L48 vs. L82
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Short answer, no, not really, heads, cam, pistons, and some say also the block is 4 bolt mains for the L82.....
which will not mean much for hotrodding for street use....
in fact the late 70's heads are rather poor no matter which engine....thin castings....lo flow rates, which suited the mild cams, but limit performance....then there are the cat *** trophic converter requirements, and single exhaust...the list is long, and the cures vary wildly depending on your local .gov inspections....
which will not mean much for hotrodding for street use....
in fact the late 70's heads are rather poor no matter which engine....thin castings....lo flow rates, which suited the mild cams, but limit performance....then there are the cat *** trophic converter requirements, and single exhaust...the list is long, and the cures vary wildly depending on your local .gov inspections....
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Yes it can be done but as the previous poster mentioned,you would have to get better flowing heads. The L82 cam is the same as the L46 engine. Pistons in the L82 engine are forged with a single trough relief.
Le Mans Master
Joined: Apr 2005
Posts: 6,339
Likes: 416
From: Seattle Area WA
Not only are the pistons forged but so is the crank for a stronger bottom end. Basically if you want to swap heads, cam and intake you can make a very good running L-48 assuming that the short block is in good condition.
Pro
Joined: Nov 2002
Posts: 599
Likes: 16
From: vista CA
Pro
Joined: Jul 2005
Posts: 517
Likes: 7
From: Peoria IL
The Vortec head swap is very popular, and will nearly double the original L48 power output with the right intake, camshaft, headers, and dual exhaust. 360hp is well within reach, forget about 220hp.
Racer
Joined: Mar 2006
Posts: 349
Likes: 0
my buddies motor in his camaro is 2 bolt, with 600 hp, i wouldn't do it, but its holding up just fine.
Thread Starter
Intermediate
Joined: Sep 2008
Posts: 41
Likes: 0
From: Shelton WA
well the reason i want to keep the L48 cuz its matching number.. but i'm thinking against that now and if i can just find a 427 or 502 that my friends dad gets rid of all the time(he does super comp drag racing)
kk now my question is can i put a 427 or 502 in a 1978 L48 vette?
i'm guessing that its easily possible.
kk now my question is can i put a 427 or 502 in a 1978 L48 vette?
i'm guessing that its easily possible.
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Pro
Joined: Jul 2005
Posts: 517
Likes: 7
From: Peoria IL
Sure, the chassis was designed to accept big blocks and little was changed between the early 70's and your 78. There is a wealth of information on this forum about the details, but the motor mounts will simply bolt up. You'll have to work through details like alternator and power steering brackets, A/C compressor brackets (if you intend to keep/install it), and the radiator fan shroud. Hood clearance will need careful attention too.
Don't put an abused, tired engine in your car...you'll just be asking for trouble.
Pro
Joined: Jul 2005
Posts: 517
Likes: 7
From: Peoria IL
That's one good reason for being 'done' with it, but others are: changes in rules, different car, wanting to compete in different class, wants new/bigger flavor-of-the-month engine, etc...
I bought a 396 from a buddy that was "done" with it in his T-bucket. He wanted a 454. There was no sensible reason for it, he just wanted it. I bought another one from a different friend that sold the car but the new owner wanted only a roller.
Give the guy a break, there are a wealth of reasons why a engine may retired from a particular application but be perfectly suitable for a street car/play toy for many years in the future. At the least, it may be a perfectly suitable core for a rebuild project (if that's Dacksoldier's intent).
EDIT: Dacksoldier should certainly be aware that the engine might be tired/worn out, but if this guy is truly a friend he should be pretty well informed about the situation and have some idea about the condition of the engine.
Last edited by dstaley; Sep 11, 2008 at 12:22 PM. Reason: Added additional comment
Pro
Joined: Nov 2002
Posts: 599
Likes: 16
From: vista CA
well the reason i want to keep the L48 cuz its matching number.. but i'm thinking against that now and if i can just find a 427 or 502 that my friends dad gets rid of all the time(he does super comp drag racing)
kk now my question is can i put a 427 or 502 in a 1978 L48 vette?
i'm guessing that its easily possible.
kk now my question is can i put a 427 or 502 in a 1978 L48 vette?
i'm guessing that its easily possible.
A few years ago I wanted more power from my stock L48 1979 - ended up putting in an LS1 and T56 and have never regretted it. I was on the fence though to just keep my L48 block and rebuild with crank, rods, pistons, cam, heads (would've been less expensive and not taken as long)....not entired sure why, but still have the numbers matching L48 and TH350 in the shed (seriuosly doubt they will ever get back in their original home)
Melting Slicks
Joined: Apr 2008
Posts: 2,621
Likes: 242
From: Russell Ontario
St. Jude Donor '09
All I did was swapped Cam ,intake, true dual exhaust, recurved distributor, on my L-48 and on the dyno I pulled 221 hp at the wheels .This was cheap and quick to do , and cheap too! Ron
Le Mans Master
Joined: Apr 2005
Posts: 6,339
Likes: 416
From: Seattle Area WA
68Firebird,
Regarding your plan for the XE-262 cam and keeping your existing valve springs. You will need to call Pioneer and verify the spring rate with them, but I will venture to say that you will need to run the Comp Cams matching springs. Pioneer calls the RV-943-4 a .490" Z-28 spring and I do not see a spring rate for them. The Comp XE Cams require the use of a pretty stout spring due to their fast ramp rates. These are Comp 981-16 which are rated at 370 pounds/inch. The GM Z-28 and off-road springs are around the 300-325 pounds/inch rate.
Regarding your plan for the XE-262 cam and keeping your existing valve springs. You will need to call Pioneer and verify the spring rate with them, but I will venture to say that you will need to run the Comp Cams matching springs. Pioneer calls the RV-943-4 a .490" Z-28 spring and I do not see a spring rate for them. The Comp XE Cams require the use of a pretty stout spring due to their fast ramp rates. These are Comp 981-16 which are rated at 370 pounds/inch. The GM Z-28 and off-road springs are around the 300-325 pounds/inch rate.
Instructor
Joined: Dec 2007
Posts: 246
Likes: 2
From: colonia New jeresy
I have a 73 L-82 it has a steel crank/x rods/forged flat top 2 valve releif pistons /4 bolt block 6 qt oil pan trap door/windage tray and the cam is the 350 350 hp . head are 202 valves /guild plates/screw in studs. basically its a lt1 with less compression and a hydraulic cam. its a #matching car. but yes you can make the same or more power no problem. hope this helps
Pro
Joined: Jul 2005
Posts: 517
Likes: 7
From: Peoria IL
I have a 73 L-82 it has a steel crank/x rods/forged flat top 2 valve releif pistons /4 bolt block 6 qt oil pan trap door/windage tray and the cam is the 350 350 hp . head are 202 valves /guild plates/screw in studs. basically its a lt1 with less compression and a hydraulic cam. its a #matching car. but yes you can make the same or more power no problem. hope this helps