When you say 256-252 duration, are you saying at .050" or advertised duration? I chkd Lunati websife out and the advertised duration is lower than .050 duration.
Thanks
Steve
Thanks
Steve
318 build with XE268 AND 302 heads
- Thread starter megavites
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stixx
Well-Known Member
Great story from the past! And so true...
fratzog lover
Well-Known Member
Advertised.
nm9stheham
Well-Known Member
Spot on... I am talking about advertised duration. Advertised duration numbers will always be larger than the .050" duration numbers, since advertised are measured at lifts from .004" to .010" or even .015" (depends on cam type and mfr).
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Krooser
Building Chinese Free Engines since 1959...
Does anyone care about running these generic Chevy grind cams in a Mopar with a .904 lifter? Or doesn't it matter on the street? Just curious... seems you are leaving a bunch of fun on the table.
fratzog lover
Well-Known Member
Ok, I will volunteer a choice for the OP
Hughes Engines
Or leave the driveline alone.
Hughes Engines
They are smart and don't put advertisrd duration specs. Good choices.
nm9stheham
Well-Known Member
When you look in the Crane Master Profile catalog, the lobes types are separated out by lifter diameter...hint, hint.
megavites
Well-Known Member
so long story short...I came upon a free 318 block with heads today. I'm going to take and rebuild these low compression heads and go with the Whiplash cam.
Over the winter, I'm going to rebuild this 1970 block with KB167 pistons and the 302 heads. Now its just a matter of
picking the right stick to run in this high compression SB. I'm guessing 10:1 comp.
What would be your choice of cam at that point? TC stall will match and rear will be 3.55.
Over the winter, I'm going to rebuild this 1970 block with KB167 pistons and the 302 heads. Now its just a matter of
picking the right stick to run in this high compression SB. I'm guessing 10:1 comp.
What would be your choice of cam at that point? TC stall will match and rear will be 3.55.
C130 Chief
Mechanical Genius
The 70 block, KB167's @ zero deck, 302 heads w/bigger valves and basic port job would be a reasonable place for the XE268. You'd have a fairly tight quench motor with an SCR of 10:1 and a DCR just under 8.0:1.
nm9stheham
Well-Known Member
Now you're talking LOL! What are you going to be using the engine and car for?Cam selection (and actually ALL engine build parameters) flow from that.
BTW, you're Static CR will be around 9.5 with STOCK deck height, KB167's, 64 cc combustion chambers, and the Mr Gasket 1121 G head gaskets. Quench gap would be .040" + or - with that; the variations would be due to piston-to-deck variations.
The above post refers to 'zero decked' pistons to get to around 10:1, but then you cannot run the 1121 G head gaskets unless you are very brave and control the piston to deck height very tightly. That brave setup would get you to around 9.8 with the 64 cc chambers.
The next step up in reasonably priced gasket thickness would be a Felpro 1008 .039", and with zero decked pistons, SCR would then be around 9.5. So if you want to hit that 10.0 SCR mark with those gaskets, then you'll need to get the combustion chamber volume down to around 60 cc's with some head milling.
But again, it all goes back to the application and your plans for the engine/car.
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nm9stheham
Well-Known Member
I am scratching my head and wondering why fewer specs is smarter....??
LOL. Fewer specs is not smart but too many specs that don't mean much isn't smart either. There is a lot of confusion between advertised and @.050 duration. Where did the old "3/4 race" go to? Lol
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XE268 but you will want that torque converter 2200-2500. That is the same as my build but I never got the TC and it took a lot of tuning to get it to run right. It will have a great lope at idle too. Good luck!
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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IMO
the cam should fit the application.
One should not put a stick in an engine and then try and make that engine fit an application. Why are we building engines with power peaks at 5500, and shift rpms at 6500 to 6800, for a streeter that spends 98% of its life at sub-4000? And to make it work, we put 3500 TCs in 'em and 3.55 gears. That seems just so wrong to me.
