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  #31  
Old May 4th, 06, 12:25 PM
Super70 Super70 is offline
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Default Re: Need help with 383 Stroker

I have a similiar situation with my 71 Chevelle. It's a built 307 with 305 heads 600 cfm holley carb (I know, I know its not a 350, however the 307 runs great with some perf mods and there are many disagreements on this type of combo setup) I had the engine builder put in a hipo cam (I don't remember specs) and the engine really rocks upon having gained some speed (~25mph). Engine bogs at low speeds (I can't even get it to "peel out" when I powerbrake). I need a higher stall converter and some different rear gears. I'm using stock 10-bolt peg-leg rear diff and a TH 350 with a shift kit. Like I said, engine runs great and will bark the rear tire when upshifting, however I could use the changes (rear gears and higher stall converter) mentioned above.

My advice (even though I haven't made the changes myself on my car) is to a higher stall converter then work the timing and carb issues.

Last edited by Super70; May 4th, 06 at 12:48 PM.
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  #32  
Old May 4th, 06, 12:55 PM
kirkwoodken kirkwoodken is offline
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Default Re: Need help with 383 Stroker

What JasonSnider said! Find somebody in your area that has a successful race car, and see if he will teach you what you need to know. It is far better to learn to do something yourself, than to have to depend on someone else. The most important thing in life is learning how to spot BS people. Most who read your post understand that the "12 hour guys" are BS people. Go to some races and talk to some people that run well. Ask if you can help them wrench in return for learning. Don't expect something for nothing. This has worked for me.

Going from a 4 speed to a trans/brake cost me about $2200. That was for xmission,convertor, shifter, cooler, changing exhaust crossover, different crossmember, deeper trans pan, better drive shaft, a lot fluid. Still don't have a blanket, but will be getting one soon. I'm saying this just so you know what you can get into with a 'simple' transmission swap. (And the convertor should have a snout for a 400 crank.)
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Last edited by kirkwoodken; May 4th, 06 at 1:11 PM.
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  #33  
Old May 4th, 06, 1:58 PM
69-CHVL 69-CHVL is online now
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Default Re: Need help with 383 Stroker

I look at it this way, do what you can for free before you start laying out a bunch of cash for other things that may not solve the problem. What if he lays out big $$$ for a converter/trans, and it still has the problem?

I am NOT disagreeing that a converter is not needed, but how good is his motor gonna run if his timing is a 6*-8* initial right now?
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  #34  
Old May 4th, 06, 2:25 PM
kmchugh kmchugh is offline
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Default Re: Need help with 383 Stroker

Yeah, check the simple stuff first. My 383 likes 16* initial. Your stumble could be a timing issue, and or carb tuning issue. My 383 likes to run fat, so I have my floats set just over the sight plug. Check your carb to make sure the accelerator pumps are squirting gas into the bowls, front and back. If you have had any backfires, replace your power valve. Get the engine right, then you can always add more stall. What gear are you running in the rear?

P.S. Check for vacuum leaks, like a cracked base plate too.
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  #35  
Old May 4th, 06, 2:31 PM
sschevellefan sschevellefan is offline
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Default Re: Need help with 383 Stroker

Quote:
Originally Posted by 69-CHVL
I look at it this way, do what you can for free before you start laying out a bunch of cash for other things that may not solve the problem. What if he lays out big $$$ for a converter/trans, and it still has the problem?

I am NOT disagreeing that a converter is not needed, but how good is his motor gonna run if his timing is a 6*-8* initial right now?
I did`nt see anything about him only having 6-8* initial. once he gets a converter in there he would have to readjust the timing since he`ll be getting into the power range quicker so he`ll be doing it twice. I`m not going to play the "what if" game because anyone knows that cam is too big for the stock converter regardless if his timing is correct. i can`t understand why people are so hung up on the timing when it`s clearly the converter that is bogging down his car on acceleration. Even if the converter doesn`t help his stumble, he needs one anyway. I can`t be the only one to understand how much converter a cam like this needs? It`s not the same as a 4spd car where you can just rev it up to whatever rpm you need, you actually need a converter to do that for you with a automatic car.
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  #36  
Old May 4th, 06, 2:56 PM
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Default Re: Need help with 383 Stroker

Anthony...we don't KNOW where his timing is. He needs alot of it regardless w/any cam. All I'm saying is check it, and I'll bet that its too low. His shop is suspect so everything is questionable.


What about gears? What if there's only 2.73's or 3.08's? He gotta do that too right?
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  #37  
Old May 4th, 06, 3:19 PM
sschevellefan sschevellefan is offline
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Default Re: Need help with 383 Stroker

again ,his converter is too small and timing will never change that. I`m sure he needs to time it correctly but his timing needs may change with the higher stall converter.

as for the gears, hell yes he`ll have to change the gears. I did mention that in one of my earlier posts.

Have you ever had a car with a performance motor and a automatic? The need converters. You just can`t say, bump the timing up, it will run better. It`s not going to let the motor get into the power range that it needs to be in to run worth a ****.

