77Maurice

We are restoring our 77 vette. We've overhauled the suspension, wheel bearings, ect.. But now its time for the engine. The stock L48 is below 200hp. This car will only be used for a nice drive every now and then, and does not need to be set up for track racing. BUT> I would like to increase the power and have a good sound coming from under the hood (and out the pipes). I will be installing headers and true dual exhaust. I want a good cam sound, so I am replacing the Cam. I am also considering going to a better set of heads. I plan on keeping the Quadrajet Carb. Without breaking the bank, I would like to know your alls opinion on specific Cams and Heads... (Brand, model, ect.), that work well together. Any advice would be wonderful!!! Thanks~

markids77

Heads are relatively big dollar items even if purchased used. May I recommend a "step at a time" modification schedule? Perhaps after you uncork the exhaust and maybe install an improved intake manifold, along with some "super tuning"... it will sound and move well enough not to need more? Then a cam change with your current heads. If your L-48 is basically healthy, just a few mods can wake it up plenty without burning a stack of Benjamins.

Gun Laker

I rebuilt my 1977 L48 last year. I have true dual exhaust, but used the stock ram's horn exhaust manifold. Some people do not like headers because of the heat issues. I put on an Edelbrock performer manifold (orginal one was cracked), had the heads reworked with a three point grind (the heads are not that great, (882 castings) but mine were in good shape so the work was not too expensive). Put in a dual energy cam from Comp and matching valve springs, flat head pistons, milled off some decking, used thin head gasket and got increased compression that way (about 9:1). I also had the crank turned. Rebuild the quadrajet myself with some very great results. This was the first time I rebuilt an engine and it took me some time and some trial and error. I am very happy with the results and the power increase results and the great sound. My car is a driver, not a racer by any means. It runs nice, lays a little rubber and sounds nice. Good luck and if you want any more thoughts let me know especially if this is your first rebuild.

cam cooper

i agree with markids77 change these things first leave the heads and cam alone dont get into the engine inless u have to with these upgrades u may be happy with what u have if not..... well we all know where this is going

77Maurice

Thanks for everyones opinions!! The L48 is in great shape. Most likely, for the sake of time and money, I may just rebuilt the carb, maybe get a new intake manifold, overhaul the entire exhaust system. This should serve the purpose pretty well. Maybe later make other, more dramatic changes... but by that time (if im wanting more power) I may throw a crate in it. I do have one more question, would I be able to swap out the cam with a Comp Cams cam, while keeping everything else stock? or would more work need to be done to the heads w/ an after-market cam?

78 C3 Light Corvette Blue

Just remember under 200 net hose power. Gross around 290

markids77

Comp has a cam grind which will work with your stock heads. Ask both here and at the Comp tech line if you decide to replace the cam... a "lumpy" idling cam will not be the best choice unless you build the rest of the engine to work with that cam. There's some science, and some "black art" to good cam chouce... and that choice is dependent on all the rest of the engine's parts as well.

BKbroiler

They stopped talking gross horsepower in 1971. A 77 L48 was rated at 180 HP net. No way its gross number would be 290. Thats 60% higher.

78 C3 Light Corvette Blue

http://neptune.spacebears.com/opine/horsepwr.html

jotto

From the page linked to above,
Drive train losses will sap some of the SAE net figure.

On a recent post, an engine was dynoed without accessories etc and then dropped in to the car where it was dynoed again. The loss came out at around 23% IIRC.

If you had 200 RWHP, assuming a 23% loss, engine would be pushing around 260 HP.

From the factory, a 77 rated at 180 HP Net would probably be close to 200 HP gross.