If we spent all that engine money on decent torque multiplication, we would have so much better a street combo.
First gear in a 904/3.55s goes to 65 mph.Sure it's quick.But this is how we do it; we launch with a 3000 plus TC and force that engine to pull thru hundreds of low-power rpms to finally arrive at peak horsepower, and then past, and way down the other side of the curve. So the average hp during the run, ends up dismal. But we are so excited.
Imagine a snowmobile system with a CVT where the engine pops up to peak hp and stays there all the way from zero mph to 65 mph. That engine, in order to make the same average hp could be a waaay tamer item.
Below is a typical hp graph. I have no idea where it comes from, but it says 318 on it,lol, and it peaks around 5700, kindof typical for some street engines.
Notice the big torque hole below 4200.
Below 4200 is where this engine in a streeter would spend most of it's life.
Notice the torque doesn't even start until 3800 ish.
Notice the power peak. With an automatic transmission, this engine might want to be shifted up near 7500,to come in at 4450ish. This would average the power out at about 325.
>But say this was for a 1-gear run.
You would want a 4200 TC to cash in on where the torque really starts.And you would want to gear the car to run up just past the power peak, say to 6200. 3.23s it would be, with a 2.45 low.
This would give you a light-speed zero to 65 mph.
Now, imagine driving this beast, 95%: a) not WOT, and b) not over 4000 rpm, and c)most of the time at PT,part throttle,and d) occasionally cruising 65 mph, and e) try to imagine how much fuel this beast is gonna drink.
>Now imagine If you had a CVT that set at about 5700, the power delivery would be stuck at 365ish for the entire run. It would be way quicker.
So try to imagine detuning the engine to 325 hp to put out the same average power as that HO unit. It would still be just as quick. But go look at the hp line. Check out what rpm it takes in this engine, to make 325 hp. It looks to be 4800. So in other words if the CVT was kept to 4800, it would be just as quick as the 2.45low/3.23 combo.Now, the CVT idea is an idealism
>Imagine your teener pulling two gears to 65 mph, this is about the best we can do with the trannys available to us. And lets make it a manual trans cuz that is the only way to keep the little teener on the pipe.
And because we can see already that this is gonna take a deep rear gear, lets choose the 2.66 tranny for it's reasonable splits.
We are gonna need a bit more than 4800 to stay on par with the CVT so lets choose arbitrarily a 5200 shift rpm.
Look on the graph to 5200. This is about 350 hp.
The tranny ratios are 2.66-1.91-1.39-1.00
A little math kicks out 3.37 gears, which I will round up to 3.55s and increase the rpm in compensation.
I get 65= 5475 rpm. So since the hp peak at this power level will be pretty flat, I suggest that this 5475 can be 475 over the peak number and call the peak at 5000. Back to the graph and 5000 looks like 335 hp.
Now lets see how this works
Your left leg is quivering on the start line, as you get ready to blast off. You bring up the revs to 3900 where the torque peaks. The light turns green and it's go time. You dump the clutch and the car launches and its hammer down time. You get some wheel spin and you hold it at 4500 to 5000 until the tires stop spinning. The revs climb to 5500 and you have just crested 46 mph. You slam it into second and about 2 seconds later you are cresting 65mph at about 5500. Shazzam that was quick!
Your engine was at or over 3900 right out of the gate, with a momentary dip on the 1-2 shift to 3900ish. Looking on the graph this average hp comes in a 300@4700.
Now about this engine;.
With a 5000 hp peak,the torque peak will come in at around 3750.
This combo will get pretty good fuel economy, The starter gear is 9.44, not too bad. And with 3.55s will cruise at 65=2867
32mph will be 3670 in first, just below peak torque. So when you downshift at 32, you will be blasting off.
The torque production at lower than 3750 will be prodigious with this small cam; gone will be the soft spot.
