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Desktop Dyno Guys!!! ATTN: Sled Dog

PhoenixZorn

PhoenixZorn

1/2 ton status
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Mar 17, 2005
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Location
West Allis, WI
Block - SB350A
Bore - 4.040"
Stroke - 3.48"
Piston & Rings - Speedpro Cast 8.5:1
Heads - Iron 76cc 1.94 intake 1.50 exhaust
Cam - Crane Cams High Energy 252*/258* duration @ .050" / .420 int/.420 exh lift 110* lobe center
Edelbrock Performer Intake Manifold - Off-Idle thru 5500 RPM

Engine tested with Quadrajet 750, headers and open exhaust.

I'm running a Holley 600, headers and glass packs.

Test results - 295hp @ 4500 and 380ft lbs @ 3000 per the engine shop.

Can you guys give me the results of Desktop Dyno on that stuff with both the Q-Jet and Holley? I still have the Q-Jet, so if it performs better than the Holley, I may switch it out considering it has electric choke, 150 more CFM and the Holley is manual and just "pretty"
 
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swap for the Qjet anyway. Definetally be better on power if its not junky(well rebuilt or just plain good to begin with).

DD2k says 279HP @ 4500 and 388ft-lbs @ 2000

Thats with GM 882 cylinder heads(pretty standard 76cc, 1.94 heads)
 
closed it out now but it was 381 at 3000 and something between 350 and 370 at 4000. Pretty damn good torque curver. In case you don't know its a 358 :D
 
Actually that was going to be my next question... what is my displacement?? =)

Ok... so what can I do about the sluggishness of my truck?? Other than having the 3.08 or 3.42 gearing changed to 4.11s... is there anything I can do to give it more "pep"??

Besides the carb, what can I change to get more horsies?? I wanna push 300hp without spending a fortune on new heads or pistons...

Also, isn't 8.5:1 compression pretty damn high, or is that just that the pistons are rated for? What was the compression with that setup?
 
gearing is gonna be your absolute best bet. I have 2.73s in my K5. It was a dog. The motor was strong and really torquey just couldn't do a think with those gears.

8.5:1 compression is not high. You probably run 87 or 89 pretty well. My 383 is 10:1, thats gonna be a bit high. Not sure if that 8.5:1 is rated for 76cc chambers(I'm pretty certain it is), if so then thats right, if not it could be as low as say 8:1 or high 7s. Many stock 350s are upwards of 8.5:1.
 
I can't even squak the tires in low if I pop the clutch... though offroad I can get them spinning pretty quicklike...

I do enjoy my 2400RPM at 65mph though... I may leave everything alone until I have another $2000 to spend on tires and new gears.

My question about the compression was what the DD2k said I should have for compression... just because pistons are rated for 8.5:1 doesn't mean that's what the compression is, does it?

To keep my RPMs at highway speeds at or below 2500rpm (for economy reasons) what is the best gearing for 35inch BFG A/Ts?
 
4.10s with 35s would run you about 2558 RPMs at 65mph

Not even squaking the tires is odd. My K5 would roast them(err one....) when I dropped the clutch in low. Heck all I had to do was tap the breaks and jump on the gas and she would sit still. Took a little more effort when the rear was welded.

just to note, I really don't like being the only one weighing in on this, I just do it cause I love engines and want to help with the knowledge I have.
 
Well... after tonight, I'll be weighing in on these questions... installing Windows shortly and will install DD2k as well. =)

My warranty SUCKS!!! check this out

Does not cover:
Damage due to accident, improper installation, negligence, alteration
Loss of time
Loss of income or revenue
Los of transportation or vehicle rental
Any towing charges
Crankshaft Thrust damage
Diagnostic time, fluids, filters or shop supplies
Oil starvation for any reason
Piston Scuffing
Overheating, melting of heat tab
Detonation, pre-ignition (melting of pistons)
Head gasket with burnt fire ring
Abnormal wear from contaminated oil (fuel dirt)
Equipment rental
Loss of time, inconvenience, or other economic loss....


