MORE MUSCLE

[KarlosM]

I have a 77 with an L48 engine, 3.08 axle ratio, quad carb, and auto trans. Everything on the car is stock and original with the exception of the battery, tires and the exhaust. Original owner (family) with very low mileage 41,000 miles.

Over 15 years ago, my father had changed out the y pipes and installed 2.0” true stainless pipes with some stainless Sonic Turbo mufflers.

I’d love to add 20 or so more h.p.( at least) and have a meaner sound. Wont ever race – just want to cruise on Woodward Ave. and turn some heads. Want a good idle but with quick response zero to 60/70 mph.

Current plan is to install a new cam, lifters, and timing chain. Considering a 268 Comp Cam set and keep the factory carb and manifold.

Looking for suggestions for a cam manufacturer and spec and am wondering if I should ditch the exhaust and install headers and chambered pipes.

Anyone recommend a good cam for the above and thoughts about the headers/exhaust? What about the manifold?

 

[The73vetteman]

Well let me be the first to take a stab at answering this.

My first thought is that I would stay stock and accept it aint never gonna be a real race car. Why? Because although right now 77s are kind of unloved I think that will change and people will pay a premium for originality.

But, if you want to make changes, save the old parts so that you, or the next owner can get back to stock if you choose.

So what changes to make? I don't think I'd worry about the cam until I'd attended to the breathing. Headers seem like a popular, although kind of expensive, upgrade (and I guess you'd change the exhaust at the same time.) My understanding is that headers would give you maybe an extra 20hp on the stock L48.

A new carb and intake are also expensive, and I believe they will make another 20 or so hp. So you've spent $2k and got 40hp more. Good return on investment? Only you can decide.

Beyond this I think you're in to engine rebuild territory. At this point the sky (and your wallet) are the only limits.

BUT.... if you're going to put $3 - $5k into the engine, maybe you'll want to consider a crate engine instead. Give it some thought and let us know what you decide.

John

 

[bossvette]

for more get up and go a rear gear change will do more then any minor engine work especially from a 3:08 to a 3:55-3:70

 

[Koop]

I’d love to add 20 or so more h.p.( at least) and have a meaner sound. Wont ever race – just want to cruise on Woodward Ave. and turn some heads. Want a good idle but with quick response zero to 60/70 mph.

Current plan is to install a new cam, lifters, and timing chain. Considering a 268 Comp Cam set and keep the factory carb and manifold.

More cam = meaner sound. Carefull on the choice of cam, you can lose the low end response. I don't think a 268 is going to get the sound you're looking for.

Go to some shows, listen and ask. I got sucked into a ZZ383 with Thorley Headers and Magnaflows because of the way one sounded at the Corvette shop.

 

[KarlosM]

73 vettmen, Thanks for your advice. I agree with your logic, but I'm attempting to get keep it mostly stock-hence my avoidance of a crate motor. Its getting one too many oil leaks so I thought Ill pull the motor, put a new gasket set on it, and switch out the cam while its out. Your right, it will never be a rocket, but I'd like to get a little more performance and sound.

Think I will first put a cam, headers, and exhaust. If I still want more performance then I can change the carb and manifold afterwords.

I probably should go "listen" to some cams. Just wondered if anyone else has re-cam'd a L48 and what they used.

 

[LT4man]

I would pull your L48 out. Put it on a skid and wrap it in plastic.

Drop a 355 HP ZZ4 crate engine in!

You will have a constant smile on your face. If and when you decide to sell, just let the new owner have your original engine.

SAVE THE WAVE!

 

[The73vetteman]

Drop a 355 HP ZZ4 crate engine in!

I like the sound of that, but how will everything else hold up to that much power? Can the auto trans and diff take it without upgrade?

I have the regular 4spd (the M21?). Could this handle 355hp?

John

 

[LT4man]

Yes!!!!!!!!

But just to be on the safe side:

Contact Evolution1980.

Nuff said!

SAVE THE WAVE!

 

[MoeJr]

gears are definitely bang for the buck but remember to change the speedo cable gear to the appropriate one to keep it accurate.

Try the Comp Cams XE series cams. Maybe say an XE268 cam with 3.55 gears and 2000-2500 stall converter and you should be right where you want to be. You can get a nice meaner sound too by going to a chambered exhaust system. I put one on a friends 74 Conv and it sounds nasty. That car is running a 2500 stall and a 350/350 Cam.

 

[Koop]

I like the sound of that, but how will everything else hold up to that much power? Can the auto trans and diff take it without upgrade?

I have the regular 4spd (the M21?). Could this handle 355hp?

John

Your M21 would probably take more HP than my TH400. I put a 425HP/460TQ ZZ383 crate in front of my pretty much stock automatic (2,100 stall converter) and "original, never been rebuilt 3:08 rear end". The car takes the extra HP just fine!

The best sound my L48 ever made was hitting the garage floor! Don't bother with the plastic wrap, give it a burial at sea!

 

[GerryLP]

...My first thought is that I would stay stock and accept it aint never gonna be a real race car. Why? Because although right now 77s are kind of unloved I think that will change and people will pay a premium for originality....John

I would pull your L48 out. Put it on a skid and wrap it in plastic...

Well said! Even with plenty of money available, it doesn't mean that you'll find original or replacement parts. A lot of N.O.S. is also becoming unavailable.

If you're going to play with the Vette, then the crate motor option is by far the most safe and convenient way. Please, do keep all your original parts. You'll be glad you did.

GerryLP:cool