I`m not trying to be a jerk but I`ve been around long enough to know that he needs a bigger converter, first and foremost. Then set the timing and carb and the thing should run great. Running a big cam with a stock converter is a mistake that many people make that are new to the hobby. I`ve said it enough times so as far as I`m concered I`ve said all I have to say on the matter. Once he gets a converter in there he`ll realize that it runs alot better, and gears will help also.
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  #38  
Old May 4th, 06, 3:39 PM
Drewz68 Drewz68 is offline
 
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Default Re: Need help with 383 Stroker

Gentlemen, gentlemen this info is fantastic. However, there is no need for the hostility. I will try and answer the questions that are pouring in. I dont know the gears, as far as i know it is a stock 10 bolt, the car was originally a 307 with a power-glide. Now for the timing, i spoke with the "performance" mechanic this afternoon, he does not remember the initial timing, but he thinks the total is around 36*. I have done some reading on setting ignition timing curves and some of the responses have said the initial timing should be 14-16*. At 14-16*, what should the total be? Should i be concerned about detonation if i advance the timing too far, what will happen if the timing is too advanced? I have borrowed a timing light and have the article in hand (it is on the Chevy High Performance website), i am going to at least check it tonight. I am sure the converter is too small, but i agree with Vince and Kevin. I am going to check the least expensive stuff first. Since i am going to attempt this on my own, has anyone got any advice on what not to do?
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  #39  
Old May 4th, 06, 3:59 PM
sschevellefan sschevellefan is offline
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Default Re: Need help with 383 Stroker

14-16intial and 36 total should be fine. If thats what it`s set at don`t mess with it unless you do have detonation, then back it off untill the pining stops.

if the tranny is a pg then that along with the stock converter will really bog down your engine. if you advance the timing too much your starter might have a hard time turning the engine over and it could run hot as well.

this isn`t a timing issue and I can`t believe that so many people think it is. if you want a cheap converter, go down to the local tranny shop and ask for a converter for a 4cylinder vega. They are available for the pg or th350 tranny. I ran one years ago and got 3000 rpms out of it. they should be less than $100. I`ll bet that it wakes your car right up.

good luck with the car, I`m done trying to give my advice on the issue but I`ll continue to watch it to see what you come up with.
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  #40  
Old May 4th, 06, 4:04 PM
Drewz68 Drewz68 is offline
 
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Default Re: Need help with 383 Stroker

Thanks Anthony, you have been a great help, i will put the timing light on it tonight and check it out and let everyone know what i come up with.
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  #41  
Old May 4th, 06, 4:15 PM
jakeshoe jakeshoe is offline
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Default Re: Need help with 383 Stroker

Quote:
Originally Posted by sschevellefan
can you explain how the timing is going to fix the lack of converter? Timing isn`t going to fix the main problem. like I said, it doesn`t matter about what it does in park at this point and he just posted that there isn`t a problem reving it in park anyway so that takes care of that. he needs a converter, plain and simple. anyone who knows anything about performance motors will agree that that cam is way too big for a stock converter. He needs to put a stall converter in there and then set the timing and tune the carb.
A 234/244 cam in a 383 with decent compression is not a very large cam. it is a pretty mild to moderate street performance cam and I would be willing to bet it isn't on a very close LSA, so idle quality is probably decent.

A stock converter will stall to 1700-1800 rpm behind a torquey setup in most cases.

Although he may need a slightly over stock converter, 2200-2500 range, it isn't what is causing his issue.

He needs to do the basic tuning of timing and carb first. For one it is easier and cheaper.

One thing you may try first thing is to hook your vacuum advance to manifold vacuum, this will bring the idle timing up without changing the total timing under load.
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  #42  
Old May 4th, 06, 10:13 PM
Drewz68 Drewz68 is offline
 
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Talking Re: Need help with 383 Stroker

Well gentlemen, here it is. The timing was at about 8*. I advanced it to about 14* this has made a big difference. She still hesitates some, so i think that a converter will eliminate the rest of the hesitation, but i can get the one wheel wonder to spin a little when i hit the throttle. Big difference!!!! You all want to know the best part about it, i did it myself! With a little research, a timing light, and the info and encouragement that i got from all of you, i turned this little problem into a "doityourself" project. Now, is there anything that i should be watching, someone had mentioned that it may run a little hot, someone else mentioned the possibility of detonation. Thanks again, this is one of the best days of my new hobby!
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  #43  
Old May 4th, 06, 10:28 PM
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Default Re: Need help with 383 Stroker

Excellent...now get to 16* and 36* total and your hesitation will be gone. The total is what you have to watch out for.
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  #44  
Old May 4th, 06, 11:20 PM
daveseitz daveseitz is offline
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Default Re: Need help with 383 Stroker

Drew what kind of distributor do you have in there? Also have any changes been made to it. If you still have a stock unit ok it too may need some attention.
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  #45  
Old May 5th, 06, 2:32 AM
jakeshoe jakeshoe is offline
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Default Re: Need help with 383 Stroker

Drew,
14* is a good baseline however it is probably not enough "idle timing" for your motor and cam.

If you were to forget about total timing and all else for the moment, and use a dialback timing light, you will find that your motor will likely idle best with 25*+ timing.
Probably over 30*...

Fire it up, and keep advancing timing until it idles best. Smoothest fastest idle with the most vacuum if you can get a vacuum gauge.

You will likely have to reduce the idle speed screw and maybe re-tune the idle mixture screws because this will allow the engine to idle much easier.

Record this timing. You will want it to be the same later.

Reset your total timing so that it is approx. 36*, this is a good baseline and most SBC's with older style chambers like yours will run good here.

This puts your initial timing back at that 14* area.

Plug your vacuum advance into manifold vacuum. It will be a port on the carb that has vacuum at idle and all other positions.

Now check the timing. it will probably be a bit too much advanced.

You'll want to get a Crane adjustable vacuum advance kit, and use it to limit the amount of vacuum advance at idle to obtain the same "idle" timing as you recorded earlier.

This will put you at the best idle timing, and total timing.

The vacuum advance will not add timing at WOT under load because the engine has little vacuum at WOT.

So anytime you want to check total timing, unplug the vacuum advance.
Don't worry where your initial falls, let it fall where it may, it isn't very critical if you tune it with this method.

Hopefully this is easy to understand but if not fell free to PM or email me, or I'm sure others here can help you out.
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