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Discussion Starter · #1 · (Edited)
If you've followd along with my "progress" with a 383 in a 95' Silverado you're well aware i've spent some time researching a learning the performance side of building/fixing cars. 350 to 355 to 383 to supercharged 383. Learned something with every engine and every set up. I feel like, with a lot of help from y'all, google, and some books, i've got a decent grasp on what's going on to make horsepower.

The current 383 (really a 385) is a 8.5:1 pump gas 93 with a progressive meth injection set up and a Weiand 177. Running a locked distributor at 30 degrees running on a MSD 6AL and 7-8 psi by redline. These are out of the box Promaxx 200 series heads with a crower hydraulic roller. Cam is a 236/240 .555/.559 on a 110 LSA installed at a 106 intake centerline. Transmission is an AR5 5 speed out of a Colorado. Yukon limited slip 3.73 gears. Caltrac's installed with some Nitto street radials. 1 5/8" longtube headers ran straight out the back with no cats and just two mufflers. Pipes are 2.5"

Using a dragy, the best 1/4 mile time i've gotten is 12.8 at 110 mph. The truck weighs right at 4,000lbs. Using a generic HP calculator that would estimate the RWHP right at 400-410hp. Using the very generic 15% powertrain loss that would mean about 475 at the flywheel.

I just see so many 383's NA making 450-500 power at the flywheel.I just can't see how i'm only making the same running a meth set up and a Weiand 177 at 7-8psi?? Can it all be in the cylinder heads?

I was really hoping for 550-600 and to be able to dip into the 11’s.
 

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Well you're into a lot of complications.

- 15% installed power loss from crankshaft to where the rubber meets the road is highly optimistic. This is getting in the range of pro builders that lose sleep, grow ulcers, have near university or OEM level test facilities and spend millions of dollars. Back in my Ford test cell days fresh out of college it was typical to see 40 to 50% power difference between crankshaft dyno and chassis output. So these chassis dyno guys grab this optimum NASA style data reductions to apply everywhere. Best I can say is your experience might be different. The best way to test engine crankshaft power is to take it out of the truck then deliver it to someone with an engine dyno for testing. Here again you’ll run into a set of rules for testing where the engine is warmed to about 160 degrees F including the oil and spun up against a load that limits the WOT crankshaft acceleration speed to 300 RPM per second. Change the parameters and you get different answers. Then the answers you do get are adjusted for a standard air density day so the numbers you see on TV shows have a lot of fudge factors in them between the crankshaft flange and the flat panel readout.

- Heads, yes the heads have a huge impact a high end set of domestic heads will out perform a well prepared set of imports by 80 or more horsepower.

- Your approaching the point where there are so many issues.
**It takes huge power increases to gain but fractions of time and trap speed increases.
**Hook is a huge factor and getting and keeping hook gets into not only tires but on into drive line deflections and chassis reactions in twist across tge width and bending in the length of the vehicle and on into suspension reactions. In the end it’s the horsepower calculated from vehicle weight and speed through the length of track being run. The mid time intercpvalls are important as well like the 60 foot not only shows how consistent you are to the green light launch but also how well the chassis is reacting to the shock loads imposed on it.

- An important calculation is comparing your time slip data converted to horsepower to the chassis dyno test horsepower. This will tell you a lot of how well the chassis is putting that power to work. The other great info piece is off a crankshaft dyno compared to the chassis this separates out any nonsense about chassis to crankshaft relationships for your specific vehicle.

Bogie
 

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I think you have a few things working againest you.
The weight of the truck for one but the biggest roadblock I see are the head's and small size of the header's.
If you think of the engine as an air pump then you can see that no matter how big a blower you put on it the engine will only flow so much air and anything more is just wasted.
I think the pro comp's are basicly a small block old design head, Fine for a NA car in a daily driver but not really a preformance car.
You might want to research some new head's and header's and contact your cam company for a custom grind or better yet find a cam designer.
Another concern is the carb or carb's or EFI.
I might have missed it but no mention of what you are running.
As to the 15% drivetrain loss you can't go with that as I have seen up to a 40% loss on some combo's.
Good luck
Greg
 

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Discussion Starter · #4 ·
Well you're into a lot of complications.

- 15% installed power loss from crankshaft to where the rubber meets the road is highly optimistic. This is getting in the range of pro builders that lose sleep, grow ulcers, have near university or OEM level test facilities and spend millions of dollars. Back in my Ford test cell days fresh out of college it was typical to see 40 to 50% power difference between crankshaft dyno and chassis output. So these chassis dyno guys grab this optimum NASA style data reductions to apply everywhere. Best I can say is your experience might be different. The best way to test engine crankshaft power is to take it out of the truck then deliver it to someone with an engine dyno for testing. Here again you’ll run into a set of rules for testing where the engine is warmed to about 160 degrees F including the oil and spun up against a load that limits the WOT crankshaft acceleration speed to 300 RPM per second. Change the parameters and you get different answers. Then the answers you do get are adjusted for a standard air density day so the numbers you see on TV shows have a lot of fudge factors in them between the crankshaft flange and the flat panel readout.

