Is that what 330 HP feels like? pics.

[nicolas72gmc]

I recently installed a GM crate motor in my truck. I had to put the Vortec on hold for now. My uncle had this motor setting for a year after it was pulled out of a 72 nova. The best I can tell it has the Eldebrock Performer package on it. #1407 carb, performer rpm intake and cam. He was told it supposedly put out @ 330. I don't know if it is the 260 or 290 hp crate. It definately has a little lope to it, so I can tell it has a little bit of cam. The problem is I can't get the damn thing to hit right on the low end. I haven't started with mains and metering rods yet, but I think that is where the problem is. It stutters and then at about 1500 kicks like a mule. Has anyone got this set-up? Where should I tinker first. I already installed new MSD wires, and I checked for strong spark. Good 13 volt hot wire at the dist., etc. Timing is at 14 degrees. I just know I have driven several cars at 325 HP and it doesn't feel even close. I am just frustrated with it. Any help would be greatly appreciated.

[Shaky]

What transmission and rear gears?

[El Jay]

If it's been sitting for a year the accelerator pump could have dried out. I'd try replacing that 1st. It's an easy fix.

On a side note, I'd get rid of that glass fuel filter & replace it with s steel filter.
I'd hate to read a post about how your truck burned to the ground because the glass broke.

[nicolas72gmc]

Originally Posted by Shaky

What transmission and rear gears?

Shaky, I don't know what gearing it has, I thought about that too. I know at 70 it is clicking at 2900 rpm.

Originally Posted by El Jay

If it's been sitting for a year the accelerator pump could have dried out. I'd try replacing that 1st. It's an easy fix.

On a side note, I'd get rid of that glass fuel filter & replace it with s steel filter.
I'd hate to read a post about how your truck burned to the ground because the glass broke.

Thanks El Jay, I will do that. I wouldn't want to post that either.

[70rs/ss]

That low of rpm at 70 means a 3.08 or so gear, but still the stutter is more than likely and off idle lean spike, check the accelerator pump as El Jay said and you can also change the linkage to get a bigger shot of fuel when you gun it. By the way you mentioned new wires etc, did you make sure you advance is working, mechanical and vacuume?? In a heavy truck don't expect it to be a race car (so it isn't fair to compare 300+hp motors in cars you've driven to a truck, you are at least a thousand pounds heavier than a car!), and even if it did put out 330hp (I wouldn't believe it till I saw a dyno sheet?), but anyways it would have probably been 330hp at the crank which is about 250-260 at the tires, not a barn burner by any means, you want power go BBC, otherwise drive it and enjoy a free engine.


Check the stock hei and you may need to do a recurve on the advance, as the stumble is more than likely fuel delivery (lean spike) and timing, also do not put more than about 4psi of fuel pressure to that edelbrock it'll blow past the needle and seat and run pig rich. Looks like a sweet truck just get the timing and tune right and you'll have decently quick ride.

[chevy_mike]

Assuming nothing is wrong with the cam and the ring on the harmonic balancer has not sliped, so your timing is actually correct, my first thought would be a fuel issue. It could be junk in the carb, parts inside it dried up, even a fuel pump or gas tank pickup issue.

Heck, I have even seen HEI modules go bad and cause wierd problems.

[10pointgmc]

1407 is a 750cfm carb 330 horse cant handle that much fuel is my best guess id put a 650 on it and see what happens

[chevy_mike]

Originally Posted by 10pointgmc

1407 is a 750cfm carb 330 horse cant handle that much fuel is my best guess id put a 650 on it and see what happens

Good point. I remember my ZZ4 crate engine recommended a 650 (and the dyno number were done with). A 1406 (600 cfm) would be a better choice.

[nicolas72gmc]

I didn't think about the carb being too big. That would make sense. One thought, the quadrajet I had on the old 350 is basically a 750 cfm carb isn't it? It worked good.

[kgt]

its a vac sec. carb. the size is not the issue.

[nicolas72gmc]

I was just reading the owners manual for the carb (again) and it states that if the manual choke is not hooked up then it will need to be wired in the open position. Could this possibly be the problem? If the secondarys are not opening up?

[nicolas72gmc]

Nevermind I just checked the secondarys are opening up.