Imo, This is how to match the engine to to the street-application, with plenty of torque production, and torque multiplication.
And you don't need a big engine.
Obviously a bigger engine will be a little quicker in the zero to 65 zone, but we are talking what? One half second? And the bigger engine,to be effective, will need to spend way more money on trying to put the power to the pavement.
I like the analogy of shooting a rabbit with a .22 or a .303. How dead do you need the rabbit to be?
If you can only fit 275s back there........ What's the sense in a streeter having much over 300/350 hp, the tires spin all the way to the speed limit anyway...
the cam should fit the application.
One should not put a stick in an engine and then try and make that engine fit an application. Why are we building engines with power peaks at 5500, and shift rpms at 6500 to 6800, for a streeter that spends 98% of its life at sub-4000? And to make it work, we put 3500 TCs in 'em and 3.55 gears. That seems just so wrong to me.
If we spent all that engine money on decent torque multiplication, we would have so much better a street combo.
First gear in a 904/3.55s goes to 65 mph.Sure it's quick.But this is how we do it; we launch with a 3000 plus TC and force that engine to pull thru hundreds of low-power rpms to finally arrive at peak horsepower, and then past, and way down the other side of the curve. So the average hp during the run, ends up dismal. But we are so excited.
Imagine a snowmobile system with a CVT where the engine pops up to peak hp and stays there all the way from zero mph to 65 mph. That engine, in order to make the same average hp could be a waaay tamer item.
Below is a typical hp graph. I have no idea where it comes from, but it says 318 on it,lol, and it peaks around 5700, kindof typical for some street engines.
Notice the big torque hole below 4200.
Below 4200 is where this engine in a streeter would spend most of it's life.
Notice the torque doesn't even start until 3800 ish.
Notice the power peak. With an automatic transmission, this engine might want to be shifted up near 7500,to come in at 4450ish. This would average the power out at about 325.
>But say this was for a 1-gear run.
You would want a 4200 TC to cash in on where the torque really starts.And you would want to gear the car to run up just past the power peak, say to 6200. 3.23s it would be, with a 2.45 low.
This would give you a light-speed zero to 65 mph.
Now, imagine driving this beast, 95%: a) not WOT, and b) not over 4000 rpm, and c)most of the time at PT,part throttle,and d) occasionally cruising 65 mph, and e) try to imagine how much fuel this beast is gonna drink.
>Now imagine If you had a CVT that set at about 5700, the power delivery would be stuck at 365ish for the entire run. It would be way quicker.
So try to imagine detuning the engine to 325 hp to put out the same average power as that HO unit. It would still be just as quick. But go look at the hp line. Check out what rpm it takes in this engine, to make 325 hp. It looks to be 4800. So in other words if the CVT was kept to 4800, it would be just as quick as the 2.45low/3.23 combo.Now, the CVT idea is an idealism
>Imagine your teener pulling two gears to 65 mph, this is about the best we can do with the trannys available to us. And lets make it a manual trans cuz that is the only way to keep the little teener on the pipe.
And because we can see already that this is gonna take a deep rear gear, lets choose the 2.66 tranny for it's reasonable splits.
We are gonna need a bit more than 4800 to stay on par with the CVT so lets choose arbitrarily a 5200 shift rpm.
Look on the graph to 5200. This is about 350 hp.
The tranny ratios are 2.66-1.91-1.39-1.00
A little math kicks out 3.37 gears, which I will round up to 3.55s and increase the rpm in compensation.
I get 65= 5475 rpm. So since the hp peak at this power level will be pretty flat, I suggest that this 5475 can be 475 over the peak number and call the peak at 5000. Back to the graph and 5000 looks like 335 hp.