- Heads, yes the heads have a huge impact a high end set of domestic heads will out perform a well prepared set of imports by 80 or more horsepower.

- Your approaching the point where there are so many issues.
**It takes huge power increases to gain but fractions of time and trap speed increases.
**Hook is a huge factor and getting and keeping hook gets into not only tires but on into drive line deflections and chassis reactions in twist across tge width and bending in the length of the vehicle and on into suspension reactions. In the end it’s the horsepower calculated from vehicle weight and speed through the length of track being run. The mid time intercpvalls are important as well like the 60 foot not only shows how consistent you are to the green light launch but also how well the chassis is reacting to the shock loads imposed on it.

- An important calculation is comparing your time slip data converted to horsepower to the chassis dyno test horsepower. This will tell you a lot of how well the chassis is putting that power to work. The other great info piece is off a crankshaft dyno compared to the chassis this separates out any nonsense about chassis to crankshaft relationships for your specific vehicle.

Bogie
As always, a wealth of knowledge that blows me away. In the regard to chassis output vs crankshaft power, what bothers me about this is seeing a bunch of small block guys and LS alike with n/a motors running as good or better than me on the same chassis and similar set ups. Similar 0-60 times, similar 60 foot times, similar mph etc. but out of an N/A 5.3 that can't be making more than 400ish to the crank as an example. I know the LS is another animal but no way a bolt on 5.3 should be getting similar trap speed's as a supercharged 383? That's what holds me up in regards to believing it is just a chassis/drivetrain loss.

I know the heads need some help, and maybe thats where all the power is stuck.
 

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Discussion Starter · #5 · (Edited)
I think you have a few things working againest you.
The weight of the truck for one but the biggest roadblock I see are the head's and small size of the header's.
If you think of the engine as an air pump then you can see that no matter how big a blower you put on it the engine will only flow so much air and anything more is just wasted.
I think the pro comp's are basicly a small block old design head, Fine for a NA car in a daily driver but not really a preformance car.
You might want to research some new head's and header's and contact your cam company for a custom grind or better yet find a cam designer.
Another concern is the carb or carb's or EFI.
I might have missed it but no mention of what you are running.
As to the 15% drivetrain loss you can't go with that as I have seen up to a 40% loss on some combo's.
Good luck
Greg
Yea, its a pig at 4,000lbs. But that goes back to the previous reply I gave to Bogie. Same trucks, similar set ups have run as goood N/A and some bolt on 5.3 running about the same also. I've seen a lot of 5.3 bolt on dyno's. Even the really well built ones are 425ish to the flywheel. I just have a hard time understanding why a supercharged 383 would be making less than 500? I mean, I can only go off of trap times/speeds of the same trucks running combos I know don't make more than 425ish to the crank to assume that I have similar hurtles to clear as they do. I mean if we estimate even a 30 percent drivetrain loss with the chassis, that would mean the 5.3's im seeing with similar 1/4 mile trap speeds over 500 at the crank. I just haven't seen any bolt on N/A 5.3's make that much power.

It is a single carb. AED "blower" 850 carb. I think the cam could have a little better spec for the application, but I asked around at a few custom cam companies for their recommendations. All were pretty similar other than one or two recommended a 112 lsa.
 

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I will not go into all the diffrences between a LS and a SBC.

But let me say that a LS can adjust the tune faster staying within a tighter window for the track that day, temperature, elevation, moisture, etc. Both of the small block and the LS may make similar numbers (lets say a nice round 500hp) in the same dyno with everything set up for that day and such. But when you take that small block and raise it up 1000 feet and go from say 65 degree dyno room to 95 degrees at the track then add in many other factors. Unless you know (and adjust the tune for) all those factors like the LS can and does then the LS is going to look like it is making more power.

The reality is the LS is not making more power your making less. This is because one of those several changes were not accounted for.

My main 3 reasons why I like a LS much more then any small block are Availability, it being built to handle power, and how simple the fuel injection is to swap and tune.
That last one is a big deal. You can have the "best" parts made from unobtainium and 4 or more times into your engine then the next guy. But unless you tune for those parts keeping everything working together you may find yourself looking at the other guys taillights.


So the short version above is you need to tune your engine.
Then once your engine is tuned you need to tune your transmission and rear end.
There is a reason why 2 speeds are still used. Consistency is a big deal. Someone may have a entirely different setup for a 60 foot then a 1/8 or 1/4 mile.