[packers05]

get that quadrajet modded by someone good and it will run the ass off that shiny one, smaller primarys make a cam with less vacuum street drive better.just went through same thing my dad read online how to make the quad work with common drill bits and a little labor what a difference

[wwotr]

I had the GM ZZ383/425 HP engine in my 67 C-10.
The Power was tremendos.
Unfortunatley it blew apart the Stock Turbo 350 Tranny and instead of putting in a 700R4, I had the 350 Customed out.
Never saw its full potential and had to sell it back in 2005.
I'm starting over with my 72 GMC Shortbed Fleetside.
Roger

[stllookn]

Call the Edelbrock Tech Hotline and give them the specs for your entire package and they can be very helpful.

[67ChevyRedneck]

330hp feels a lot different in a 3,000lb-ish car vs. a 4,000lb brick of a truck

[short-t]

Hi Nick, 14* initial timing is pretty conservative for a sbc, I'd try 18* and see if it helps. I was looking at the photo trying to see which hole the accelerator pump rod was in, if I had to guess it looks like the third hole in, If my guess is right than you are getting a full shot of the accelerator pump when you step on it. Try moving it to the middle hole for starters. But only after you set your timing to 18*.

[STINEY]

What is your total timing?

That's the number I'd be more concerned about. Get total in the 36-38 range and let the initial fall where it will.

I bet the total is way high. You'll have to verify that the timing marks are correct first. They are known to be off on occasion. Pop the valve cover, and turn it until #1 intake opens and closes. Then continue to turn it until the #1 piston is ALL the way at the top. (through spark plug hole to verify this)

Now look at the timing marks. Is TDC really TDC? If so you're good to go, set total timing to 36-38 at 3500-4000 rpm.

If not, fix those marks!

Good luck!

[tires2burn]

Check for low vacuum. I had a intake leak and it caused a bad hesitation on acceleration.

[Ackattack]

I had a problem where the mechanical advance had rusted together due to the humid winters here in WA. I doubt that is a problem in TX.

Sounds like a timing or fuel issue though.

[nicolas72gmc]

Originally Posted by short-t

Hi Nick, 14* initial timing is pretty conservative for a sbc, I'd try 18* and see if it helps. I was looking at the photo trying to see which hole the accelerator pump rod was in, if I had to guess it looks like the third hole in, If my guess is right than you are getting a full shot of the accelerator pump when you step on it. Try moving it to the middle hole for starters. But only after you set your timing to 18*.

I hooked it up in the center one and that helped a little.

Originally Posted by STINEY

What is your total timing?

That's the number I'd be more concerned about. Get total in the 36-38 range and let the initial fall where it will.

I bet the total is way high. You'll have to verify that the timing marks are correct first. They are known to be off on occasion. Pop the valve cover, and turn it until #1 intake opens and closes. Then continue to turn it until the #1 piston is ALL the way at the top. (through spark plug hole to verify this)

Now look at the timing marks. Is TDC really TDC? If so you're good to go, set total timing to 36-38 at 3500-4000 rpm.

If not, fix those marks!

Good luck!

That is exactly what we are doing today, I will report our findings when we are done tuning.

Thanks to all of you for all of the support and tech suggestions. Ya'll are awesome.

[70rs/ss]

Check the mechanical advance like I said above if it doesn't move nice and smooth it could be the cause of the stumble as the timing doesn't advance untill the motor revs up into the rpm range, pull the dist while you are doing the checking. TX is a hot and HUMID state so yeah rust can and does happen!

[mclairmo]

After some time sitting with fuel in it, the carb may be gummed up. The tiny idle passages and orifices clog easily and can cause a rough idle and low rpm problems. I would say clean the carb out and/or rebuild it, paying particular attention to any small orifices. The fact that you have an HEI and that it runs well past 1500 rpms leads me to believe that the distributor is ok, assuming your timing is correct. You should verify initial timing, total timing and the amount of vacuum advance and dial it all in correctly. Also check where the vacuum advance is hooked up. If ported, then you will have no vacuum advance at idle, which is fine. If hooked up to full manifold vacuum, you will have some vacuum advance at idle, which may cause your engine to have too much advance at idle.

[70C10Toejam]

Originally Posted by 67ChevyRedneck

330hp feels a lot different in a 3,000lb-ish car vs. a 4,000lb brick of a truck

These trucks are WAY more aerodynamic than a brick. Well...until you throw the brick into a tumbler that is.