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L-48 Cam Upgrade

  • Thread starter Thread starter Spdfrk
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Spdfrk

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Ok guys here's another question. We have the L-48 engine to install into our resto but I was thinking, seeing as its already out how about doing some work to it. Here are the mods that I can see on it. I doubt that the internals were changed. It has 46000 original miles on it.

Hooker headers
Dual exhausts (no cats!!)
Edelbrock Performer Manifold
Holly 600 cfm 4 barrel Carb
HEI upgrade

Now I was thinking of putting in an upgraded Cam. But what type should I get?? I want good performance and a real nice lopy idle, fit for a Corvette!!. Any suggestions??
 
Spdfrk said:
Hooker headers
Dual exhausts (no cats!!)
Edelbrock Performer Manifold
Holly 600 cfm 4 barrel Carb
HEI upgrade

Any suggestions??

With those mods ... I'd wonder if the cam may've also been upgraded? It may be worth the time & trouble to pull a valve cover and put a dial indicator on a couple valves ... get an idea if the cam may've been swapped. BTW ... OE lift at valve for L48 about .390" intake & .410" exhaust.
JACK:gap
 
How come there's only a 600 cfm carb in there? I think stock is a 750 cfm, right? And how did you get away with no cats? With a '77 don't you have to pass emissions? :confused

TR
 
Stallion said:
How come there's only a 600 cfm carb in there? I think stock is a 750 cfm, right? And how did you get away with no cats? With a '77 don't you have to pass emissions? :confused

TR
I believe it has to do the regulations of the state that your in. My 77 was required to only pass a mechanical inspection and not a sniff test because it was over 25 yrs. old according to the mechanic where I had it inspected.

:v
 
The L-82 cam is an inexpensive upgrade, and uses all stock GM reliable/proven valvetrain parts; all you need is the cam and lifters - uses the stock pushrods/rockers/springs you already have.
:beer
 
C3forME said:
I believe it has to do the regulations of the state that your in. My 77 was required to only pass a mechanical inspection and not a sniff test because it was over 25 yrs. old according to the mechanic where I had it inspected.

:v

Oh, okay. I think NJ is pretty strict. I have to pass emissions. :(

Otherwise I would take the cats off too and put on a true dual. :)
 
Cam selection can be such a tricky thing. Without knowing exactly what else has been done to the engine, it can be difficult to come up with a combination that really works well. If the L-48 is basically stock, the compression ratio will not support a cam with a 'lopey idle'. The lope comes from valve overlap, which lowers your dynamic compression ratio. It sounds really cool when it is idling, but unless you have sufficient static compression, your low end performance is going to be really disappointing and you will have trouble getting out of your own way.

There are other considerations, such as gear ratio, stall converter, etc. But be aware, that 'seat of the pants' thrill that we all seek in these things is created by torque. A cam that makes good torque from 1000 RPM on up to 4500 will make you very happy.

I want to make sure that I don't upset anyone here, so I will add the proviso that this is just my opinion . . . from someone who's been there done dat . . .

Ron
 
I have the stock carb, how many barrels are in her? Just 2 I assume?

Thanks! :D

TR
 
Perfect. Thanks for all your reply's I will take them all into account. As for Smog regulations here, there are none!!! Its bad I know but on the other hand it plays in my favor.
We dont abuse it though.
 
L82 Cam is an excellent upgrade though with automatic it will like a higher stall converter. 600 Holley should be traded for a proper QJet which is a much better carb.
 
SpdFrk - It's not BAD - it's FREEDOM!

Don't let these PC "anti-drivists" make you feel their snake oil regulations are "enlightened." Most of what was agreed on was done so corruptly and undemocratically in backrooms away from voter reveiw that it made normal legislation look clean. They often pull a "bait and switch" and swap one body of regs for what they originally barely got support for passage for, all with the corrupt, biased press cheering them on. It was often - and still is - the shakiest of science too.

In some places like Texas, these arbitrary standards, which exempt government run operations polluting hugely have made owning a performance car more than a couple of years old but less than the 25 year old cut-off, registered in the larger population areas highely problematical. I have passed up some very nice ones because the "safety" inspection would probably never be meetable unless I start breaking laws and bribing people.

Take a look at acid rain and catalytic converters. Direct relation? You bet. To get rid of some unburnt hydrocarbons and carbon monoxide we convert lower nitrogen oxides to higher, more acidic ones. To fix a localized urban problem, we increase considerably the load of acid we dump in the rural areas. Some "earth lovers."

We could have lowered pollution output at the tailpipe and even much more at the refinery all these years with alcoholized fuel blends. I would love to burn some nice 20% gasahol or gasohol with 100+ octane for $1.10 a gallon. The sanctimonious "greenies" get furious at "children starving for your damned cars!" and the oil companies breath a sigh of relief at their industry not being compromised by agriculture. Other than some solid wastes from regular and destructive distillation, fuel mixed-alcohol production is perfectly clean, especially compared to petroleum refining and shipping, and oxygenated fuels are already required some times of the year in many areas. Apparantely our agricultural waste products are destined to feed children though.

As far as these silly, arbitrary, undemocratic pollution regs go, be happy you don't live in the once free USA. :( :pat

By the way, I took a 600 Holley off of mine when I got it because the back barrels weren't getting fuel to them. (I also prefer the easy changeability of the AFB design, but I'm no carb tuner.) I've already promised the clogged thing to a friend though. Sorry! :(

TR:
I don't believe any of them came with 2-bbl carbs. It's possible, but I don't think so.

Hey - don't be so sure about NJ's regs. Call your State Trooper office or State Environmental Agency and ask what cars are subject to pollution inspections. Some may also be performance based and may allow alterations if equivalent equipment is present and it functions as well as the original. (Thus true duals with two performance cats could be OK, if they are even required.)
 
Spdfrk

For cam you need to state trans. & gears.



Stallion

Stock is 4 barrel Q-J.
600 Holley is all that's needed for a mild 350.

Suggest Increase Power!

:cool
 
I'm not happy with the 'tree hugger' crowd either - plus I'm a gun owner and big game hunter. But, is this the correct forum to air those grievances?
 
Sorry about that - I don't usually mix interests

I just couldn't stand our friend from the West Indies apologizing for his country having not enacted such stupidity.

I apologize if I caused any offense, and in general I try not to initiate a side commentary, but I certainly wasn't going to let stand someone feeling they were doing something wrong in enjoying more freedom than we do. That's allowing the Greenies to have free say! (Not while my antiquated, wasteful butt can waste their O2!)

Being in an environmental industry - a sewage worker - I actually am quite pro-environmental, but not for every watered down or incorrect notion of useful environmental legislation ever proposed and passed just because it said it was "for the Earth" or from people who had proposed good, useful things before.

I only mentioned my arms rights/gun control position in one or two previous posts, despite being an extreme activist and having devoted eight years and over $60,000 to that pursuit.
 
L-48 cam upgrade

one option you may look at is...... depending on use would be to go with an L-82 cam and heads, a little lope, and air conditioning. the inspections are not very restrictive here either. L-48 true duals, no cats not against the law on an antique.
 

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