I have a 86' z28 with a carbed 350 from a c10 pickup (87-89 orginal fuel injected) with a mild cam, edlebrock carb 600ish i think (cars arn't really my forte) and stock rear end as far as i know. i know the gears arn't doing me any good but i believe it sould be faster. since i've had the car its gotten a tune up, and valve job but thats about it. the car feels powerful untill i put the pedal to the floor then its just shitty. so i figured i'd see what it could get 0-60 and i ended up with a VERY dissapointing 9ish seconds (which ironically is about what i get for gas mileage on a good day) anybody got any ideas? sorry if this is similiar to my other post but with stats like these you might have complaints to. (the truck this engine came out of could probably do 0-60 faster lol)

 

and i gotta pay to fix a rim crack, my car doesn't run off gas i just sign my pay check and put it in the car

 

is your transmission downshifting properly? (assuming you have an auto)

 

This might be a carburetor problem. If not, is the distributir working as it should? Which one are you using, anyway? Could be your centrifugal advance is seized. Another possible thing to check is a clogged catalytic converter.
I'm reaklly not clear if you feel it's a tuning problem, or a possible mismatch of parts. Still, verify all of the above first. If that doesn't get you the results you're after, then it might be time to go inside the engine. If it's currently running fine at small throttle openings, then I would think there's no problem in the valvetrain.
If it is a parts mismatch, I'd start by suspecting the heads. Pop off the valve covers and post the casting numbers so we can tell what you have.
This is how I'd start.
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Oh, and how certain are you that it is a 350 and not a 305? If you look behind the driver's side head, from above, you should be able to see either "5.0LG" or 5.7LG" cast there.

 

yeah its an auto and the trans feels fine

 

the muffler shop told me my cat was gutted, all i know is its an HEI distributor and its working fine (as far as i can tell). ever one seems to think its a tuning problem, i was thinking something might have been up with the carb(would it be this slow if it was only using two barrels?). the guy who did my valve job got the numbers off the block (thats how he figured it was a 350 outta a 87-89 c10). ok i'll see if i can get the number off those heads tommarow (hopefully).

 

Secondaries not opening doesn't explain 9 mpg. I know several guys on here will badmouth your carb, but I've had good experiences with an Edelbrock 600.
If it's a timing problem, get a dial-back-to-zero timing light, and see what kind of timing curve you're getting. at WOT, you should be getting like 34-38 degrees total advance by 3000 rpm.
Also, do a WOT run, then kill the engine immediately and pull a spark plug. Is it wet with fuel? black with carbon/soot?
Once you find the problem, if it isn't the spark, you could contact edelbrock about dialing in the carb you have, or you could simply try another carb.