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Old 03-08-2010, 10:30 PM   #1
hkdcamcain
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Default L48... Power Boost?

In the processes of gathering and rebuilding the engine and car currently, but judging by the various bits of info i can get the L48 is not what i would call a "performance" engine... im looking to get the horses up a decent bit?
I am already getting Hooker Side exhausts with high flow piping... let me know the basic things i can do? and rough costs of each? thanks

Note: im hoping for about 250 hp in the end... not tonnnsss but a decent bit
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Old 03-08-2010, 11:42 PM   #2
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You would probably be better off rebuilding the entire engine. However, if your L48 is in decent condition and you're only looking for about 60 more hp, then a new aluminum intake, aluminum 64cc heads and a better cam with a little more lift and duration, with headers, will easily get you there. Check out the Summit Racing catalog for parts like Edelbrock. Probably about $1650 for the above with new gaskets and fasteners. Good luck with your project.
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Old 03-09-2010, 12:03 AM   #3
glen242
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Heads and cam is where you need to go.

My L-48 ran well with a set of TF 64cc heads and a CC268H cam. This was with true duals and a 4-speed.

I am now running those same heads on my 383.
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Old 03-09-2010, 12:25 AM   #4
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hey, i did a complete rebuild, and modified the block.

With 250 horse that can be done easy with some affordable heads and a mild cam. you can save yourself a lot of money by buying rebuilt heads, honestly i wouldn't worry about a fancy intake or aluminum heads. Replace your Q jet (if it needs to be rebuilt) with a Holly or Ebrock whatever your choice either will work. You can easily get 60 horsepower from heads (either modify the factory heads or get some rebuilt ones) and a cam swap.

This engine started out life as a L48. (it snowballed into this)
Click the image to open in full size.

Click the image to open in full size.
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Old 03-09-2010, 08:38 AM   #5
7T3C3TTZ07
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Quote:
Originally Posted by hkdcamcain View Post
In the processes of gathering and rebuilding the engine and car currently, but judging by the various bits of info i can get the L48 is not what i would call a "performance" engine... im looking to get the horses up a decent bit?
I am already getting Hooker Side exhausts with high flow piping... let me know the basic things i can do? and rough costs of each? thanks

Note: im hoping for about 250 hp in the end... not tonnnsss but a decent bit
SStocker31 had posted earlier that a low-cost upgrade to L48 is to install iron Vortecs (PN:12558060 from junk yard) with rubber-coated thin steel shim head gasket Felpro p/n Z1094. Static compression ratio will be just shy of 9.5:1. Cam swap Summit's K1103 cam & lifter kit. Z28-type springs, Edelbrock 2116 Vortec Performer and new timing chain. He estimated all this for under $750. SStocker31 did not estimate the HP for this. It may be close to the 250 mark.
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Old 03-09-2010, 09:47 AM   #6
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Heads, cam and exhaust are the places to start. If your Q-jet is still in good shape, keep it...it's already capable of 750cfm; your present set up just doesn't use much of it. Intake is a good idea, if you change out the heads; keep it 'as is' if you don't.
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Old 03-09-2010, 10:02 AM   #8
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Thanks to the op for starting this thread and also those responding, saves me time from posting and searching myself :p
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Old 03-09-2010, 02:28 PM   #9
hkdcamcain
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Default Ok quick q update

Engine looks a little rough currently, but my grandfather and I would like to keep the stock engine, so we are looking into it a little more, and having it completely repaired by an uncle who rebuilds muscle cars, such as his White Lightning and such that has made it onto pinks all out. But a problem... with enough effort, will this engine be able to run really fast? i mean in the long run... i just dont want to put effort into the L48 just to turn around and have to engine swap later for power... currently its going to be a drive around car around 250 hp when finished, but i would like to add alot more if possible down the road, so for long term what would i be looking at as a rough estimate for how much power i could get out of it?
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Old 03-09-2010, 03:37 PM   #10
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250 HP (you didn't specify flex-plate or rear-wheel HP) from an L-48 shouldn't be hard at-all... based-on weight-to ET & MPH (3600 pounds, 14-flat @ 97 MPH), my de-Cross Fire'd '82 makes 230+ RWHP, and showed 238 on a chassis dyno:
here you will see a 3 year-old piece, where a nothing-special 290 HP crate-motor actually made 310+ on a dyno, then was transformed into a 380+ HP terror, on readily-available pump-gas

http://www.chevyhiperformance.com/te...ine/index.html

about that same time, a friend of mine needed to replace the OEM cam on his '80 L-48 that had wiped-out a lobe ~ although he has since sold the car, here is his story

http://forums.corvetteforum.com/c3-t...clearence.html

the ability to 'run really fast' (i.e.- at the strip) will depend upon other factors, like gearing, traction, and an overall combination
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14-ohs @ 95+ MPH, best-of 13.935 @ 99.14

GONE 7 FEBRUARY 2012, BUT NOT-FORGOTTEN
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Old 03-09-2010, 03:46 PM   #11
hkdcamcain
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i have no desire to have a "Beast" of an engine currently, due to the fact this car is a gift for me and my grandpa to work on as a family thing, but eventualy i was going to try and get the most i could out of it, I.E. new cams, heads, headers, valves, etc etc etc... was wondering how much i could pull out of it in the end, also how rough would a supercharger be on it?
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Old 03-09-2010, 03:56 PM   #12
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Plenty of fast Chevys have been built w/ those engines. Supercharger no problem.
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Old 03-09-2010, 03:59 PM   #13
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My goal is to have something that can stand up to the current corvettes, maybe not as fast but close... considering my primary car is a 02 Toyota Celica GT-S running 190 to the wheels, (cold air intake, header, exhaust, heads, higher compression...) i would like for my project car to be faster than my daily driver....
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Old 03-09-2010, 05:46 PM   #14
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Current Corvette have a lot more HP than that. I think 330 hp is the smallest engine on the list. And, with they're wide rear tires, they can put it all to the ground. To get 330 hp out of your 350 ci engine, you will need, heads, cam, better flowing intake, and exhaust system. Now, if you just want to "pump it up" a little bit, optimize the distributor advance timing curve, re-jet the Q-jet, and stick a more potent roller-lifter cam in your engine. It will 'perk up' what you have now.
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Old 03-09-2010, 07:11 PM   #15
hkdcamcain
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Quote:
Originally Posted by 7T1vette View Post
Current Corvette have a lot more HP than that. I think 330 hp is the smallest engine on the list. And, with they're wide rear tires, they can put it all to the ground. To get 330 hp out of your 350 ci engine, you will need, heads, cam, better flowing intake, and exhaust system. Now, if you just want to "pump it up" a little bit, optimize the distributor advance timing curve, re-jet the Q-jet, and stick a more potent roller-lifter cam in your engine. It will 'perk up' what you have now.
Ok well i already have a new Exhaust, its a hooker header to side exhaust system, and im planning to get some more agressive cams, and polishing the replacement heads, and an aluminum intake, how much should that add to the car?
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Old 03-09-2010, 07:11 PM
 
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