What does it take to get 350-400hp out of a 'late model L48?
#1
Team Owner
Thread Starter
What does it take to get 350-400hp out of a 'late model L48?
Having a friendly discussion in which I stated a decent duration cam, intake, and headers would net 350hp. I was told "No way", not I relaize the compression was 8:2 maybe if the heads were shaved one thousandth, and a thinner gasket installed to raise compression might do it?
So you L48 owners, what did/does it take to make 350-400hp??
So you L48 owners, what did/does it take to make 350-400hp??
Last edited by Corey_68; 08-13-2005 at 07:04 PM.
#2
my l-48 was tore down and turned into a 383 motor ,10.5 to 1 comp,488 lift cam,, preformer intake,, 670 holly , intake valves opened to 2.02 intake /165 exh
Last edited by carl a; 08-13-2005 at 07:18 PM.
#3
Race Director
You will not get there with stock L48 heads, you need better heads and 10:1 CR, cam, intake, exhaust and carb, basically the whole nine yards
#4
Le Mans Master
Originally Posted by MotorHead
You will not get there with stock L48 heads, you need better heads and 10:1 CR, cam, intake, exhaust and carb, basically the whole nine yards
Now, my combo is:
L-48, .030" over for 355 cubes
Edelbrock RPM heads with 64cc chambers, approx 10:1 compression
Edelbrock 2101 Performer (my chokepoint) with Lars' tuned Q-Jet
Hooker sidepipes (primaries are a little on the large side)
Cam: Crane hyd roller 214/222 @.050", .488/.509 lift
Car pulls hard from 2000 and I limit myself to about 5500/6000 rpm.
BTW: Desktop Dyno says 430 HP at 6000 rpm and 430 ft/lbs at 4000 rpm. I'll be conservative and say I have 375 or so.
Last edited by SteveG75; 08-13-2005 at 07:48 PM.
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kmcc505 (03-01-2024)
#5
Originally Posted by Corey_68
So you L48 owners, what did/does it take to make 350-400hp??
An Edelbrock Performer RPM package or its equivalent.
I went the "or its equivalent" route (I can go into greater detail if you want, but the RPM package is what it amounts to) and figure I'm at 400 or so at the flywheel. That number is just a guess, but I'll have to say that it makes for a lively ride that I've been happy with for quite some time.
Last edited by 45ACP; 08-13-2005 at 07:56 PM.
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kmcc505 (03-01-2024)
#6
Melting Slicks
First, look at what the 350hp engines had. That should be a good starting point. "Bigger' cam, better heads, and more compression.
Swap out the heads for the Vortecs which are an improvemnet over the old double humps. They will also raise the compression. For more compression a thinner head gasket could be used and it should come up in the to 10:1 range. Change the cam as well as the intake which is required for the heads. It should out do the 350hp rating from the old days..
Swap out the heads for the Vortecs which are an improvemnet over the old double humps. They will also raise the compression. For more compression a thinner head gasket could be used and it should come up in the to 10:1 range. Change the cam as well as the intake which is required for the heads. It should out do the 350hp rating from the old days..
#7
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I have my original block L48-Trick flow twisted wedge heads,comp cam 268,rpm air gap intake,1.6 roller rockers,msd ignition,Holley avenger 670 ,dynoma headers,2 1/2 in dual exhaust with x pipe.Dont know the hp but it runs good
#9
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To get hp you compromise low end hp. This compromise is mostly done with the cam. Low/mid/high. Where do you want it? Low/mid or mid/high. You can't have all three. Sometimes not even 2.
Better breathing is done with intake and exhaust- it improves the cam selected.
I doubt you can get this level of hp without drasticly compromising low/mid performance. It can be done but now your talking about a single purpose drag motor with a power spike and little else. So maybe you can get 350 hp at 7300-7600 and almost nothing everywhere else.
This could be done with 1 additional componant. A blower or nitrous. Both de-compromise intake/exhaust/cam compromises made.
Unless they made great improvements on that desktop dyno I don't think its worth anything. Change different stuff on it and it makes rediculous claims.
Compare those numbers to a BB and it did it with a radical cam and high compression. Roller cam maybe but isn't the duration low for a SB? I don't know.
I played with it for a while and found it to be weird.
Better breathing is done with intake and exhaust- it improves the cam selected.
I doubt you can get this level of hp without drasticly compromising low/mid performance. It can be done but now your talking about a single purpose drag motor with a power spike and little else. So maybe you can get 350 hp at 7300-7600 and almost nothing everywhere else.
This could be done with 1 additional componant. A blower or nitrous. Both de-compromise intake/exhaust/cam compromises made.