What the hell else is there to go wrong? I mean the way it looks, the only way I can get anything covered by the warranty is if I throw a rod....
 
Ummmmm, a cam disintegrating, knocking (if they can't prove it is from oil starvation), timing gears disintegrating (it happens), broken rocker arm, bent pushrod, failed lifter, etc. It covers tons of stuff and pretty much everything they mention is stuff that you would make fail.
 
i'll bite... i would seriously look into the Comp Xtreme Energy XE-256. i know several guys running this cam, with almost 9:1 compression, and on mid grade gas to boot. the torque curve is almost flat from just off idle to over 4000, also above 400 ft/lb. peak hp is 330 @ 5000, peak tq is 414 between 2500-3000. couple that with a set of 4.10 gears, and a set of 35s, and you're golden. the 8.5:1 CR is a little on the low side for anything with a cam around that size. it'll run good if you're running swamp water, but 87 octane is even to high for a compression ratio that low, if 87 is the lowest octane you can get might as well build for a little more power.
 
Ok... here's a new question... Sled dog, the numbers you gave above, is that for holley 600 or q-jet 750? I only ask because if you ran the holley and got those numbers, I shouldn't switch out the carb (except for the obvious trail reliability of the Q-Jet in it's natural form) What are the numbers with both carbs?

I didn't get a chance to install windows last night, so I don't have DD2k yet...

The problem with me changing internal parts is that it voids my warranty... the only way I could do that is if I actually drove to denver and into the shop to have them do it, and for a $150.00 cam replacement, the fuel cost ratio just isn't worth it. If however I break something, I will surely have them upgrade the cam...
 
Are those heads you already have? if your budget can afford it i would consider looking into some Gm vortec heads, you won't need to do anything special to them to work with that cam lift. i picked up a pair off ebay for 300 bucks. for that you get a much better head. more power, better fuel effeciency, you can run more compression with out worrying about detonation=more power. those heads on my 406 put out(on a real dyno) 400 h.p. and 470 ftlbs with 9:1 compression. over 400 ftlbs from 2000 on up.

--Scott
 
like he said, change something of the motor, bye bye warranty.

I ran with the 600. Just my recommendation to go back to the Qjet.
 
Other than the obvious better trail ability out of the box of the Q-Jet, why else should I change it over? If I put the fuel rail across the bowls on the Holley, it will in essence be a Truck avenger... I apparently get less hp (-15hp at the same RPM) with the Holley, but 8 more torque at 1000 less RPM than the QJet...

I will also get the same bogging I had when the Qjet was on the 327, that I don't get with the holley due to the larger primaries... what benefits will I get out of the QJet by switching...
 
Q-jets don't bog because of small primaries. If your carb was bogging at part throttle, you had it set up wrong. Q-jets can bog because they have vacuum secondaries and sometimes they fall out of adjustment and the secondaries come on too fast too soon and you end up with a lean condition and hence the bog. I don't know why anyone with a carbureted truck would run anything but a Q-jet, I promise it will outperform your carb in every way if you set it up right! :)
 
who wants to help me set it up right?? I'm about to go outside and clean it up... it's pretty nasty looking, no rust, but lots of road grime... I'll take pictures as I go...
 
600 Holley should be more likely to bog if the Qjet is setup right.

Like noted, it should not bog. Your secondary spring is probably too lose and they are opening too soon. Believe me, a properly functioning QJet is a real kick in the pants when the Secondaries open properly.

I'd switch cause you said the Holley is a manual carb. Did you mean choke or secondaries? Either way I'd consider switching. Qjet will get better offroad manners yes. Puting a dual feed on will not make it an Offroad carb. The offroad carb has a larger vent tube that goes up and over the carb more(so you aren't splashing fuel out) and has spring loaded needle and seats so they aren't bouncing out and flooding your engine. Definetally a different beast.

SOrry but I absolutely can't explain how to adjust the spring on the secondaries of a Qjet. I tried explaining it to my dad once and gave up, I just did it for him. I learned by watching someone else do it.
 
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