Wide open won't accelerate

[53 stickfigure]

Im normally not the guy that stomps on the gas at take off but i did today and im not happy. I can get in the truck and about 1/2 to 3/4 throttle and snap my neck on take off but mashing it down just slowly accelerates. It dont stumble, just dont have any wide open power. Its a sbc 383, edelbrock 600, holley street dominator intake, headers, electric pump regulated to 5 psi, crane 286 roller cam and 373 gears. I changed the plugs when i got it and after about 400 miles still look brand new. 3/4 throttle and it just keeps accelerating, scary fast, but give it just alittle more and it slows down. It has a jegs transmission with no kickdown but even downshifting then full throttle loses power. Ive never owned or built an engine that has done this before. No miss, runs great with plenty of power up to 3/4 throttle. I haven't messed with the timing yet because it starts so easy, even hot. Anyone else ever ran into this?

 

[Sam_Fear]

I still stumble through this stuff myself, but I'll get the conversation rolling. Sounds to me like you maxed out your fuel at 3/4 throttle and any more than that you're just adding air. Bigger jets or more fuel pressure? ....or I don't have a clue what I'm talking about.

 

[Old Iron]

I had the exact same thing happen to me on a 327 with HEI distributor. Turned out the distributor was bad so I changed it out and no more trouble [P[P[P

 

[53 stickfigure]

I messed around with the timing last night and didnt change a thing. I have a cheap mr gasket fuel regulator. I think i will get a fuel pressure gauge today just to see the exact pressure.

 

[sneakysnake]

Sounds like when the secondary opens your starving out. I'd take apart check float and jets.

 

[Blue Eyed Devil]

Take that Mr. Gasket regulator off and throw it as far away from your vehicle as possible - JUNK.

Put a good Holley regulator on it with a gauge, and at least that issue will be eliminated.

 

[kenny c]

sounds like a lean condition when secondaries open. take the air cleaner off and check that they are spraying when wacking the throttle wide open.

 

[Bamamav]

Had a Ford pickup with a 351W that would do that, never did figure it out. Ran great unless you held it down, you could hear the secondaries on the Ford Holley open up, then it got slower instead of faster. Put the same carb on a 302 later on, it ran great.....Fixed the truck by putting a 2 barrel on it. I guess the carb was too small, but it came factory on the truck. The 2 barrel worked the same all the time.

 

[Dr Crankenstein]

I messed around with the timing last night and didnt change a thing. I have a cheap mr gasket fuel regulator. I think i will get a fuel pressure gauge today just to see the exact pressure.

Pressure at idle (or, whacked wide open on the driveway) can't tell you what you really have.

Put the gauge where you can see it. Drive it. You need a minimum of 2 lbs. at WOT, 6 lbs. maximum everywhere else...

.

 

[53 stickfigure]

I was leaning towards a lean condition by looking at the plugs being so clean. Id feel more at ease with a richer mix. I ran a 302 years ago way too lean and burnt a hole in a piston. Ive been staying off the gas till i figure this out. Im really considering a holley also, I prefer things im familiar with.

 

[Sam_Fear]

How about more info.

Is that carb new or used? Have you gone through it? Is it set up stock? What size jets?

 

[53 stickfigure]

Carb is brand new, but i have no idea if anything has been done to it. I just ordered a new holley regulator and fuel pressure gauge. I dont know anything about the edelbrock carb but i found the dvd it came with in the receipt box the guy gave me with the truck. Im going to change the inline fuel filters today and take the cool can off, I'll never put ice in it anyway, just to see if it helps.