have a 350 block , orginal 302 crank, original piston and rods, brand new still in box 140 original off road cam, have 1968 double hump headsand was wondering if i should use these heads or some modern alumiumn head. trying to get thez302 sound and reving .

If your 1968 double humps are in decent shape then that is what I would use if your main concern is the sound and revving. What sounded good and revved good in 1968 can do the same in 2012.

Agree with Michael, I'll add if the 186's need rework, compare the cost of a new set of comparable alum heads.
Paint the new heads the same color as block to disguise, but then by painting alum, the paint contains the heat as alum will not be able to 'radiant' heat.
But, I wouldn't be too concerned about the heat retension.

Agree with Michael, I'll add if the 186's need rework, compare the cost of a new set of comparable alum heads.

If they are 1968 model heads they will be 291 castings and not 186. That being said, what year car is this going to go in? The 291 heads do not have the accessory holes like the heads from 1969 and newer for mounting accessories. Just something else to consider.

The 291 heads do not have the accessory holes like the heads from 1969 and newer for mounting accessories. Just something else to consider

I run the small chamber fuelies (thats what camel humps are refered to down under) for the hi compression on my 350...
To get around the no mounting holes for the alternater, a 3 or 5mm scrap of plate that mounts under the water pump bolts (longer bolts) and to the back of the alternater holds it very well...get it chromed and Bobs your uncle...made mind over 20 yrs ago..

Vortecs modified for more lift and beehive springs. Plenty of dualplane intakes available.

they are 186 heads with 11 th month stamped on them for 69 motor

I like the 170cc Edelbrock E-tecs for small cube engines.

They are vortec copies in aluminum.

Running the risk of repeating myself, if you use the original 30-30 grind you are most of the way home. It is a very forgiving cam. You can run pump premium with no problem. 18-18 timing with 15 in the vacuum advance (full manifold vacuum) , up the primary jets, run headers and it will drive like a nice 327. My head gaskets are .026" so the static compression is a scosh under 11:1. But it still screams. I would guess the 140 cam would act about the same.

Ted, take some time and read about the trials Aaron went through with using the 140 cam (and others) in his 302. Basically, the 140 cam will work best with the heads it was designed with (the 186's).

http://www.camaros.net/forums/showthread.php?t=155736

And if that 140 cam is NOS, sell it and buy an Elgin grind. You'll get a boat load of money for it, and then pay only $100 for a stronger, higher quality aftermarket cam. Its a no brainer.