500 CFM for my Fastburn 385

[TheRoaringEagle]

shaker455, i do have some questions concerning my 750 cfm holley 4160. first off it was the recommended carb cfm for this crate engine according to GM. but the from calculation it seems it would be less for the cid. maybe around 600-650? anyways i noticed the engine runs slightly rough, and especially stumbles when i initially accelerate from idle. it feels better when i run past 1500 -1700 rpm. that combined with fuel smells, it seems like it's running pretty rich.



i haven't tuned the carb at all - it's running straight from the box. what do you suggest i take a look at?

also i'm new to manual choke and cannot pinpoint when i would use it. it seems to start up fine without the choke.

thanks for your help!

[TheRoaringEagle]

parker print - jeez, that's alot of horse power gone! i'm running a turbo 350 and with 3.42s it sucks on the freeway. if the speedo is accurate i run around 65mph at 3,000 rpm. i want a 5 or 6 speed but considered a 700r4 or 4l60 just because it would be easier to swap in.

how's your cruising speed? like around 65-70 mph? other than power lost, how's the 700r4?

[Shaker455]

TRE,
What is the list # on your 4160 that's on the front of the choke tower?

Did this carb come with the engine or did you buy it seperate?

The first thing you need to look at is the throttleblade position in relation to the transition slot in the baseplate ...so you have to take the carb back off and flip it over to look.

It's the veritcal slot that's uncovered by the blade as it opens....

The throttleblade stop screws should be set so both front and rear transition slots appear like a little square....in this position you can begin to tune the carb properly.

Now where your intinal timming set and how much vacuum are you pulling?...vacuum advance disconnected.

How many turns out is your idle mix screws?

Also how is it jetted?

[PARKERRS]

65-70 mph is around 1750 rpm. I like the 700r4 but sure hate the cost in hp. I've got another Camaro in the starting phases and it WILL be a Tremec 5 speed. I did this one with the auto so my wife could drive it on occasion, she refuses to drive a stick around town, and dislikes shifting period. Thats alright though it means the next one is all mine.