In the 73 SPOT I noticed an article which is interesting.

The testers really liked the L48 base engine as they said performance difference wan't that great between the L48 and the L82.
They noted the L48 ran smoother and cooler.
The L82 idled rough and was only mariginally faster in the quarter mile and it had a higher gear ratio!

This was in
MAG-ELLE-O-MANIA, High Performance Cars, September 1973

Anyone out there had a 73 L82 and a 73 L48 and noticed major difference?..because sometimes SOTP can be a factor in engine characteristics.

 

 

L-82's were a better built engine,4 bolt mains, steel cranks, windage trays, higher CR, better cam,better heads. L-48's are very good driver motors but if you have a choice, pick the L-82.
Gary

 

I have had both. The L-82 is quicker if you keep the rpm's up. The L-48 is a good cruise engine poor acceleration when at speed. The L-82 engine is happiest at 2500 rpm and above. Around town and the L-82 in second gear and the acceleration was great, accelerating at 60 mph you know when the engine hits 2500 rpm.
Get the L-82.
Roger

 

I thought so... The L82 has to be faster. This mag shows a 0-60MPH of 6.8 for the L48 and 6.7 for the L82 and the quarter like .1 off!!

So I know different mags had different times but this one raised my eyebrow. LOL

Good to know.. I have to put either my 454 or build a 383 stoker for my car.I want to keep the matching numbers engine which runs great intactand not kill it. LOL

 

L82 also had peened, fluxed rods and I think pushrod guides.

L48s go back to '69 or '70 on Corvettes as the base engine - there are slight differences from year to year w/ both engines. W/ a rebuild the whole question often becomes more academic than anything else. Today there are better cams than either the L82 or L48 stock cam for example. Simply saying the L82 cam is 'better' ignores the fact that the L48 cam produces more torque at a lower RPM - which for some folks is more important.

 

L-48 is the same engine used in a station wagon. All the good parts go into the L-82. Stronger parts as well as faster. The RPM range is higher too. You do not notice much difference untill you ask more of it. Pull the original cat off them both and the difference will be even greater.

-Mark.

 

It doesn't take a whole lot of parts swapping to wake up either of these motors. Especially in a jurisdiction where smog control is not an issue on older cars.

 

I know by swapping parts I can increase power on my base L48, and it would run strong.. I think I'd rather yank it..put it aside and drop in either a stoker 383 or go maybe.. Big Block 454?

I have the 454 already with rect port heads and the LS6 Low rise dual plane manifold. (hard to find item) or go with a light weight small block?

I'll decide for the next couple of months, because when April hits. I'm itching for a project to bestow between my Vettes fenders. LOL

Any suggestions? I was thinking the stroker 383.

 

As I said before, L48s were base engines in Corvettes since 1969. Just an FYI but there were no catalytic converters installed on (dual exhaust) L48 equipped Corvettes between 1969 and 1974 making the suggestion above somewhat difficult. In some years the L48 shared it's head castings w/ LT1s and L46s (L82 predecessor). The Corvette L48 also sometimes received other HD parts shared only with HD trucks.

L48s were optional engines in Camaros, Chevelles, Novas and a few others. However L48s in Corvettes had different carburetion calibration, air cleaner and exhaust and possibly different ignition advance curve map.

Mark - which models/years Chevrolet station wagons were the L48s available in?

 

Are we going to pick apart the engine to determine the part numbers of the rod bolts? There are a few hairs to split but why?

Station wagon engine is not far from the truth from a functionality standpoint. They both use the same "929" cam, they both use the same connecting rods, the same cast aluminum dished pistons, the same cylinder head castings with the same small valves, no chamber unshrouding, the same engine case (block), the same cast iron crankshafts, the same small balancers, and the same shallow groove pulleys. There are differences in the intakes mostly because of the hood on the Vette being so low that it needs to be shorter than the intakes used on other cars. The carbs and distributors are calibrated differently but not because they wanted the Station wagon to be slower but because they are different in application only. Maybe the L-48 got the truck timing gear setup but who knows? That would not be a big difference here. For any year after 74 they both had cats.

LT-1 for a '70 Vette is different from the LT-1 in a '70 Camaro but not by much.

True, they do not have the same engine suffix code. If they did, they would be exactly the same assembly. Even so, these are both functionaly equivalent in terms of strength and hot rod potential.

-Mark.

 

great point !

 

I have a '73 L-48, automatic coupe. I installed a Comp Cam H268 & had a 3 angle valve job done to the stock heads (this was a very budget restricted build). I used the stock intake along with the original Q-jet, which received a "rebuild" by a local "Q-jet guru" (he ain't Lars, but he's darn good.). I had the original ditsributor rebuilt by a friend who used his Sun diagnostic machine to set it up. The only other mod to the engine was a set of headers. We installed a B&M street/strip shift kit in the otherwise stock TH350. I also swapped out the original 3:08s for a set of 3:70s. Talk about waking up the L-48! Ton of torque and bottom end and it will flat plant you back in the seat when it shifts with the shift kit and 3:70s. Granted the L-48 doesnt have the "tougher" internal bottom end but my point being that the L-48 can be turned into a nice little street motor without spending mega bucks. I suspect that a set of Vortec heads, along with a suitable intake would really wake the little motor up that much more. JMHO

 

During some model years (i.e. 1977), the L-48 produced slightly more torque than the L-82 (270 lbs/ft vs. 255)

 

First...

Then...

Perhaps a little exageration for effect?


The same as the 'not-far-from-truth' station wagon?

THe L82 rods, as I said before, come from the same pile - but they are of course fluxed/peened.

Uh no, not all L48s got dished pistons. Nor were dished pistons exclusive to L48s. You may be surprised to find some dished pistons a little 'closer to home'. Some L48s have higher CRs than L82s. Arguably some folks feel the forged pistons may be a liability due to potential piston slap in the long term.

I'd like to hear more about this 'high rise station wagon intake' - maybe it would be a low cost higher rpm HP improvement over the stock low-riser spread bore intake for L48 owners w/ modified hoods...?

Perhaps you should have presented the differences in balancers in the same light as above - they are not about 'size' but about a specific RPM range in which they operate based on crank harmonics at certain RPMs.

Why dismiss a HD part just because it may have been shared by another platform like a truck? One could probably sit here and if not jaded by reading too many magazine articles w/ prolific advertisements, say the same thing about your precious pushrod guides too.

Just what are we supposed to look for that proves anything when we 'look' at the cats on an L48 as you previously suggested?


The overwhelming majority of all LT1s, L46s, L82s and, yep, even L48s got '010' block castings.

Mark, I think the information you have presented on L48s and L82s is A) simplistically dismissive, B) overly generalized and C) does not recognize the tradeoffs between high RPM HP and low RPM torque. Each has merits with notable trade-offs and each should be considered as a whole package, it's intended usage and year by year differences.