Big horsepower 318 builds

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AndyF said:
I watched Bob Mazzolini race his 318 years ago. Cast iron heads, low compression pistons, QJet carb. Made more than 500 hp, ran low 10's in a Sebring. Very high dollar engine with a high dollar transmission and a high dollar car. It would yank the front end and go. He used a cast crank since it was lighter. Not sure on the RPM, well north of 7K.

I think the compression ratio in Bob's engine was 8.9 and he used some 360 cast iron heads but I don't recall the part number. Car was around 3200 lb and it ran low 10's. When I saw Bob's car run it really woke me up to the fact that there is a big difference between what most people think and what is possible with some dedicated effort.
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Well put !!!
 
That is very true. Most people just want to our base parts and slap together a combo and go.
 
1Badcolt said:
LA - benefits
High nickel alloy [pre-1977]
High cam centerline height of 6.125"- Much higher than other small blocks and also higher than
the Mopar big blocks including the Hemi 426
Stock 6.123 inch rods the teen offers a rod ratio the competition would die for [1.85:1]
Valves are inclined at a advantageous 18 degree angle
Higher cam centerline clears long strokes easily and therefore allows more displacement
Chrysler engineers made a Master piece.
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Yes they did. So why did the cancel it? Was it such a good engine that Chrysler was not making any "after warranty" service money?
 
harrisonm said:
Yes they did. So why did the cancel it? Was it such a good engine that Chrysler was not making any "after warranty" service money?
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They could of easily made the Magnum stronger and added heads for 500 plus hp, but the hemi name just a better sales tool. The 5.7 hemi is basically a 318 with a 360 crank and hemi type heads. Rotating assembly ain’t that different from LA/Magnum.
 
273 said:
Don't think I'd ever would build a 500 hp 318, The only ride I could think of putting one behind if I was gonna build a gutted corner carver with a six speed and at least 4.56 gears, but I'd probably hold out for a 340 block still. To me once you start going over 425-450 hp I'd start thinking Big Block.

To me power ranges
/6 150-250hp
273 200-350hp
318 250-400hp
340/360 300-450hp
408/416 400-550hp
383/400 400-550hp
440-499 450-650hp
500 plus 600 plus hp
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HP #'s are just that, just #'s, only way to get those is calculating Torque and RPM ! In the case of making Huge HP #'s with ANY SB, you are going to have to turn RPM and this where the SB's always ran into problems, not that they can't or won't do it but they will not live doing it. The blocks crack in the front main webs because of the iron missing where the oil passages are drilled out. That very reason is why 340's are as hard as they are to find mostly. At least ones that are not cracked. Many people don't even realize their blocks are cracked there. People destroyed them building them to turn too many RPM's. For all the factory did to make them so good at making HP, they dropped the ball in the oiling design. If I could only get ahold of a block that had not had the front passages drilled?
 
Bret Tschacher said:
HP #'s are just that, just #'s, only way to get those is calculating Torque and RPM ! In the case of making Huge HP #'s with ANY SB, you are going to have to turn RPM and this where the SB's always ran into problems, not that they can't or won't do it but they will not live doing it. The blocks crack in the front main webs because of the iron missing where the oil passages are drilled out. That very reason is why 340's are as hard as they are to find mostly. At least ones that are not cracked. Many people don't even realize their blocks are cracked there. People destroyed them building them to turn too many RPM's. For all the factory did to make them so good at making HP, they dropped the ball in the oiling design. If I could only get ahold of a block that had not had the front passages drilled?
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Yes your correct hp is just a calculation of the combined output of torque and rpm. And since torque is mainly a results of displacement we'll need to turn up the rpm, If you look at hp per displacement in each of those examples especially the small blocks we're talking about 1.25hp per cid which should be able to be made at a peak of 6000 rpm give or take a few hundred rpm which is a street strip territory type engine but far from full race and a crack the block type thing. That's why to me, that's the upper end for those engine some people might to love to make peak power a 500/1000 or more rpm higher so they will get a lot more power out of each many would like peak power at a lower rpm so less power why the hp range I gave.
 
Most street guys want around 0.9-1.1 hp per cid for a built street performance engine so for a 365 would be 330-400 hp and peak hp rpm of 4500-5500 rpm ish. To me 1.1-1.3 hp per cid is a street strip engine. Above that depending on the person you start to get into more of a race engine.
 
I’m setting my sights on putting 325hp to the tires with my 318. I may not make it prior to adding boost... but I do plan on trying! With some tweaks it’s a shoe in for 310 or so at the moment.
 
AustinGriggs said:
I’m setting my sights on putting 325hp to the tires with my 318. I may not make it prior to adding boost... but I do plan on trying! With some tweaks it’s a shoe in for 310 or so at the moment.
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Depends on which heads your gonna use, don’t listen to these nay sayers obviously if you give a 318 enough air flow and Cr it’s gonna be able to make power.
 
