L-48 Engine
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Pretty much a slug motor.
There was 2 engines offered in 76. The L48 which is the stock low performance motor. The same motor used in passenger cars also. The L82 was the high performance motor. It had forged internals and more HP but it was no barnstormer either. The L48 can be made to have some power but it takes some work and money.
There was 2 engines offered in 76. The L48 which is the stock low performance motor. The same motor used in passenger cars also. The L82 was the high performance motor. It had forged internals and more HP but it was no barnstormer either. The L48 can be made to have some power but it takes some work and money.
Last edited by Gordonm; Oct 28, 2004 at 06:37 PM.
Race Director
Joined: Apr 2000
Posts: 17,648
Likes: 189
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
You need new heads, steel shim head gasket to get the compression up, aftermarket intake, Holley carb ( my preference ). Then you need headers 2 1/2 in., exhaust and a new cam ( CC 270 Magnum is a good start ) Pull alll the smog stuff off and your set 
If you don't do that prepare to get smoked by every ricer that pulls up beside you at the lights ( drag strip lights of course )
If you don't do that prepare to get smoked by every ricer that pulls up beside you at the lights ( drag strip lights of course )
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
The L48 is really not the greatest... if you're looking for performance you will probably not like either one (L48 or L82). The necessary modifications are basically the same: heads, cam, intake and carb. headers are a good idea but can be done later as it is external ....
the L48 runs strong with these mods but be aware that your crank is the weak link.
the L48 runs strong with these mods but be aware that your crank is the weak link.
Thread Starter
Instructor
Joined: Oct 2004
Posts: 208
Likes: 0
From: Cumberland RI
Hey guys thanks for the info, If I go for it ( which I most likely will) at least I got an idea as to what I need to do. I wonder if headers are ok to use in Rhode Island, I will have to look into that.
Instructor
Joined: May 2004
Posts: 183
Likes: 0
From: Lower Burrell PA
RedBad1979, I have an L48 in a 77 with 55,000 miles. I was planning on changing cam, installing vortec heads and intake and carb with headers. THe vortec heads with 64cc chambers will take the motor to about 9.5 to 1. Do you think I am asking for trouble, the bottom end seems fine, I will plastic gauges the bearing when it is apart? While I am doing this just spend another $1,200 and buy a 4 bolt long block? Your thoughts?
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Originally Posted by finallygot1
RedBad1979, I have an L48 in a 77 with 55,000 miles. I was planning on changing cam, installing vortec heads and intake and carb with headers. THe vortec heads with 64cc chambers will take the motor to about 9.5 to 1. Do you think I am asking for trouble, the bottom end seems fine, I will plastic gauges the bearing when it is apart? While I am doing this just spend another $1,200 and buy a 4 bolt long block? Your thoughts?
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Instructor
Joined: May 2004
Posts: 183
Likes: 0
From: Lower Burrell PA
Gordonm, any suggestions on what I am planning on doing? It will not be drag raced, it will be driven probably 2,000 mile per year. Don't wanna put a whole bunch of money in the car, the heads we're given to me. Was planning on having them redone, screw in studs put in and have them cut to take a cam larger than the .480 lift that the stock head can handle. Suggestions would be appreaciated. cam suggestions?
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
[QUOTE=MotorHead]You need new heads, steel shim head gasket to get the compression up, aftermarket intake, Holley carb ( my preference ). Then you need headers 2 1/2 in., exhaust and a new cam ( CC 270 Magnum is a good start ) Pull alll the smog stuff off and your set
Doing the aforementioned mods will not only bump the horsepower but will make it as potent, if not more powerful, then most C3 small block vettes that Chevy produced. Today's perforance heads are much better than the old designed double humps. Headers will add 15hp or so. The cast crank can easily withstand 400hp with out problems.
Doing the aforementioned mods will not only bump the horsepower but will make it as potent, if not more powerful, then most C3 small block vettes that Chevy produced. Today's perforance heads are much better than the old designed double humps. Headers will add 15hp or so. The cast crank can easily withstand 400hp with out problems.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by Gordonm
Pretty much a slug motor.....
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by finallygot1
Was planning on having them redone, screw in studs put in and have them cut to take a cam larger than the .480 lift that the stock head can handle. Suggestions would be appreaciated. cam suggestions?
Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining. It allow using the factory valve seals as well.
I have a set of Vortec's and may switch to this setup prior to assembly.
Here is some add'l info: http://www.sallee-chevrolet.com/Cyli...ds/Vortec.html
Race Director
Joined: Apr 2000
Posts: 17,648
Likes: 189
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Actually I know a forum member ( desi ) who is doing everything I just mentioned with my Sportsman II heads, he will have it dynoed in the spring I'm betting over 275HP at the rear wheels which is in the same neighbourhood as a stock C5
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
Have an L48 in my 80... Now putting out 320hp at the crank.
Mods:
Edelbrock RPM 64cc heads (ported and polished)
Edelbrock Performer intake
Edelbrock Thunder AVS 650
Flame Thrower HEI
XE274 Cam
Roller Rockers
Hooker Headers
True Duals
Flowmaster Delta 40s
Mods:
Edelbrock RPM 64cc heads (ported and polished)
Edelbrock Performer intake
Edelbrock Thunder AVS 650
Flame Thrower HEI
XE274 Cam
Roller Rockers
Hooker Headers
True Duals
Flowmaster Delta 40s
Melting Slicks
Joined: Dec 2000
Posts: 2,198
Likes: 2
From: Eastern Connecticut
Originally Posted by mandm1200
There is no need to have machine work done to the heads in order for them to use a cam with greater than .480 lift. Crane has a kit, springs and retainers, that will allow lift up to .550".
Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining. It allow using the factory valve seals as well.
I have a set of Vortec's and may switch to this setup prior to assembly.
Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining. It allow using the factory valve seals as well.
I have a set of Vortec's and may switch to this setup prior to assembly.
Jegs price:
270-10309-1 Spring & Retainer Kit $153.99
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
Originally Posted by finallygot1
RedBad1979, I have an L48 in a 77 with 55,000 miles. I was planning on changing cam, installing vortec heads and intake and carb with headers. THe vortec heads with 64cc chambers will take the motor to about 9.5 to 1. Do you think I am asking for trouble, the bottom end seems fine, I will plastic gauges the bearing when it is apart? While I am doing this just spend another $1,200 and buy a 4 bolt long block? Your thoughts?
I am planning on installing a forged crank, good rods and forged pistons next year. My bottom end is still good and I don't drive very slow...
If you're planning on taking the engine out anyway then go with a stroker kit and get the block machined ... I regret that I haven't done it when the car was apart.
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by joe73vette
Wow, you had me interested there, but when I saw the price I realized getting the high lift heads from Scoggin-Dickey would be the same price as the standard heads plus this kit. I guess if you already have the heads it's a good alternative. Joe
Jegs price:
270-10309-1 Spring & Retainer Kit $153.99
Jegs price:
270-10309-1 Spring & Retainer Kit $153.99
I'm not sure what Scoggin-Dickey or Pace charge for upgrading the Vortec heads (too lazy and busy at the moment). I was also dissapointed when I saw the price of the Crane kit. Either way adds cost and takes away from the perf vs. value they offer.
Instructor
Joined: May 2004
Posts: 183
Likes: 0
From: Lower Burrell PA
Originally Posted by mandm1200
There is no need to have machine work done to the heads in order for them to use a cam with greater than .480 lift. Crane has a kit, springs and retainers, that will allow lift up to .550".
Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining. It allow using the factory valve seals as well.
I have a set of Vortec's and may switch to this setup prior to assembly.
Here is some add'l info: http://www.sallee-chevrolet.com/Cyli...ds/Vortec.html
Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining. It allow using the factory valve seals as well.
I have a set of Vortec's and may switch to this setup prior to assembly.
Here is some add'l info: http://www.sallee-chevrolet.com/Cyli...ds/Vortec.html
http://www.automotiverebuilder.com/ar/ar99928.htm
I have attached an article on the LT1/LT4 and under head gasket section it explains that the heads are not interchangable
http://www.jegs.com/cgi-bin/ncommerc...26&prmenbr=361
Jegs shows the part # for these springs and the application as LT-1 iron heads. I just don't want to see anyone destroy a motor. I think the price to have a used set machined, 3/8" screw in studs and machined for the larger lift is around $350 at a local machine shop. Any article you read will tell you you have a great deal in these heads. My 2cents worth.......
