Setting the timing on my 383

[Harlow]

Just picked up my new Craftsman dial back timing light. Do NOT buy the Actron digital timing light from Sears...its a piece of crap. Both of mine didn't work brand new out of the box. I just checked my timing. The car does best at about 25* initial. The total is 40*. Its all coming in way to quick. Its all in at about 1700 rpm. So, I think I'll just turn my initial back to about 23 which should give me about 38* total(does anyone know how to limit the mechanical with the mp distributor? If so I'll just do that). And since I've got the MP distributor I'll just get a spring kit and put in some stronger springs. How bad of an effect would this have on the engine? I notice that it takes off nicely, but pretty quickly it starts to weaken and sort of stumbles. Now that I'll have the timing sorted out I can also tune the primary circuit, which could also be part of the problem. Let me know what you think.

[deputycrawford]

Alright. I am saying this in the kindest way. I am glad you have posted here to learn it the right way but you must give us much more information on the build to let us tell you how much timing your engine might handle. Mostly we need your cam specs, compression ratio and head specs and we can tell you much more. I will give you an area to start with. Most street builds like around 14ish degrees of initial timing and a total of 34 to 36 degrees. All of your timing should be advanced between 2500 and 3000 rpms. You sound like your timing is either way too far advanced or something is off scale. Too much timing would explain why your car falls off at higher rpms and starts to stumble. Set your total timing at 34 degrees at 3000 rpms, then see what the timing is at idle. That will tell you if you have to narrow the advance. Then drive the car and see how it revs. If it revs OK then work on the timing curve so it backs down to around 14 degrees at idle. Of course a different cam or engine combo will like different settings but you will be in the ball park. It sounds like you should just work on stronger springs, or at least one, so the timing advances later. Well, I will stop rambling on until I hear about your engine specs. Remember, the more the better.

[Harlow]

Alright. I bought the car non running and it had an engine that had been built about 6-10 years ago . I got it running and found that it was a pretty crappy build. I've gone through and changed everything except the cam and bottom end. There are a few unknowns on the engine which is quite annoying. I don't know how much head work the car has had, all I know is it has double valve springs. Besides that I don't know what else, if anything, has been done to the heads. I also don't know what stall converter the car has. Now for what I do know:

383 .030 over
comp cam 292 .510
Added Rhodes hydraulic lifters and adjustable rockers (set to a .02 gap) to bring the duration down
Edelbrock performer rpm intake
Edelbrock 750 mechanical secondaries (also have a holley 3310 I'd like to rebuild and try)
Headers
MP electronic Ignition

I'm not happy with the way its performing. I can't even get it to break the tires loose at all if I punch from a dead stop. The car came from the factory with 3.23 gears, but I've never confirmed that those are still in the car. I plan on checking in the next few days. Is this all the power this combo should make or is something off either tuning, stall, gears, something?

[deputycrawford]

With that much duration on a cam you will want at least a 4.10 gear to get the tires to turn. You will also want around 18 degrees idle timing and around 36 to 38 total timing in by 3000 rpms.

[Harlow]

The duration should be at about 270 now. Its really noticeable at idle how much its tamed down. What exactly does the stall converter do?

Do you think I should change the cam to say and engle K56 or do you think I should change stall and gears to try and get this motor where I would like it? Ron had suggested I change to one of the engle cams. I'm thinking I'm going to take his advice now. Does anyone have a similar build with similar gears I could compare the performance of my current build to?

[deputycrawford]

I would say to change the cam to the Engle K56. That is supposed to be an awesome cam. You should be able to keep your converter and gearing. A stall converter is just a torque converter that is made for a higher stall for big cams. Big cams don't make big torque until they're wound up so the bigger stall is needed to keep the engine from felling lazy. The big gears also keep the engine from bogging on the start. If you go with K56 you will not be disappointed. The only other thing I would change is to get rid of that carb. It is an OK carb for a completely stock builds but does not fit a larger cam build. Do you have an off idle stumble when you take off at part throttle? If you do then you are not using the idle well of the carb. Turn the two idle air adjustment screws in the front of the carb, all the way in and all the way out. If they do not do anything than the carb is not using the idle well. You have had to turn up the idle too far to off set the low idle vacuum from the big cam. I run a Barry Grant Mighty Demon. Others live by the Holley HP carb setup. Both have multiple idle circuits and both are great. In short, change the cam to a more streetable K56 and the carb to a Holley type and you will feel like an entirely different engine is in the car. I hope that helps and other should chime in also.