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  #46 (permalink)  
Old 12-01-2013, 12:09 PM
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"This engine has to be streetable and reliable before a power house. For that reason i do not want to put too big of a cam in it. If I fall a little short of 450hp than so be it."
"In the article that you posted it said that 5-7 hp could be gained from longer rods. I am not expecting anything spectacular from the longer rods, but cost between the two different lengths is minimal (about $100) I am simply trying to figure out if the longer rods are worth the extra $100 taking into consideration what I have read about rod ratios, side loading, power gains, ect."

a lot of the LS engines rev to 6500 rpm
if you want to use the cam you chose,go for it,,,

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Old 12-17-2013, 05:16 PM
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so we finally ordered all the lower end parts and the heads, so I'm starting to move on.
First question is about carbs. 750cfm sounds like the carb to use for this build but what one? I know that I need a vacuum secondary, and I know the difference between manual and electric choke but beyond that I don't know what the defference between carbs is. why should I pick one kind or brand over another? What should I be looking for?

Also, how do I know what speed stall converter to get? I will have 10:1 compression ratio with a comp 08-432-8 cam
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Old 12-17-2013, 08:42 PM
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what stall do you think you need?
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Old 12-17-2013, 08:50 PM
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I'm not personally a fan of VS carbs, and if your still planning the OD trans then we can assume it will have a fairly deep gear...
If its mine, I'm using a 3000stall with lockup for a 230/[email protected], and a 750DP, 411 gears and call it good.
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Old 12-17-2013, 08:54 PM
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Here's the cam card.....cam makes power beginning at 2200 on up to 5800. Following the F-BIRD'88 line of thinking, I would advise a 10" converter, stalling at 3000.
08-432-8 - XTREME Energy™ 1987-1998 305-350 Originally Equipped With Hydraulic Roller Camshaft, Except LT1 and LT4.

The intake valve closes at 41 degrees ABDC, creating a DCR of 8.535:1 when used with a 10.0:1 SCR. This should be an excellent build, a real tire-skinner. I don't recall the squish you were shooting for, but it needs to be 0.035" to 0.045" as insurance to work with the 8.535 DCR.

Since the motor will rev to 3000 stall (theoretically), it makes little sense to plot an ignition curve that would terminate before 3000. Just a waste of time. Verify TDC with this tutorial, then lock out the advance weights in the dizzy and use 34 degrees at the crank with a "known-good" timing light and a degree tape on the inertia ring. Experiment with an adjustable vacuum advance until you find the sweet spot.
http://www.crankshaftcoalition.com/w...op_dead_center

You need a NC (normally closed) pushbutton switch to interrupt the power line from the switch to the coil. Pushing the button with your left hand at the same time you turn the start key will allow the motor to turn easily because there is no fire to the plugs. Once the crank is twisting up pretty good, let go of both the push button and the key switch and the motor will be running, no sweat, no fret.
http://www.ebay.com/itm/like/190715624075?lpid=82
This is a 12v, 10 amp switch that is normally closed (passing electricity) until you push it and interrupt the flow of electricity to the coil.

bygddy makes a good point. A 3000 stall converter will support a double pumper carb. A lesser stall converter might work better with a VS carb.

I would consider a 3.73 or 4.11 rear gear and 27 inch tires.


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Last edited by techinspector1; 12-17-2013 at 09:19 PM.
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Old 12-18-2013, 06:29 PM
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Its interesting that you are recommending a mechanical secondary carb. Everywhere I have looked it simply stated that a mechanical secondary carb is for a manual trans and a vacuum secondary carb is for an auto trans. What are the advantages of using a mechanical secondary carb with an auto trans vs a vacuum secondary?

Quote:
Originally Posted by techinspector1
Here's the cam card.....cam makes power beginning at 2200 on up to 5800. Following the F-BIRD'88 line of thinking, I would advise a 10" converter, stalling at 3000.
08-432-8 - XTREME Energy™ 1987-1998 305-350 Originally Equipped With Hydraulic Roller Camshaft, Except LT1 and LT4.

The intake valve closes at 41 degrees ABDC, creating a DCR of 8.535:1 when used with a 10.0:1 SCR. This should be an excellent build, a real tire-skinner. I don't recall the squish you were shooting for, but it needs to be 0.035" to 0.045" as insurance to work with the 8.535 DCR.

Since the motor will rev to 3000 stall (theoretically), it makes little sense to plot an ignition curve that would terminate before 3000. Just a waste of time. Verify TDC with this tutorial, then lock out the advance weights in the dizzy and use 34 degrees at the crank with a "known-good" timing light and a degree tape on the inertia ring. Experiment with an adjustable vacuum advance until you find the sweet spot.
isn't a 3000 stall pushing it for a street car? I don't want to get too carried away with the stall but at the same time I don't want this car to be a dog off the line. If you think it needs a 3000 stall than that is what I will go with becuase I don't even know where to start in picking a convertor lol.

Quench distance will be .038 so I should be all good there.