Now lets see how this works
Your left leg is quivering on the start line, as you get ready to blast off. You bring up the revs to 3900 where the torque peaks. The light turns green and it's go time. You dump the clutch and the car launches and its hammer down time. You get some wheel spin and you hold it at 4500 to 5000 until the tires stop spinning. The revs climb to 5500 and you have just crested 46 mph. You slam it into second and about 2 seconds later you are cresting 65mph at about 5500. Shazzam that was quick!
Your engine was at or over 3900 right out of the gate, with a momentary dip on the 1-2 shift to 3900ish. Looking on the graph this average hp comes in a 300@4700.
Now about this engine;.
With a 5000 hp peak,the torque peak will come in at around 3750.
This combo will get pretty good fuel economy, The starter gear is 9.44, not too bad. And with 3.55s will cruise at 65=2867
32mph will be 3670 in first, just below peak torque. So when you downshift at 32, you will be blasting off.
The torque production at lower than 3750 will be prodigious with this small cam; gone will be the soft spot.
Imo, This is how to match the engine to to the street-application, with plenty of torque production, and torque multiplication.
And you don't need a big engine.
Obviously a bigger engine will be a little quicker in the zero to 65 zone, but we are talking what? One half second? And the bigger engine,to be effective, will need to spend way more money on trying to put the power to the pavement.
I like the analogy of shooting a rabbit with a .22 or a .303. How dead do you need the rabbit to be?
If you can only fit 275s back there........ What's the sense in a streeter having much over 300/350 hp, the tires spin all the way to the speed limit anyway...
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Howdy
Just finished building my 318.
Specs are
- 318 +.040" (3.95" bore)
- block zero decked
- aeroflow alloy heads/65cc/I-2.02" E-1.6" valves
- comp cams xe268 hydr flat tappet
- keith black 167 pistons
- 273 adjustable rocker gear w/ Toyota 4k pushrods
- 2100rpm stall convertor
- standard 318 exhaust manifolds at the moment
- compression is around 9.5:1
- hei ignition
- stock 3.23:1 gears
- 904 auto
- LD4B
- 600cfm Holley
Still running the motor in, but pulls nicely in the mid rpm on wards. Nice cruiser motor with a bit of go.
Video of it running
Andrew
Just finished building my 318.
Specs are
- 318 +.040" (3.95" bore)
- block zero decked
- aeroflow alloy heads/65cc/I-2.02" E-1.6" valves
- comp cams xe268 hydr flat tappet
- keith black 167 pistons
- 273 adjustable rocker gear w/ Toyota 4k pushrods
- 2100rpm stall convertor
- standard 318 exhaust manifolds at the moment
- compression is around 9.5:1
- hei ignition
- stock 3.23:1 gears
- 904 auto
- LD4B
- 600cfm Holley
Still running the motor in, but pulls nicely in the mid rpm on wards. Nice cruiser motor with a bit of go.
Video of it running
Andrew
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nm9stheham
Well-Known Member
That is a nice motor...it has that 9-to-10 SCR, 268-cammed sound to it, with a certain sharp 'bark' to the exhaust note. Headers would just add to everything.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
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- 25,688
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Key words zero-decked and 9.5 Scr. That will make a nice runner
And like nm9 says "headers would just add to everything".That cam wants headers to take advantage of the overlap cycle. Its only 52* but, with manifolds, the cycle is completely stifled. And that cycle begins working at about 2000rpm and increases effectiveness all the way to peak torque, and then to shift rpm.
If you are only gonna cruise it, with occasional power-bursts,then I wouldn't worry about it.
Combo looks good,especially if it pulls those 3.23s, with just a 2100TC. Very good.
And like nm9 says "headers would just add to everything".That cam wants headers to take advantage of the overlap cycle. Its only 52* but, with manifolds, the cycle is completely stifled. And that cycle begins working at about 2000rpm and increases effectiveness all the way to peak torque, and then to shift rpm.
If you are only gonna cruise it, with occasional power-bursts,then I wouldn't worry about it.
Combo looks good,especially if it pulls those 3.23s, with just a 2100TC. Very good.
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