I have an all original 76 L48. The engine needs to be rebuilt. Is it that important to keep the car completly stock, or this engine for that matter?

It all depends on many things. Do you plan to keep it a long time and never sell it? If so, the originality issue is not one. But if you plan on selling it in years to come, the original motor is big item on value. If you have the money, I would take the engine out and store it, buy a crate motor and put it in. If you ever want to sell the car, you still have the number matching motor. Just my 2 cents.

Well, I plan on keeping the car for a while yes, but eventually sell it. I would like what you have and thati s a 71 conv. I would rather have more performance than the L48, but now knowing this car is complete in EVERY DETAIL, I hate to molest it.

You could rebuild the engine with a few modifications.
A slightly more agressive camshaft can supply more power and yet maintain a good idle. Going up to a 10:1 compression pistion would also help quite a bit.
If emissions are not a problem in your area you could install a 74 dual exhaust. It will fit perfectly, and that would add a few hp, but it will show. You could easily pick up 50 hp or so. Put in 1.6:1 rockers and new valve springs and you could get a few more. IF you want to spend some more cash, install larger valves and seats. With all of this you may get as much as another 75 hp, still have the "original" engine and keep good driveability. Or go with a crate engine already built a bit, and save the original.

I agree with kyster, unless you are going for NCRS gold or whatever, where the motor has to sound stock, adding some hidden hp goodies to the original motor isn't going to detract from the value. There are also lots of good vette manifolds from previous years, so you can keep the factory look, even if it isn't original. Just keep the old parts on a shelf somewhere. Joe

I'm with them, mod the original motor. If you have storage space I would build another motor and keep the stock one, but if that is not possible mod the original-an intake, cam change, more compression, and true duals would really wake the car up. I am partial to Tune-Port swaps myself. It can be installed with minimal mods to the car, one extra hole in the firewall for the harness and fuel line mods. Lots of low-end torque and if kept stock minimal chance to over-rev it (you can't feed a stock 350 TPI enough air to get over 5500-6000 rpm) and damage your original block. Fits under the stock hood, no problem.