I haven't looked into ignition systems too much but what you stated intrigued me. So you are saying set up base timing based on stall speed. Then mess with the weights/vacuum advance from there for higher rpm? So if I am getting it right 34 degrees is optimal base timing for an engine running around 3000 rpm. But it makes it harder to start because it is too much for the lower rpm. Also are you recommending a distributor with both mechanical and vacuum advance?
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Old 12-18-2013, 07:28 PM
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Quote:
Originally Posted by L_C99 View Post
Its interesting that you are recommending a mechanical secondary carb. Everywhere I have looked it simply stated that a mechanical secondary carb is for a manual trans and a vacuum secondary carb is for an auto trans. What are the advantages of using a mechanical secondary carb with an auto trans vs a vacuum secondary?



isn't a 3000 stall pushing it for a street car? I don't want to get too carried away with the stall but at the same time I don't want this car to be a dog off the line. If you think it needs a 3000 stall than that is what I will go with becuase I don't even know where to start in picking a convertor lol.

Quench distance will be .038 so I should be all good there.

I haven't looked into ignition systems too much but what you stated intrigued me. So you are saying set up base timing based on stall speed. Then mess with the weights/vacuum advance from there for higher rpm? So if I am getting it right 34 degrees is optimal base timing for an engine running around 3000 rpm. But it makes it harder to start because it is too much for the lower rpm. Also are you recommending a distributor with both mechanical and vacuum advance?
In my personal experience the mechanical always performs better for my intended usage. I drive my junk hard, and am not looking at fuel mileage in my toys. I'm also not very good at setting up a VS Carb and find them very frustrating. That's a "me" issue as I haven't spent any time learning. I know I followed the rule of thumb with 2 builds, both heavy cars and both small block street cars. Moderate converters, one with 3.55's and one with 4.11's.... I used a 750VS secondary on both initially, swapped to a mechanical 750 and went significantly faster. Both drove excellent and sharp with no noticeable transition when the secondaries open (for some reason the inexperienced seem to think feeling a bog and the a big punch when the secondaries open is cool lol....it isn't). Yes mileage suffered in both cases but it was negligible. A good 3000 stall is very drivable and with a functioning lock up will perform virtually as stock on the highway.
A stout motor with a 750DP (I prefer Quick Fuel but its mostly a personal choice) a 3000stall, (for off the shelf I like Hughes, I think its pn# 22-30EL for your 4L60E) and a 4.11 gear would work very well.
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  #53 (permalink)  
Old 12-18-2013, 09:10 PM
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383 stroker

Doesn't anyone build short rod 383's anymore? For a street engine I really don't see a down side. Seems no one wants to use SBC 400 (5.56) rods in anything and I buy sets cheap. Piston manufactures, (Mahle, Speedpro, Etc) are now making short skirt 350 pistons that will work with scat 383 cranks with short rods, (clearing counterweights). Only down side is lightening the crank during balancing. It's nice being able to chose from a wide array of 350 pistons for a short rod 383. For a engine only turning up to 5500 rpm, they work fine and are very cost effective to build. Just my opinion.
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  #54 (permalink)  
Old 12-18-2013, 09:18 PM
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Quote:
Originally Posted by bygddy View Post
In my personal experience the mechanical always performs better for my intended usage. I drive my junk hard, and am not looking at fuel mileage in my toys. I'm also not very good at setting up a VS Carb and find them very frustrating. That's a "me" issue as I haven't spent any time learning. I know I followed the rule of thumb with 2 builds, both heavy cars and both small block street cars. Moderate converters, one with 3.55's and one with 4.11's.... I used a 750VS secondary on both initially, swapped to a mechanical 750 and went significantly faster. Both drove excellent and sharp with no noticeable transition when the secondaries open (for some reason the inexperienced seem to think feeling a bog and the a big punch when the secondaries open is cool lol....it isn't). Yes mileage suffered in both cases but it was negligible. A good 3000 stall is very drivable and with a functioning lock up will perform virtually as stock on the highway.
A stout motor with a 750DP (I prefer Quick Fuel but its mostly a personal choice) a 3000stall, (for off the shelf I like Hughes, I think its pn# 22-30EL for your 4L60E) and a 4.11 gear would work very well.
I don't think I can improve on this answer.
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Old 12-18-2013, 09:22 PM
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Quote:
Originally Posted by Studebaker View Post
Doesn't anyone build short rod 383's anymore? For a street engine I really don't see a down side. Seems no one wants to use SBC 400 (5.56) rods in anything and I buy sets cheap. Piston manufactures, (Mahle, Speedpro, Etc) are now making short skirt 350 pistons that will work with scat 383 cranks with short rods, (clearing counterweights). Only down side is lightening the crank during balancing. It's nice being able to chose from a wide array of 350 pistons for a short rod 383. For a engine only turning up to 5500 rpm, they work fine and are very cost effective to build. Just my opinion.
I liken this to the old Hot Rodder's Axiom.....If some is good, more is better and too much is just right. If you leave people to think for themselves, they will carry anything out to the ridiculous where it won't work any more. It really pizzes me off when some geek automatically insists on 6" rods in a SBC.
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  #56 (permalink)  
Old 12-18-2013, 09:30 PM
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Quote:
Originally Posted by L_C99 View Post
I haven't looked into ignition systems too much but what you stated intrigued me. So you are saying set up base timing based on stall speed. Then mess with the weights/vacuum advance from there for higher rpm? So if I am getting it right 34 degrees is optimal base timing for an engine running around 3000 rpm. But it makes it harder to start because it is too much for the lower rpm. Also are you recommending a distributor with both mechanical and vacuum advance?
What I'm saying is that if you use a 3000 stall converter, then the motor will run up past where you would normally be tailoring the advance curve to have all the advance in by 2800. There is no need to have any mechanical advance curve at all if the motor is revving past the point where you would have the limit of centrifugal advance. Put the initial setting at the crank at 34 degrees, or whatever advance the combustion chamber design supports. Then, add any vacuum advance that you might want to play with. Do away with centrifugal advance and put all the advance in at the crank, except for vacuum advance.