The transmission and rear end aside we get into the suspension. Same deal here what worked that one day at that one temp on that one surface will be turned on it's head at "this" track even from one lane to the other. You need to tune that. The best way I know tuning the suspension is to get video from both sides comparing how one side reacts to the other and what the chassis etc is doing. If you have say the passenger rear squatting a bit more then the drivers rear and that causing the tire to loose traction(additional wrinkles in the sidewall making a jarring motion as it grips then slips then grips) and at the same time the drivers tire is raised into the air suggesting many things. Then you need to look at the cause and tune for it. Wheel stands look cool to kids. But a car that can have those front tires kissing the pavement on launch and keeping that suspension from becoming upset looks much cooler to me.


I myself like a soft rear end. Something that squats just right then you can fine tune with shocks. A soft long travel front end that will keep those tires planted and lessen shock loads. This is not a power thing. I can have a rwd 250hp car outperform a rwd 500hp car in the 60 if I am allowed to play with both of them. Watch which one makes more smoke and which one makes more traction.


Now we get to weight. I weighed my standard cab short box 96 1500 with a 5.0, nv3500, and 10 bolt. 5060lbs w full tank. That is with nothing done to it. Totally stock. Now depending on the rules in the class there are things you can do and can't do.

Weight reduction is a game of ounces not pounds(even though pounds are used below for general reference).

Let me just give you a few things to remove or modify as long as what you replace them with stays within the rules. Figuring standard cab short bed
Front and rear bumpers(replace with lighter)200lbs
Side fuel tank(small rear mounted tank potentially offset to passenger side slightly) 60lbs
Washer pump(delete) 2lbs
Aluminum accessories 4lbs
Inner fenders(delete entirely) 2lbs
Modify fenders(skin interior bracing) 3lbs
Modify front clip(reduce bracing) 3lbs
Modify hood(reduce bracing) 2lbs
Rear mounted 46B2 size (around 410cca) battery(25lbs and only cost around $250) 20lbs
Interior sound deadening including that heavy rubber mat gone 12lbs
Radio and speakers delete 3lbs
If you have crank windows you can gut/remove the crank mechanism 8lbs
Dash HVAC delete (ducting, controls, motors, including all ac components) 40lbs
going to stop here. That is 359lbs of easy to remove weight.

I did not even get into the suspension, frame, and the truck still looks stock with the factory doors, dash, etc all in place. You can also move weight around. A rear mounted radiator will often gain you a few pounds in total weight due to the lines required. But a majority of that weight will be moved to the rear and better used. Also because you have those lines your often increasing capacity which may allow for a smaller radiator to be used. Most guys will run 1" flexible line(or an-20) I prefer to run 1 1/2" solid lines as those solid lines shed heat and don't sag or require expensive connections. Normal radiator hose can be used with a rolled edge and t clamps. Check your rules. .

Temp is in the 70's. Time for me to get away from this keyboard. You have some homework to play with.
 

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a low compression NA 383 with those heads would make 350hp. the 7-8 pounds of boost should add 150hp.
what does the AFR look like?
can you change pulleys and make more boost?
cam needs a wider lobe separation and more exhaust duration to be drag race friendly
 

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Discussion Starter · #8 ·
Well, doing some checking on the ole set up and realized the timing changes every time I rev the engine lol. This is a MSD 6AL box with a summit magnetic pick up distributor. Locked out.

I check the timing initially and it read 40 something degrees! So, as confused as I was I set it back down to 32. Revved the engine again and read 12 degrees. Revved it again and it was 20 something. Again, back to 40 something. Again, back to 32ish

Engine seemed to be running the same each time. This is a pretty new summit balancer. I can only assume it’s moving? If there was a 20-30 degree timing change it idle I’d think the motor would change too.

I guess I have no idea what timing I’m really running? Lol what’s the easiest way to check the balancer?
 

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Bring #1 cly to tdc on the compression stroke. One way is to set a dial indicater on the tip of your valve to check total lift. look at balancer and see if 0 is within tolerence.
This isn't exact but if your balancer is correct it should read the same on each rotation of the engine.
I like to do at least 2 rotation's of the crank to be sure.
Greg
 

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Sorry had some company come over when typing. What I was trying to say is bring your clyinder to tdc with both valve's closed. No need for the dial indicater.
Greg
 

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Paint a line with a paint pen or sharpie or finger nail polish, along the damper mark and down the front to the hub. It's a reference mark. If the hub moves, the lines won't line up.
I suspect you have some lash issues with the dist and cam gear interface OR dist end play OR the dist gear drive pin is broken.
Perhaps your timing light is too quick and picking up one or both of the multiple sparks below 3000ish. use an older crappy one.
 

