Opinions help with combo

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Opinions help with combo

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Chevrolet >> Brand Review >> Engine & Internal >> Opinions help with combo

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Opinions help with combo - 1/23/2008 1:53:15 PM

Vettes82

Posts: 2
Joined: 1/22/2008
Status: offline

Looking for opinions and insight. I just built a 10-1 .040 over 4 bolt 350 with a balanced scat rotating assembly, kb flattops, new Brodix IK180 heads, compcams x4254H cam, roller rockers, gear drive, Weiand xcelerator dual plane intake, edelbrock 600 cfm carb,hei w/65k coil and block hugger headers connected to new 2.5 inch exhaust with flowmaster 50 series mufflers, a new 350 built tranny a new converter with 2000 rpm stahl, 3.42 gears. I have played with timing and it seems to run best with 14 initial and 36 total. My issue is I was expecting about 350 horse from this motor and it appears to only be making 280-300. Desktop dyno rated it at 375hp. The motor runs good, is responsive and is strong so I am confused as to why my power is so low. I think my combination should work well together but it just doesn't seem like it has the horsepower it should have. Are my expectations incorrect or is there wrong with my combo. This is a daily driver car and is not wasn't built for racing.

Post #: 1

RE: Opinions help with combo - 1/26/2008 12:04:30 PM

dgulian

Posts: 10
Joined: 1/26/2008
Status: offline

the 14 timing seems high to me. I usually run 6 to 8 and max out at 32 at 2500 rpm.
http://s217.photobucket.com/albums/cc25/dgulian/
there is a picture of the engine It runs real strong and does use alot of rear tires, I am trying to fix that.

(in reply to Vettes82)

Post #: 2

RE: Opinions help with combo - 2/24/2008 7:27:15 PM

House

Posts: 5
Joined: 2/19/2008
Status: offline

I am a little confused as to what you mean when you say "appears to be making only 280-300."
I mean, is that what the car did at a dyno shop, measured at the rear wheels? if so that sounds pretty good to me. Are you saying you can just feel that there's 280-300 Horses? if so that's impressive. i mean, that sounds like a pretty solid motor. It's got to sound great, too.

(in reply to Vettes82)

Post #: 3

RE: Opinions help with combo - 2/29/2008 1:02:00 PM

mudmaniac

Posts: 40
Joined: 1/22/2008
Status: offline

My thought are the carb.
600 cfm sounds like it my be chocking down the performance.

_____________________________

MudManiac
95 Tahoe 383cu.in./350hp/425ftlbs
6" lift 16x35x16 Boggers

(in reply to Vettes82)

Post #: 4

RE: Opinions help with combo - 4/19/2008 1:13:11 PM

javelin350

Posts: 10
Joined: 4/19/2008
Status: offline

My thought too, on small carb. how is the fuel delivey system? and what octane gas on that high comp motor?

(in reply to Vettes82)

Post #: 5

RE: Opinions help with combo - 5/28/2008 4:24:28 AM

1Gary

Posts: 24
Joined: 5/24/2008
Status: offline

Not a real fan of desktop dyno's here.They all suppose perfit condisions like weather,air etc.That's is not what real street is like.For over 20yrs we have had a drag racing team.Many cars during that time.We use a weather station and keep a record of the tunes we have done vs the changes we have in the weather condisions and the results we found.If you take your ride to the local drag strip and test and tune there,it more real to the torque and hp you are making.You should remember that e.t. is more the results of torque and mph is more the results of hp.I think torque is more of what you want on the street becuase it is more in the normal lower rpm ranges of street driving vs hp which generally is in the higher rpm ranges not used normally in day to day driving.

This comes also from 5 yrs in the Chevy Tonn,NY plant yrs ago as a engine tester and tester in the dyno the room there as well when I worked there.

(in reply to javelin350)

Post #: 6

RE: Opinions help with combo - 6/17/2008 7:39:29 AM

BurninRubber92

Posts: 23
Joined: 6/16/2008
Status: offline

I agree with the others, it''s the carb. I suggest upping to a 700cfm, and tuning that carb. perhaps jet it, and if it has vacuum secondaries, change the vacuum spring to get all 4 bbls open earlier. 300hp seems too low for the setup you''ve got.

Have you had it professionally dyno''d?

(in reply to 1Gary)

Post #: 7