Goals and advice needed

[FlamesAreWicked]

If looking to do 12's I'd go 360/5.9l but can be done with a 318.

Here's an article what it took to do high 12's (12.76/103mph) with a 318 and dyno results.

https://www.hotrod.com/articles/mopp-0311-318-engine-buildup-and-dyno-test

Test 1-Stock 318 with two-barrel carburetor, 1 5/8-inch Hedman headers, and 3-inch exhaust system with mufflers.Test 2-Rebuilt 318 with 9.8:1 compression ratio, pocket-ported 318 heads, 340 cast-iron intake manifold, 625-cfm AVS carburetor, and Giles Performance single-pattern camshaft.Test 3-Same as test 2, but with Giles Performance dual-pattern camshaft.Test 4-Same as test 3, with ported 360 heads.Test 5-Same as test 4, but with 360 cast-iron intake manifold and 750-cfm Thermo- Quad carb.

RPM	Test 1	Test 2	Test 3	Test 4	Test 5
	CBT	CHp	CBT	CHp	CBT	CHp	CBT	CHp	CBT	CHp
2500	305	145	326	155	347	165	360	171	364	173
2750	303	158	336	176	357	187	369	193	371	194
3000	297	170	338	193	364	208	373	213	377	215
3250	286	177	338	209	366	226	375	232	379	234
3500	277	184	233	222	365	243	273	249	378	252
3750	262	187	337	241	363	259	371	265	377	269
4000	246	187	343	261	369	281	378	288	385	293
4250	230	186	343	278	270	299	381	309	388	314
4500	214	184	340	292	365	313	380	326	388	333
4750	197	179	331	299	356	322	372	336	380	344
5000	180	171	376	301	341	324	362	345	371	353
5250	163	163	298	298	324	324	346	346	357	357
5500	146	153	279	293	306	321	330	345	339	355
5750	290	317	312	341	321	352
6000	271	310	295	337	302	345

CBT= Corrected brake torqueCHp= Corrected horsepowerHorsepower and torque corrected to 29.92 inches/Hg barometer, 60 degrees, with dry air.

To me looks like 5750 and 6000 rpm's are in the wrong boxes and should be moved over 5 spots.

Looking at the chart on the hot rod website.. seems odd to have such a spike from 5500 to 5750? Also what’s a safe rpm to spin a stock 318 to? I figured 5000-5300 would be it ?

 

[273]

Looking at the chart on the hot rod website.. seems odd to have such a spike from 5500 to 5750? Also what’s a safe rpm to spin a stock 318 to? I figured 5000-5300 would be it ?

When they put there magazines online some of the numbers on the charts got moved I put them where I'm pretty sure they belonged.

RPM	Test 1		Test 2		Test 3		Test 4		Test 5
	CBT	CHp	CBT	CHp	CBT	CHp	CBT	CHp	CBT	CHp
2500	305	145	326	155	347	165	360	171	364	173
2750	303	158	336	176	357	187	369	193	371	194
3000	297	170	338	193	364	208	373	213	377	215
3250	286	177	338	209	366	226	375	232	379	234
3500	277	184	233	222	365	243	273	249	378	252
3750	262	187	337	241	363	259	371	265	377	269
4000	246	187	343	261	369	281	378	288	385	293
4250	230	186	343	278	270	299	381	309	388	314
4500	214	184	340	292	365	313	380	326	388	333
4750	197	179	331	299	356	322	372	336	380	344
5000	180	171	376	301	341	324	362	345	371	353
5250	163	163	298	298	324	324	346	346	357	357
5500	146	153	279	293	306	321	330	345	339	355
5750					290	317	312	341	321	352
6000					271	310	295	337	302	345

CBT= Corrected brake torqueCHp= Corrected horsepowerHorsepower and torque corrected to 29.92 inches/Hg barometer, 60 degrees, with dry air.

Test 1-Stock 318 with two-barrel carburetor, 1 5/8-inch Hedman headers, and 3-inch exhaust system with mufflers.Test 2-Rebuilt 318 with 9.8:1 compression ratio, pocket-ported 318 heads, 340 cast-iron intake manifold, 625-cfm AVS carburetor, and Giles Performance single-pattern camshaft.Test 3-Same as test 2, but with Giles Performance dual-pattern camshaft.Test 4-Same as test 3, with ported 360 heads.Test 5-Same as test 4, but with 360 cast-iron intake manifold and 750-cfm Thermo- Quad carb.