273 said:
Depends on which heads your gonna use, don’t listen to these nay sayers obviously if you give a 318 enough air flow and Cr it’s gonna be able to make power.
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I’m gonna stick with my J-heads for that goal but if I throw out the desire for boost on this engine I plan to move over to my R/T head which I haven’t started hacking on yet. I will pump my prediction/hopes/dreams up to the magical 340whp....
 
1.88 j heads then your probably stuck around 360-380 NA hp with moderate cam and Cr, 325 wheel hp is probably around 400-425 hp crank. Now if you port you might get close.
 
273 said:
1.88 j heads then your probably stuck around 360-380 NA hp with moderate cam and Cr, 325 wheel hp is probably around 400-425 hp crank. Now if you port you might get close.
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We shall see, I’m dumb enough to embark on all this. I am putting in alittle more cam after race day in October. As far as my J heads they are 2.02 and I did spend a number of hours porting them to get to the current 293whp it’s at now.
 
AustinGriggs said:
We shall see, I’m dumb enough to embark on all this. I am putting in alittle more cam after race day in October. As far as my J heads they are 2.02 and I did spend a number of hours porting them to get to the current 293whp it’s at now.
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a 318 turning 7500 rpms needs more air than a 390 turning 5800,..id go ahead with them R/T's!!
 
dirty white boy said:
a 318 turning 7500 rpms needs more air than a 390 turning 5800,..id go ahead with them R/T's!!
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If not for the moderate probability of me destroying the whole thing during the tuning process once turbocharged; I’d go that route now, but it runs good as is and I don’t want to go too crazy as it’s kinda ready for boost now-ish.
 
toolmanmike said:
How about a discussion about a naturally aspirated, no nitrous, stock stroke, 318 on gas or alcohol. I have read quite a few posts lately about 500+ horse teens that I find hard to believe.
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Well over 600 hp back in the early 80's. It's not a new thing.
 
dirty white boy said:
Your HP is 407.23 computed from your vehicle weight of 3300 pounds and ET of 11.70 seconds.
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Building 400 is not that hard then, my 318 is 9.4 to 1 with not a big cam, street engine drove it to the track, with some compression and fairly good head, i do not see why 500 cannot be done, my engine is nothing special stock rods and hyper piston's.
 
ValiantRacing said:
Building 400 is not that hard then, my 318 is 9.4 to 1 with not a big cam, street engine drove it to the track, with some compression and fairly good head, i do not see why 500 cannot be done, my engine is nothing special stock rods and hyper piston's.
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Wouldn't be that hard, trick flows with 10.5:1 285-295 ish cam with the right intake/carb and exhaust but for most having to spin to about a 7500 rpm for peak power is on the high side and needing 4.88-5.13 + gears and 5000-6000 + rpm stall is a little much. A 408 would do it around 6000 rpm a 440 @ 5500 rpm, 500+ @ 5000 rpm.
 
You wouldn’t need that much.
273 said:
Wouldn't be that hard, trick flows with 10.5:1 285-295 ish cam with the right intake/carb and exhaust but for most having to spin to about a 7500 rpm for peak power is on the high side and needing 4.88-5.13 + gears and 5000-6000 + rpm stall is a little much. A 408 would do it around 6000 rpm a 440 @ 5500 rpm, 500+ @ 5000 rpm.
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273 said:
Wouldn't be that hard, trick flows with 10.5:1 285-295 ish cam with the right intake/carb and exhaust but for most having to spin to about a 7500 rpm for peak power is on the high side and needing 4.88-5.13 + gears and 5000-6000 + rpm stall is a little much. A 408 would do it around 6000 rpm a 440 @ 5500 rpm, 500+ @ 5000 rpm.
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If it was so easy....there should dozens of them being build on here....LOL
 
70aarcuda said:
If it was so easy....there should dozens of them being build on here....LOL
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Yes once you go under 340 cid and a 4” bore physics goes out the window, and a engine can’t be built to make hp.
Just cause people don’t doesn’t mean they can’t, 400M we’re considered boat anchors until they started sweeping up the competition in engine build competition, one of the builders on this site got 473 hp out of a 273 @ 7900 rpm, with ported EQ heads. Don’t understand how people are ok with 340/360 making power but as soon as you do those same things to a 318 it can’t happen ??

and yes rumblefish360 7500 might be a tad high there’s 302 and 5.3ls getting done by 7000 rpm, went with worse case scenario.
 
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273 said:
Yes once you go under 340 cid and a 4” bore physics goes out the window, and a engine can’t be built to make hp.
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Complete hogwash, BS to the highest level.
273 must be joking here.
Just cause people don’t doesn’t mean they can’t, 400M we’re considered boat anchors until they started sweeping up the competition in engine build competition, one of the builders on this site got 473 hp out of a 273 @ 7900 rpm, with ported EQ heads. Don’t understand how people are ok with 340/360 making power but as soon as you do those same things to a 318 it can’t happen ??
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Ahhhhh he was he was!!!

and yes rumblefish360 7500 might be a tad high there’s 302 and 5.3ls getting done by 7000 rpm, went with worse case scenario.
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The problem with the statement was the build was overkill IMO as well as the rpm at which it is obtained & that people that don’t know will take to the bank as fact.
 
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