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Proven Combo....Seems slow
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RaG
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Joined: 20 Dec 2002
Posts: 85

296.96 points



PostPosted: Tue Dec 16, 2003 1:30 am    Post subject: Proven Combo....Seems slow Reply with quote

I recently dropped in my new motor:
355
Vortec w/ 1.5 Rockers 10.1:1
Performer RPM AirGap w/ 600cfm Holley
XE 268 Cam, 224/230 @ 0.050
Th350 3.73 gears

After adjusting timing for optimal performance, feel wise (yea i know its not the best way). My car runs smooth, still some carb issues. Wants to die in idle, little stumble off idle, but those are small issues.

The motor seems pretty much no faster than my bone stock smogger 350 that i just removed. Doesn't really seem like 370-390 hp.

Maybe I can't really tell because i'm still trying to take it easy on the motor. Should 300 miles be sufficent before I start having some fun?

Would a Higher stall, 2000-2200rpm make the engine less likely to die in gear?

Hopefully it will pick up with a bigger carb. Think i'm only go with like a 670 street avenger since its a daily driver.
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Hanz
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Location: Casselberry, FL
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2003 Dodge Ram

PostPosted: Tue Dec 16, 2003 7:59 am    Post subject: Re: Proven Combo....Seems slow Reply with quote

RaG wrote:
I recently dropped in my new motor:
355
Vortec w/ 1.5 Rockers 10.1:1
Performer RPM AirGap w/ 600cfm Holley
XE 268 Cam, 224/230 @ 0.050
Th350 3.73 gears

After adjusting timing for optimal performance, feel wise (yea i know its not the best way). My car runs smooth, still some carb issues. Wants to die in idle, little stumble off idle, but those are small issues.

The motor seems pretty much no faster than my bone stock smogger 350 that i just removed. Doesn't really seem like 370-390 hp.

Maybe I can't really tell because i'm still trying to take it easy on the motor. Should 300 miles be sufficent before I start having some fun?

Would a Higher stall, 2000-2200rpm make the engine less likely to die in gear?

Hopefully it will pick up with a bigger carb. Think i'm only go with like a 670 street avenger since its a daily driver.


Sounds like you're having carb problems. With 3:73 gear you have absolutely no stumble off idle. And with that small of a cam, stock converter should work fine.

I installed a 351W last weekend with a 280 cam in it, and happened that the converter we had was wrong, so had to put the stocker back in. (Rough) idle but idled down to 700 fine, and with the 3:73 gear would burn the tires instantly off idle, say by 1500 rpms.

As far as playing with it, that sortof depends on the clearances it was built with. If was built with performance clearances, change the oil and go for it. If it was built with stock clearances, do an oil change and then gradually get into it over the next few hundred miles.

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RaG
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PostPosted: Tue Dec 16, 2003 9:18 am    Post subject: Reply with quote

Wow, I'm really looking for some decent power from this combo. Getting it built and into the engine bay has left me broke. I think i'm work up some cash in the next few weeks and get a 670 street avenger and see how it works. I'm just tired of looking @ this 4160 600cfm holley.

Where would I start tunning the current carb? Idle mixture screws seem to be set correctly.

I hope its between the carb and some slight tunning of the timing, I'm ready to roll =)
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jeep_406
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1972 Chevrolet Nova

PostPosted: Tue Dec 16, 2003 11:14 am    Post subject: Reply with quote

I don't mean any disrespect but you put all that money into a new engine and then set the timing by feel? Embarassed
Put a light on it.
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RaG
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PostPosted: Tue Dec 16, 2003 11:37 am    Post subject: Reply with quote

non taken

I set the initial to 10 BTDC, but since I cannot seem to keep the idle down low in park with out it dying, i think the rpms are bringing in the mech advance wich is not giving me a accurate reading of initial timing.

no tach yet, shop broke the motor in
geting everything in and built has left cash a little tight

1st time thing for me
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Hanz
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Location: Casselberry, FL
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2003 Dodge Ram

PostPosted: Tue Dec 16, 2003 1:01 pm    Post subject: Reply with quote

RaG wrote:
non taken

I set the initial to 10 BTDC, but since I cannot seem to keep the idle down low in park with out it dying, i think the rpms are bringing in the mech advance wich is not giving me a accurate reading of initial timing.

no tach yet, shop broke the motor in
geting everything in and built has left cash a little tight

1st time thing for me


Did you take that carb off the previous motor? If so it should run decent without any tuning, unless it sat for a couple months and the metering block gaskets dried up and distorted. If it was only for a couple days during the swap, then assume it's still good, and look elsewhere. The Performer intake was #7116, made for Vortec? Balancer is new or known good from the old motor?

I will disagree a little with 406's comment, sometimes when having timing problems and stumped, tuning by ear will eliminate unknown problems such as a slipped balancer or wrong cover, in other words not knowing for sure where your TDC is.[/i]

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SMOKEmUP
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1979 Chevrolet Camaro

PostPosted: Tue Dec 16, 2003 1:08 pm    Post subject: Reply with quote

Why didn't the shop set up the carb or timing?

