Hello guys, I have a question about recurving my distributor in anticipation of what Demon carb instructions say I need to make the idle circuit to operate properly. A little about the engine first, it`s a 396 built for my 68 camaro, 10:5 compression, cc 11-242-3 extreme energy 268 cam 224-230 @515 lift (looking more for drivabilty and mid range torque than upper rpm hp) Edelbrock 110cc heads and rpm air gap intake and Speed Demon 750 mechanical secondary.
My question is Demon recommends to set my initial timing to 14-16 degrees and my advance all in to 34-36 degrees. To achieve this I will need to lower the amount of advance. I know I can use a timing light to see where I am at once I initially start my engine, but was wondering if anyone had done this and can offer advise on what worked for them as far as what you might have done to tune your timing curve, what kit or what you found successful to make this carb work properly ( I have already looked inside for debris and found none).
Thank`s for any advise .

What kind of distributor?
My msd came with a selection of springs and bushings to set the advance amount and rate. Others may or not.

The specific kit you need depends on which distributor you run.

Regardless, you want one that contains different wieghts and or bushings to limit the amount of advance. Another method is to weld on either the slots or the wieghts to limit the advance.

You're gonna have to be careful. That cam with 10.5:1 compression will build a LOT of cylinder pressure. You'll need premium for sure, and a very careful tune to keep her from pinging.

in addition to jims post, the bg reccomendations are just that...reccomendations...every individual motor will differ a little on timing depending on state of tune, elevation,exhaust size, cyl head design, and soforth...you will have to spend some time to figure out your specific curve requirements...but definately use the bg suggestions as a baseline...is the carb giving you probs???is this why the timing questions, or just an additional prob???i`ve found demons to be great carbs, but i put ` on a 468 firebird, and it wouldnt idle for crap...on a totally unrelated problem, i increased the exhaust size from 2.5 to 3 inch mandrel bent exhaust, and the car idles fine now and runs great in the idle circuit...go figure...lol...

My distributor was bought at a local speed shop, no name ,billet GM replica, 60,000 volt coil, brass cap, recommended as an excellent distributor, but it did not come with any recurve parts or indication of what the curve may be. I may have to purchase a Mr.Gasket HEI recurve kit I saw at the local autozone and just play with it some when I get it running.May need other adjustments as suggested.
Jim, you are scaring me a little about cylinder pressure and fuel requirements. I certainly am not an expert engine guy and don`t claim to be, but when I chose this cam I was going by my prior experience of getting by with a little more compression with aluminum heads to avoid detonation. I knew it would probably require 93 octane but certainly don`t want to be buying anything above that as this will be driven on the street and maybe taken on some 2-3 hour trips. Have I made a mistake in my choices??

I played with Patk's calc a lil, had to make some assumptions as far as actual specs. I put in what I know, then juggled piston dome size to get 10.5:1 static, then looked up and put in the specs for that cam.

DCR came in at 8.46:1

This is on the high end of pump gas reality. It's certainly do-able, but will have to be carefully tuned. A lot depends on the rest of the combo. I would have trouble with a DCR that high due to a stick shift and my tendency to lug the motor and let the torque pull me along, where an auto with a 2500 or 3k converter and more rear gear would never load the engine like that.

Engine mated to TKO600 and 373 rear. Not to late to change camshaft out as this is a work in progress if I am not going to be happy with this combo. Engine and drivetrain is in the car but front sheetmetal is off. What else do you need to know to get accurate read on this? Do you think this in reality is a decent combo or not? What would you suggest? Remember, torque is king, horsepower is just a number to me on the street.

Using the numbers I have and pluging in 10 degrees more duration drops the dcr to 8.2. That is a good number, it will not be ping limited on timing with premium fuel.

Based on my experiences with a 383 SB and 5 speed, I'd suggest you go up "1 size" on your cam. All positives, no negs that I can see. My 383 w/270 cam is practicaly a "truck motor" I'm going up 10-15 degrees the next time I have it apart. Your 10.5:1 comp is perfect for a 280ish cam.