just pickup a 67 coupe looking for comments
looking at putting in a 540 big block or a 434 small block it is a auto

Welcome to Team Camaro!

what you do with the car in the build all depends on what your plans for the car are. Personally I'm partial to the sbc, but there is no replacement for cubic displacement.

If you tell us what you are looking for, what you have and what condition its in, and what budget you are looking at we can give you some suggestions.

the car is in good shape does have a 383 with dart heads, 3 inch exhaust
plan to drive the car , like to have lots of ponies chasis is stock has traction bars, front disc brakes
just don't know if having bbc with extra weight is bad.

Keep in mind that sbc. parts are everywhere. Going to bbc. you'll be starting all over.

Converting to a big block is not cheap. Do a search and you will find all the "other" things you would need. Why swap out the 383 ? IMHO I would spend my money on upgrading the suspension and getting the 383 to hook up. Eric68 should have lots of pointers for you.

Agreed. I'd stick with the 383. They're notorious for putting down 450+ HP on pump gas. Pull the valve covers and check for some valvetrain goodies. 3" exhaust is a bit big for a 383, I personally run 2.5" true duals on my 81 Vette with a 383. It keeps enough backpressure around so that I don't lose too much torque at low RPM's. But as stated above, it all depends on what you want to do with the car. If you want to drag it, then there's no replacement for displacement. A 454 with aluminum heads doesn't weigh a whole lot more than a 383 with iron heads. Plus, we'll buy your SBC stuff off you along the way to help finance your project. ;) Congrats on the purchase, and welcome to the forum. Prepare for lots of head turns when you're driving that thing. :D