Unless they made great improvements on that desktop dyno I don't think its worth anything. Change different stuff on it and it makes rediculous claims.
Compare those numbers to a BB and it did it with a radical cam and high compression. Roller cam maybe but isn't the duration low for a SB? I don't know.
I played with it for a while and found it to be weird.
#10
Racer
Alot of these ideas I have looked into for a performance improvement on my 1980. My problems seem to come from the fact that I do not want to alter the stock hood on my car. I know that I looked into alot of different combinations but always came up with hood clearance problems. I really like the look of the stock hood and will not modify it . Brent
#11
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St. Jude Donor '07
It's alot harder than people think. I'm not calling anybody out, but when most people dyno their combo 400 hp turns into 250 hp. I would try one of those package deals and add highier compression pistons. Compression = HP
#12
Le Mans Master
Originally Posted by Corey_68
Having a friendly discussion in which I stated a decent duration cam, intake, and headers would net 350hp. I was told "No way", not I relaize the compression was 8:2 maybe if the heads were shaved one thousandth, and a thinner gasket installed to raise compression might do it?
So you L48 owners, what did/does it take to make 350-400hp??
So you L48 owners, what did/does it take to make 350-400hp??
-Mark.
#13
Originally Posted by Corey_68
Having a friendly discussion in which I stated a decent duration cam, intake, and headers would net 350hp. I was told "No way", not I relaize the compression was 8:2 maybe if the heads were shaved one thousandth, and a thinner gasket installed to raise compression might do it?
So you L48 owners, what did/does it take to make 350-400hp??
So you L48 owners, what did/does it take to make 350-400hp??
P.S. We weren't specifically chasing HP on this engine, we built it totally for longevity. It did have all top-notch internals however. A slightly different cam grind could have produced more power, but the cam in this engine was strictly a customer choice.
#15
Drifting
Originally Posted by Corey_68
Having a friendly discussion in which I stated a decent duration cam, intake, and headers would net 350hp. I was told "No way", not I relaize the compression was 8:2 maybe if the heads were shaved one thousandth, and a thinner gasket installed to raise compression might do it?
So you L48 owners, what did/does it take to make 350-400hp??
So you L48 owners, what did/does it take to make 350-400hp??
BigBlockk
Later.....
#16
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St. Jude Donor '07
Originally Posted by Budman78
It's alot harder than people think. I'm not calling anybody out, but when most people dyno their combo 400 hp turns into 250 hp. I would try one of those package deals and add highier compression pistons. Compression = HP
Last edited by yellow73sb; 08-14-2005 at 11:13 AM.
#17
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St. Jude Donor '07
Originally Posted by BigBlockk
A blow through turbocharger.
BigBlockk
Later.....
BigBlockk
Later.....
#18
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L82 cam is a good cam for mild performance.
Originally Posted by GOSFAST
...The factory cores including heads, intake, and original cast iron exhaust manifolds. We used Ross L/W pistons and the factory L-82 cam. We tested it with 2 different carbs just for comparison purposes. First test was with 650 Holley with stock alloy intake (for Holley, not for car), then with customer's own intake and Q-jet. HP and torque numbers were almost identical. We made 355+ HP @5800 and 385 Ft.Lbs. @ 4100. This was through his stock exhaust manifolds.....
IMHO 1hp per c.i. is very easy to do for the least amount of dollars. Even with stock wheezer heads some simple pocket porting and thinner hd gasket for little more c.r. and a lot better quench should get u there still using just stock junk pistons. Other little tricks help too like if u can't install screw-in studs then at least pin in the rocker studs. While heads are off why not elongate the slots for 1.6 rockers too? 3 angle vlv job is cheap while heads off and why not 4 or 5 angle if u can find the right shop?
Ok i'll shut up but just my 2 cents here. cardo0
#19
Melting Slicks
Originally Posted by Corey_68
Having a friendly discussion in which I stated a decent duration cam, intake, and headers would net 350hp. I was told "No way", not I relaize the compression was 8:2 maybe if the heads were shaved one thousandth, and a thinner gasket installed to raise compression might do it?
So you L48 owners, what did/does it take to make 350-400hp??
So you L48 owners, what did/does it take to make 350-400hp??
#20
Melting Slicks
Originally Posted by yellow73sb
Flat tops with 64cc chambers arent gonna be 10:1.
Originally Posted by glen242
Milling your heads down to 64cc, using a 6 cc for the pistons, 0.039 gasket, and stock +/- 0.025 in the hole, you get 9.6 CR. You do the math. Don't forget quench.