Hey there.
If got a 383 stroker with the hei distributor. My car doesnt seemed to be running right. I have a 670 street avenger carb on it. about 10.5:1 ratio, using 91 octane pump gas. Cant remeber what exactly sure what i should have my timing at. tried to fiddle around with the timing and carburator, nothing just seems to be working for me. sometimes i will get back firing out of the carb. Adjusted the vavles a few times, they seem to be fine. Anyone have any ideas, of what could i do? Has a overheating problem 2, if that would have anything to do with it?

 

what are your cams specs? timing at idle has alot to do with your cam specs. what is your timing at idle? what is idle vacuum at idle in gear? where is the mixture screws at?
back firing out the carb could be the carb pump cam not right. does it hesitate when backfiring?
overheating is aggrevated with retarded timing.

 

my cam specs are about 490 exhaust and intake. or the exhaust is 510. cant remmeber something like that. descent size. my car is in a different town rite now, not sure what i have it at for timing now. and my vacuum is really low. under 10. mercury inches. misture screws r on the sides of the the carb in the front.

 

first of all you need some education. that said do some research and you will get there. read alot on here get some books ect....
I know the mixture screw location but you need to know where they are set at as in turns from full in. you need to understand whats happening and why before you start to tune your car other wise you will get nowwhere....

 

i no. its just im not near my car, and dont have any specs with me, im at school in a different town. just trying to get some ideas. ive tried lots of different things, just cant really tune the holley carb that good.

 

buy some books thats exactly what i did.
those holleys are very tunable and work excellent once the owner understands them.

 

Alrite dude i will get into it. Its just i spent so much money, and its not running the way it should be, not enough hp haha.

 

Hi,
I also have a 383 stroker that i just got done installing in my 83. After you have everything in and buttoned down start with your carb, turn both air fuel screws all the way in and back them both out 1 1/2 turns. At this point you should have your timing light, vacume gage and tac all hooked up and ready to read. Start out with 10 deg initial timing. If you have hydraulic lifters you need to break in your cam on initial start up, do this by running the engine at 2000 rpm for 12-14 min. Then you can adjust your timing, you want 34deg in by 3000 rpm. So 10 deg with your vacume advance pluged and the rest of the 34 with your vacumme and mechanical advance. There is a good timing article on chevyhiperformance.com about total timing and timing curves. Good luck.