With that much advance, the motor will want to kick back against the starter when starting the motor, that's why I linked the momentary switch. There are systems from aftermarket manufacturers like MSD that will have a cranking retard built into the system, but if you don't have one of those systems, then the momentary switch will work fine.
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Old 12-19-2013, 04:41 AM
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Quote:
Originally Posted by techinspector1 View Post
What I'm saying is that if you use a 3000 stall converter, then the motor will run up past where you would normally be tailoring the advance curve to have all the advance in by 2800. There is no need to have any mechanical advance curve at all if the motor is revving past the point where you would have the limit of centrifugal advance. Put the initial setting at the crank at 34 degrees, or whatever advance the combustion chamber design supports. Then, add any vacuum advance that you might want to play with. Do away with centrifugal advance and put all the advance in at the crank, except for vacuum advance.

With that much advance, the motor will want to kick back against the starter when starting the motor, that's why I linked the momentary switch. There are systems from aftermarket manufacturers like MSD that will have a cranking retard built into the system, but if you don't have one of those systems, then the momentary switch will work fine.
My only concern here Tech, would be the OD trans. I think in this case there should sill be a curve of some sort, say 18 initial, 34-36 total all in by 3000. Given the lockup converter I suspect there will be situations where the converter is locked and he is well below the 3000stall. Im not sure how he is controlling lock up function, but I know in many cases once into OD the converter will lock at a predetermined speed.
Having the mechanical all in, as well as vacuum may cause some running temp or pre-ignition issues at say 55MPH where the converter is locked and were at 2100rpm with all timing in.
I may be completely wrong here and if so please say so, I learn something new everyday and am happy with that lol.
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  #58 (permalink)  
Old 12-19-2013, 01:33 PM
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Quote:
Originally Posted by bygddy View Post
My only concern here Tech, would be the OD trans. I think in this case there should sill be a curve of some sort, say 18 initial, 34-36 total all in by 3000. Given the lockup converter I suspect there will be situations where the converter is locked and he is well below the 3000stall. Im not sure how he is controlling lock up function, but I know in many cases once into OD the converter will lock at a predetermined speed.
Having the mechanical all in, as well as vacuum may cause some running temp or pre-ignition issues at say 55MPH where the converter is locked and were at 2100rpm with all timing in.
I may be completely wrong here and if so please say so, I learn something new everyday and am happy with that lol.
I don't see any right or wrong, only different. Locked out may not work for the OP, or it may work. To err on the side of caution, set it up as you said first. If everything works well, stay there. If you can't clean up the motor at idle, go with more advance.
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  #59 (permalink)  
Old 12-19-2013, 09:54 PM
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The talk about the ignitions is interesting, I will have to do some reading on that. Realistically that is quite far away because this vehicle won't be running on the road till spring. I will have to pick a distributor before then though.

Back to carbs though, is there really any difference in brands? I like the holly carbs because it is a well known name and they make an adapter for their carbs to mount a TPS sensor. Any other brands that you suggest?

And as far a torque converter goes, so a 3000 stall lock up converter will lock up even if it is below the stall rating of the converter? The 4l60e has a .70 overdrive and the rear end is either a 3.73 or 3.83 (can't remember which), that means at 60 I would be doing only around 2000 rpm. Also does the lockup on stall converters operate just the like the stock converters or do you wire them up some other way?
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Old 12-19-2013, 11:44 PM
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Quote:
Originally Posted by L_C99 View Post
And as far a torque converter goes, so a 3000 stall lock up converter will lock up even if it is below the stall rating of the converter? The 4l60e has a .70 overdrive and the rear end is either a 3.73 or 3.83 (can't remember which), that means at 60 I would be doing only around 2000 rpm. Also does the lockup on stall converters operate just the like the stock converters or do you wire them up some other way?
Best to call and talk to the manufacturers before you pull the trigger on this.
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