70shortwide

iTrader: (6)

so i finally got my truck to the point that i can beat on it and its a dog compared to what you guys say these motors can do. I dont have any prior experience with LS motors so im kinda a newb. Here is what I got:

LS6 with TEA stage 2.5 heads
EPS 230/238 .600/.603 112+3 cam
1 3/4 headers with dual 3" exhaust
Vic Jr. intake
950hp carb
4000 stall converter
I have timing set to ramp to 32 at 4000 and 36 at 6000 then flat

when i stand on it from stand still it goes but just not alot of power, doesnt even light the tires. I hooked up trans break and set 2 step to 4000 and when I let go of the button it barely spun and bogged down to about 2500 before it started to rev back up. If this is all it will do im going back to BBC. Any ideas would be great. Thanks.

HELP!!!!

ZONES89RS

iTrader: (25)

Carb is too big and possibly not dialed in. Should cook the tires.

GC99TA

iTrader: (30)

Who installed the cam? Were the valve events verified with a degree wheel? Is it possible it's off a tooth? Should make a lot more power than you're describing.

cammedv

should make well over 425 wheel hp with those mods so something isnt right

1994z

iTrader: (48)

x2 on carb.

pairof69s

dumb? but what rear gear.....

70shortwide

iTrader: (6)

I built the motor and instaled the cam dot to dot. Unfortunately this carb is all i got for now till i can trade for an 850. The rear gear is 4.11. Thanks for the response. I think i know where a 750 is i can try to see if it makesa diff.

Prorac1

iTrader: (4)

There is a GOOD chance that the cam is not installed where it is suppose to be. The last two cam installs we've installed, (1 LT1 and 1 LS1, and both were custom grinds by good name grinders) were both off in reguards to the intake centerline method. I would degree the cam and see where the intake centerline REALLY is. Hope this helps, Eric L

speedtigger

iTrader: (16)

I disagree that your carburetor is too big. The Holley 950 HP is little more than a 750 HP with an 850 baseplate. You can use the HP 950 pretty much in place of the 750 without consideration. this is why they made the 1000 HP.

I would start with checking to see if you are getting wide open throttle at the carb when depresing the gas pedal. Then a cranking compression test.

Prorac1

iTrader: (4)

ARGHHHHH, damn you Speedtigger, lol. I always overlook the obvious.

Ok, check for full throttle, than check cam degreeing, yeah, thats it, lol. And I agree, there is nothing wrong with the carb size, espically with the 4.10 gears. Eric L

70shortwide

iTrader: (6)

i kinda think its a cam issue as well. its getting exhaust done today and im going to try to take to track on friday if its not raining. if i can take to track and see how it does on mph that might help me figure out what the problem is. but it sounds like im going to learn how to degree a cam lol

70shortwide

iTrader: (6)

hahaha yea its getting full throttle (had that happen before)

ZONES89RS

iTrader: (25)

Don't care if you guys think the carb is ok, just know it would run better with a 750. Lol

Prorac1

iTrader: (4)

I agree Zone. Throttle response and driveability would probably improve with a smaller carb, but I dont think thats why his trucks a turd, lol. Eric L

ZONES89RS

iTrader: (25)

I don't either, just a opinion.

topbrent

iTrader: (1)

That engine has great parts and a good overall combination. It should be a very capable performer once you get this figured out.

A few things to check out:

Compression test?

Bad gas?

Vacuum leak?

Obstruction in carb or fuel line? ie, plugged jet or passage.

Accelerator pump working properly?

Air Fuel ratio?

Fuel pressure?

Fouled plugs / plug gap?

Faulty plug wires?

Faulty coils?

Faulty MSD box?

Good 12V feed Voltage to MSD Box?

Already stated...cam installed correctly?


The 950hp is a great carb, and solid concept. However, calling it a 950 is a deceptive marketing ploy by Holley and the myth/lie just keeps being perpetuated....they flow about 870 on a good bench and have about the same basic throttle response as a 750. It is a 750 bore size with a 850 sized throttle plate. Great velocity is maintained due to the 750 main body and you pickup up the extra CFM with the larger 850 sized butterfly's.

tennerv8

iTrader: (7)

Wow something is wrong. With mine running shitty it will destroy the tires at most speeds. I would check for wot.

streetknight2

iTrader: (10)

I had a 1050 on mine, switched to a pro systems 950 which flows 840 on a bench picked it up a lot.

When I talked with Holley they told me the HP series were the only carbs that actually flowed what they were called.

As far as OP, I would agree on degree cam

orange88ls1s-dime

I have a 390cfm Braswell on my 5.3L s10 works great, shows you dont need to over carb an engine to get it to perform. can do 3rd gear burnouts for like 300 feet pretty effortless and my engine is right out of an 05 sierra all I did was put carb setup and sanderson S10 headers on.
Beaudacious

speedtigger

iTrader: (16)

And the truth shall set you free.....