ strip environment. That 248 cam was pretty nasty…lol
Little sucker revved like a gas weed whacker
 
Per the contest rules for that years enginemasters competition, the engine was scored from 2500 to 6500, and the compression had to be under 10.5 to 1, hence how it was built.
BTW.. the 248/248 cam used in the competition wasn’t the one I used in the car.
I had a much smaller 230/236 in it. Was worried about those beehives living in a real world street/ strip environment. That 248 cam was pretty nasty…lol

I saw the rules. I was meaning I wouldn’t build it that low on pump gas. Unless the rules made me.
 
I had a question bout that also, if beehives are great, and supposed to help oscillation and all that why do companies still use normal straight dual springs?
 
Per the contest rules for that years enginemasters competition, the engine was scored from 2500 to 6500, and the compression had to be under 10.5 to 1, hence how it was built.
BTW.. the 248/248 cam used in the competition wasn’t the one I used in the car.
I had a much smaller 230/236 in it. Was worried about those beehives living in a real world street/ strip environment. That 248 cam was pretty nasty…lol
Little sucker revved like a gas weed whacker
How was the streetability ?
 
K.. since we are discussing and not arguing for once bout 318s... my 318 is a bone stock '85 bottom end... keep under 6k and treat it nice? just curious where the worry point should start...

IMO, worry point is how hard it’s used and how often.
If it’s a RPM worry, I’d say anything past 6500 unless you know how big the oil passages are & couple that with oil PSI.
10 PSI per thousand RPM is very good to have and shouldn’t be a problem.

If the oiling passages are smaller than the books recommended size, this could be an issue above 6500. Spinning past 7K, I’d recommend going above and beyond the recommended modifications and address every passage in the block making it slightly larger, rounding corners instead of the 90* turns, bushing lifter bores, etc.
 
I saw the rules. I was meaning I wouldn’t build it that low on pump gas. Unless the rules made me.

BTW.. it was in this I used to own, I bought it as a roller, painted steel bumpers, full bench seat interior, column shifter

IMG_0019.jpeg
 
I had a question bout that also, if beehives are great, and supposed to help oscillation and all that why do companies still use normal straight dual springs?
Could be cheaper to produce and if it still does the job needed, they are just happy with that and will say, Just send it, your good to go.”
 
How was the streetability ?

Drove like a Taurus, drove it to the track and back several times, tame idle. Did have a 4500 ish vert in it with 4.10’s
Guy I sold it too, his wife putts around in it, they are local to me.
They put full exhaust on it out to the tips.
It’s an ultra sleeper
 
Tell you guys what…. Anybody who ever gets or has a set of the iron magnum RT heads, they are sweet pieces.
I have zero doubt it would be rather easy to run 10’s with them on top of a roller cammed stock stroke 318 with some squeeze( compression)
3000 pound typical bracket car would do it very easily, without working up a sweat.
 
Not sure if you remember Uncle Tony showcased this in a video saying the timing chain broke...his nut swingers ate it up...
First, I know UTG has been wrong on a few topics, but it's usually minor or is corrected sometimes. I don't agree with everything he says, so most of it is entertainment to me.

Second, He never said the timing chain broke.

Third, he said that he could be wrong and it's just his assumption of what may have happened, which was the timing chain being too tight that could effect things.

Fourth, whether it's intended or accidental you are putting words in someones mouth when you rely on your misunderstood memory. Even I need to fact check myself sometime so I don't make false or misinformed claims. And remember, there are other content creators here, you could accidentally make false claims about them too.
 
First, I know UTG has been wrong on a few topics, but it's usually minor or is corrected sometimes. I don't agree with everything he says, so most of it is entertainment to me.

Second, He never said the timing chain broke.

Third, he said that he could be wrong and it's just his assumption of what may have happened, which was the timing chain being too tight that could effect things.

Fourth, whether it's intended or accidental you are putting words in someones mouth when you rely on your misunderstood memory. Even I need to fact check myself sometime so I don't make false or misinformed claims. And remember, there are other content creators here, you could accidentally make false claims about them too.
You're wasting your breath. That guy has a total hate for Tony Defeo that defies logic.
 
The problem is finding R/T heads. You’d be lucky to find them to start with. I was with the above heads and traded a set of Edelbrock heads for them. This was the direction of the other guy and I have a curiosity about ‘em. The above are the 2.02/1.60 heads. They flowed pretty good for a OOTB casting.
 
The problem is finding R/T heads. You’d be lucky to find them to start with. I was with the above heads and traded a set of Edelbrock heads for them. This was the direction of the other guy and I have a curiosity about ‘em. The above are the 2.02/1.60 heads. They flowed pretty good for a OOTB casting.
Good looking heads.
 
Good looking heads.

I’m stalled on them like all projects around here - LMAO - grooooooannnn - LOL

They will be coupled with a small Howard’s cam. 220*’s@050 - 540 lift - 108/104 installed intake on a stock 5.9 short block with a RPM/750/Hooker 1–3/4 Super Comp headers - 2-1/2 exhaust.
2500 stall 727/3.55’s in a ‘79 Magnum.
 
I’m stalled on them like all projects around here - LMAO - grooooooannnn - LOL

They will be coupled with a small Howard’s cam. 220*’s@050 - 540 lift - 108/104 installed intake on a stock 5.9 short block with a RPM/750/Hooker 1–3/4 Super Comp headers - 2-1/2 exhaust.
2500 stall 727/3.55’s in a ‘79 Magnum.

Sounds stout enough to be a legit coffee spiller :thumbsup:
 
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