Thread: small block tuning

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Hi Ive got a question about my ignition. Chev350 new edelbrock carb,intake,timing chain,headers new cap and rotor,new wires spark plugs etc. The problem is it runs great throughout the rpm range in neurtral but as soon as I drop it in gear it still runs good at idle but as I try to increase the rpm it spits and backfires it is timed properly and also has new points gapped properly. My guess is it has somehting to do with the distributor or possibly the vacuum advance? could I solve this by doing a electronic ignition conversion like the crane cams xr1 or the like ?
Any help would be appreciated .

I am not trying to start anything but why are you still running an old points style distrbutor?I see on e-bay brand new H.E.I. distributors go for less than $100.

i second that thought he was going to say it wont idle in gear scared me for a second

I am having a similar problem.I have a '67 327 with edelbrock intake and carb, MSD hei distributor + wires, and headers.I will get it running good then I'll fire it up the next day and it's a dog.Recently it's back-firing when I let up on the gas while cruising but runs fine if I get on it also it seems a little sluggish off the line at times.

This eengine was "professionaly tuned" at my local dyno tune specialists shop. I dont think that they put the engine under a load and therefore didnt see what happens when its in gear.

A couple of thoughts: Are you running too lean? Dyno tuning is usually done at wide open throttle, starting at 3000 rpm and my dyno tech did nothing to tune my engine for cruising. Are you getting enough fuel? Do you have enough pressure to feed the carb? My dyno people used their own electric fuel pump system to feed my carburetor.

forgot to mention a brand new holley fuel pump. and as Ii said earlier it only craps out when under a load but runs great in neutral at any rpm. but thanks for the thoughts

Do you have an EGR valve or a block off for one. If you do, is it plugged? If not, and you have a block off plate, is it sealed properly? That caused me fits a few years ago.

The manifold is a edelbrock eps performer non egr so the block off plate is actually just a flat spot on the intake flange.

Does anyone have any points of wisdom as I amabout to tnt the whole thing please please!!!!!!!

If no one here provides an answer, go the the Chevytalk website, register, and pose your question of the Performance Forum. There is a lot more traffic there.

www.chevytalk.com

Have you checked the vacume when you drop it into gear?
If it drops off below 10" or less you may have a power valve metering problem. Recalibrate with weaker springs if too low.

Sounds like its lean. How big is the carb? How far are the throttle plates open at idle? Is the accelerator pump working from idle and giving a good shot? Are the metering rods free to move?Just some things to check.

Just checked the vacuum advance canister and found it to be plugged.The carb is #1406 600cfm edelbrock with electric choke and is run as is right out of the box.

am having a similar problem.I have a '67 327 with edelbrock intake and carb, MSD hei distributor + wires, and headers.I will get it running good then I'll fire it up the next day and it's a dog.Recently it's back-firing when I let up on the gas while cruising but runs fine if I get on it also it seems a little sluggish off the line at times.

This may be a dumb question, but what is the best way to set the idle mixture?I too have the 1406 but manual choke.Not sure if this is the problem but I would like to double check.I recently rejetted and changed the metering rods with what edelbrock recommended when I moved to mich. from wyo (dramatic elevation drop) if that helps.It just seems that every time I fire it up it's running differently......damn gremlins!!