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Dragy on the street?
My 3960 pound truck can't hook on the street no matter what.
One thing you really need to know is your 60ft on a prepped track with your drag radials. Go around the water box.
Temple has a good track. San Antone is not far either, and they run street cars almost every Friday and Saturday night.
That being said, you will probably do better than high 12s if you are hitting 110 on the big end now. It makes a lot of sense what my machine shop told me. "It seems like anytime you put a hot motor in a pickup truck it loses 100 horsepower right off the bat."
Think of those big long frame rails as pieces of spaghetti just soaking up horse power!
Bogey nailed it when he was talking about driveline losses.
With my truck I have come to accept the fact that unless I go into a dyno cell with my engine, i will never know what it makes. But I got 12.6 at the track and 105 mph with a 1.80 60ft. so that's good enough for me right now.
People say that's really good for a small block in a heavy ass truck!
 

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Discussion Starter · #13 ·
Paint a line with a paint pen or sharpie or finger nail polish, along the damper mark and down the front to the hub. It's a reference mark. If the hub moves, the lines won't line up.
I suspect you have some lash issues with the dist and cam gear interface OR dist end play OR the dist gear drive pin is broken.
Perhaps your timing light is too quick and picking up one or both of the multiple sparks below 3000ish. use an older crappy one.
Duh! Definitely an easy way to check the balancer. Thanks. This distributor has always felt crappy. It’s summits house brand. I wouldn’t be surprised if it’s an issue with it. I’m using a newer, but cheap, Innova timing light with no dial back adjustments at all on it.
 

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Discussion Starter · #14 · (Edited)
Can y’all tell where the timing mark is from these pictures? All four are a picture of the same plug.

Additionally, if the problem is lash in the distributor, distributor end play, or a broken pin, is it actually screwing with the timing?
 

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your mph vs et is way off
110 mph should be 12.0s on good tires
so either you spin on launch and make no top end charge or spin mid track?
Not making much power. Factor out the blower its maybe 340 hp?
Intake valve closes too soon
headers way too small.
Maybe the launch is too gentle or maybe you eat a sandwich between gear changes?
Put up a video
My old car ran 11.9s @110, I figure it was 390 hp
 

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Telling timing mark from plug color is that what your asking?

My impression is the plug looks pretty good the insulator is a tannish color which hints that for how the engine is driven the heat range is in the hood. The plug is not carboned up so the mixture ratio isn’t rich, or isn’t wet so it’s not drowned in fuel. The insulator isn’t oily so it isn’t pulling any abnormal amounts of oil into the chamber, also shows the valves are opening enough so the lifter and cam lobes aren’t lunched. It isn’t stark white that is typical of a lean mixture or too hot a temp range or excessive advance.

Some oil on the gasket but that can be some external oil leakage that got into the plug dish on the outside. The threaded steel body is a bit grungy but that’s expected as the threads are transferring hear into the head so this is typically a chilly spot compared to the rest of the chamber.

So I’m not seeing anything that looks out of line with what I’d expect to see.

Bogie
 

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Alignment can kill a lot of mph, also a lot of rpm drop in those AR5 1/2 and 2/3 spreads. Are the 5.3 guys you are comparing your setup to running the same trans?

Grant
 

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Discussion Starter · #18 ·
Dragy on the street?
My 3960 pound truck can't hook on the street no matter what.
One thing you really need to know is your 60ft on a prepped track with your drag radials. Go around the water box.
Temple has a good track. San Antone is not far either, and they run street cars almost every Friday and Saturday night.
That being said, you will probably do better than high 12s if you are hitting 110 on the big end now. It makes a lot of sense what my machine shop told me. "It seems like anytime you put a hot motor in a pickup truck it loses 100 horsepower right off the bat."
Think of those big long frame rails as pieces of spaghetti just soaking up horse power!
Bogey nailed it when he was talking about driveline losses.
With my truck I have come to accept the fact that unless I go into a dyno cell with my engine, i will never know what it makes. But I got 12.6 at the track and 105 mph with a 1.80 60ft. so that's good enough for me right now.
People say that's really good for a small block in a heavy ass truck!
The harmonic balancer is spinning. I put a mark on the blower pulley attached to the center of the balancer, then put a mark lining up with it on the outer ring of the balancer. The outer ring is moving, and its moving quite a bit. I mean it will make it look like the timing is 13 degrees and then a couple revs later it looks like its almost 50!

Anything wrong with just a factory style balancer? The rotating assembly was not balanced with it. Is a more inxpensive balancer worth the money? I'm only spinning it to 6k rpm.
 
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