 

[273]

I figured 5000-5300 would be it ?

318 got a strong bottom end people have spun them fairly high 6000+ rpms.

 

[junkyardhero]

Also what’s a safe rpm to spin a stock 318 to? I figured 5000-5300 would be it ?

55 is "safe" but i wouldn't press much past that without better rod bolts and knowing the bottom end: rods, pistons, rings, bearings-- types and clearances, and oil pump/pick up.

well put together they're good to 6+ all day

 

[273]

If you look after I fixed the dyno graph that 318 generally peaking at 5250 rpm no need to rev it too much pass peak.

 

[FlamesAreWicked]

If you look after I fixed the dyno graph that 318 generally peaking at 5250 rpm no need to rev it too much pass peak.

I wondered about that.. even if ya could spin it 6000 on stock parts.. your power waved bye bye long before that lol

 

[mygasser]

I wondered about that.. even if ya could spin it 6000 on stock parts.. your power waved bye bye long before that lol

hence my mention of more cam amplifying the headers/exhaust and 4 barrel swaps

 

[Mattax]

I wondered about that.. even if ya could spin it 6000 on stock parts.. your power waved bye bye long before that lol

It depends on the build and what you are trying to do.
If you are really going to run quarter mile, then we generally shift a bit past peak Hp and try to get through the finish lights near peak Hp. If the engine is more torque focused, and the car has good chassis and some sort of sticky tire, then you can get some of the et off the line. When running street tires, where we get poor traction then the game is more about making use of the hp.

As an example let's look at the wheel power produced by Zebra Dart with the 318. This is a road course car, that was also autocrossed and driven to events. Baseline is the engine as built by the previous owner with machine work done by Dick Ott, and had a cam selected to produce power well past peak. @CPDave bought the car and continued its development. Lamehorse Racing

Anyway, the points here are
1. Changing from 273 exhaust manifold to headers unlocked the potential of that of that original combination with power increase from as low as the dyno would show to well past peak.
2. Depending on gearing and tires, a shift point past peak might well be warrented. This happens to be a 2.66:1 4 speed car with a 3.55 diff. It was very responsive off the line when I drove it.
3. A good valve job and some head work (if legal for your class) can go a long way. IIRC the new heads also bumped the CR slightly.

 

[skep419]

This is a bit of a loaded post since it’s not as simple as a single question and answer. While the stock 318 in my 68 Dart runs well I know investing the same amount of money in a mag 5.9 will yield much better results. My goals aren’t really achieving a specific horsepower number. I’d like enough power to maybe get my car in the 12.8-12.9 in the heat. I say that goal because in Louisiana, it’s warm/hot most of the year.

I found a couple of 5.9 magnum options locally. One at a U-pull it for $500 (including the price of them pulling it for me). It’s in a 2000 Durango 4wd. Miles are unknown. It looked pretty clean and the only concern was the oil cap was missing because of fear of water getting in it. Second option is one from a private seller close to where I live that’s also in a Durango. Supposedly it has 120k miles on it and an older couple owned it. The seller said that it was running and driving recently but he’s parting it out and the transmission has been sold out of it currently. He wants $350 for it and he’s gonna pull it.

With all that being said.. what kind of power will I need to be in that range of ET? I have a 4 speed and a 3.55 gear. Could I even get my 318 to do those sort of numbers without totally just setting money on fire?.. I know the stock 5.9 can get to mid 300hp relatively easy.. main thing would be reliable, fun to drive, and if it can bust off a high 12 in the 1320… I’d say mission accomplished..

The appeal of the 120k mile motor (if he’s not full of crap) that it’s still fresh enough to not need a full overhaul.. I know these engines can possibly last well beyond that miles wise.. machine shops locally are few and far between where I live..

Stuff like this can snowball fast and in the end, it would of been better to do XYZ instead..

I wish I could foot the bill for a blueprint 408 to drop in but..if I can achieve my goals much more affordably, I will.

Any advice is appreciated… I’ve never dug into the innards of an engine but I’m confident I’m capable should I need to. I know the heads are prone to crack and the cost of stock replacement heads aren’t quite as cheap as they used to be (like everything these day).. almost better off with promaxx heads or something if that’s the case

I'm always going to pick the 5.9 Magnum junkyard engine. Send the cam to Oregon cams, get a hughes spring set, carb intake, weld up a factory electronic distributor to get the curve.

Let it run what it runs and have fun. Generally every upgrade made to make it go faster is a takeaway from streetability/durability.