If they broke the motor in they had to set up the carb and timing, right? How much did you have to adjust it from where they set it. Something doesn't sound right.

From magazine's I've read that combo should be good for at least 400HP or more.

Hanz makes a good point about known good parts. I would check the balancer to make sure TDC as reported by the balancer is in fact TDC according to the piston.
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RaG
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PostPosted: Tue Dec 16, 2003 1:20 pm    Post subject: Reply with quote

I adjusted it only a little. They did set it up, but they didn't really get into deatil with it.

They were more quick to blame it all on my torque converter being too tight. I believe its more carb than timing. He only adjusted the idle mix screws.

Cause when i picked up from shop, it ran fine, just doesn't seem optimal. Didn't idle at all in gear unless i gave it throttle. Which it still does. However with my little adjustments it will idle in gear without gas unless i come to a quick stop, then its definately gonna die. Still have to give it gas sometimes. Ive had a few cut offs at red lights. Definately doesn't feel near 400 hp.

What can i do to the carb, or should i be aiming for a better carb since i plan on getting someting bigger. But it sure would be nice to get this current carb tunned until i get more cash for a better carb like a 670 avenger or 750 vac sec
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RaG
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PostPosted: Tue Dec 16, 2003 1:40 pm    Post subject: Reply with quote

yes its the right intake, its for the vortec heads

carb is the same carb i rebuilt about 6 months ago, came off my pervious motor which i drove to the shop to get the new motor

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SMOKEmUP
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1979 Chevrolet Camaro

PostPosted: Tue Dec 16, 2003 2:29 pm    Post subject: Reply with quote

RaG wrote:
They were more quick to blame it all on my torque converter being too tight. I believe its more carb than timing. He only adjusted the idle mix screws.


That sounds fishy to me. Something doesn't sound right.

Did you re-use the harmonic balancer from your old motor?

I wouldn't be so hasty to blame the carb, although that could be problem. If the carb has a vaccuum leak.

Something to consider is taking the car to a chassis dyno. That way you can safely tune it using a wideband O2 sensor and see exactly how much power your car is making. (Plus a lot of them have tuning services and / or let you use their tools.)
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RaG
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PostPosted: Tue Dec 16, 2003 2:36 pm    Post subject: Reply with quote

New balancer. No used parts on this motor. Just a cleaned up distributor with new vacuum canister and advance weights/springs. It cam out my stock daily 350 that ran flawless.

I think a chaiss dyno/tune is next. Cause i dunoo what to do.

To clarify, they blamed the dying in gear and rough/want to cut off idle on a too tight stock TC
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2x4
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PostPosted: Tue Dec 16, 2003 4:34 pm    Post subject: Reply with quote

I agree, something is off.
What is your compression?
Did they install the cam "straight up" or degree it?
Checked your plugs (rich/lean)?
Gotta play with that timing curve a lot more too. I keep reading the Vortec heads dont require as much timing as "conventional heads" -the standard generic 38* total. I havent used them yet, thats just what I've heard.

The overall combo sounds solid, it should be a neck snapper with that small carb on it. You already know you need more converter in it. I really feel its all in the timing, probably not enough in the lower rpms.

FWIW, years ago I ran that cam in my Camaro with a bone stock, 8.5:1 350 with 882 heads, Performer intake & 650DP holley, 11" 2500 converter and (gasp) 2.41 gears. Managed to pull a 14.96ET out of it while it weighed almost 3800lbs. The Extreme cams seem to be designed for low compression motors, since the 268 doesnt have much overlap. You should be killing this and your not, something is wrong! Theres a lot more in it somewhere.
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Hanz
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2003 Dodge Ram

PostPosted: Tue Dec 16, 2003 4:53 pm    Post subject: Reply with quote

smokemup wrote:


From magazine's I've read that combo should be good for at least 400HP or more.



Are you sure about that Smokem? I'll admit right now that I don't get to read as much as I would like to since I am working 12 hours a day, and if someone dynoed that combo at over 400 HP I guess that's the proof, but I would never guess that you could make that HP with a 600cfm carb and that itty bitty bumpstick... Confused

RAG- if you have the ambition I would pull the timing cover, check the gear marks, and then advance it 4 degrees. That will help some with the hesitation, but I still say it's not the torque converter... Hanz

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RaG
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PostPosted: Tue Dec 16, 2003 4:54 pm    Post subject: Reply with quote

I need ask him how he degreed the cam.

Its gotta be in the timing, i just noticed the timing tape is on backwards!

MAybe the TDC mark isn't really TDC, ill have to check that like others have mentioned.

How will i know when i have added too much timing?
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Hanz
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2003 Dodge Ram

PostPosted: Tue Dec 16, 2003 5:13 pm    Post subject: Reply with quote

RaG wrote:
I need ask him how he degreed the cam.

Its gotta be in the timing, i just noticed the timing tape is on backwards!

MAybe the TDC mark isn't really TDC, ill have to check that like others have mentioned.

How will i know when i have added too much timing?


That's why I said that sometimes timing by 'feel' is an option.

Keep advancing it until it is hard to start, in other words the starter can just barely crank it. Then go back a very little, until it will crank. Go for a ride!

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