Good Morning Folks - When my mechanic helped me get my big block started, he could not get it running well with the Quadrajet.

He put on a Holley - I know nothing about Holleys.

Can someone look at this link and tell me which model this one is, or how I can tell.

http://www.americasgate.com/holley.html

The car came back running reasonably well but it has degraded terribly in the past 500 miles. I know there are some timing problems but figured I need to find out which carb I have before I can start trouble shooting.

Thanks...Tim

 

That's a 3310 I believe. Vacuum secondary. Probably a 750 cfm.

 

Little more info would be helpful!
Year, cubic inches, how long it's been sitting -
Holley's are stamped on the front drivers side air horn, but I think it's a 3310-1
3310 has rear jet plates
750 vacuum secondary - dual inlet - no rear jet plate
Very used - needs a filter!!
Probably needs a timing chain and gears -

 

Here's a thought. Find a "mechanic" who knows how to tune a Qjet.

 

X2 Joe. If he can't tune a Qjet, I don't think I would even call him a mechanic. It ain't that tough.

 

I'd tell you to send it to me to fix, but when #5 Brother sent me his, UPS bent the floats on the way back, they tossed/dropped it so hard!
He's in Jersey.

 

Hey Guys - Thanks... ok here are the details.

Brand new rebuilt 455 to 1970 W30 specs. Did not recieve cam card with engine but builder said 308 duration/272 lift.

Couldn't get enough vacuum with the Qjet. Mechanic thought perhaps the cam was a tooth off. Using MSD 8529 Pro Billet Distributor. The carb was rebuilt when it was installed two months ago.

On that one picture, you see there is some type of cable hookup that is empty, what would that be for?

Car is behaving like there is a vacuum leak, but I can not find one.

I kind of need a starting point, because I am clueless.

 

Well, a 1970 W-30 didn't use a 308 deg cam, an MSD distributor, an Edelbrock intake, or a Holley carb, so I'm not sure what part of the motor IS "built to 1970 W-30 specs".

The "cable hookup" is for a manual choke cable. It's missing because the choke has been removed from this carb. Your "mechanic" put this carb on? Again, find a mechanic who actually has a clue. I'm even less impressed by this one. Apparently all he has is a hammer and everything looks like a nail.

 

Plug all the vacuum outlets on the Q-jet + manifold, after making sure the base gasket is correct.
Get it to run the best you can - should get at least 12 inches of vacuum.
Once smooth, plug in everything one at a time, see if it changes, and adjust accordingly.

 

Hey Joe,

To clarify - the block and heads were supposedly done to W30 specs. I see the cam does not look correct, looks more like a 350.

Yes, there are aftermarket parts, the car originally had a 350 and when I blew it up decided to go with the 455. I did decide to use some after market parts, I'm not selling the car as a "factory correct" machine.

Anyway, lets not beat up the old mechanic or the engine builder. It is irrelevant. The block is built and the mechanic did get the car running. I haven't found any mechanic yet, that has done anything exactly the way the customer says.

Help me figure out how to go from here. How can I go and get this mess running correctly.

Thanks...TP

 

Not trying to beat up on you, your engine builder, or your mechanic. Just trying to get complete and accurate info as well as combat "truth decay". Just be aware that a 1970 W-30 short block is no different than any other 1970 455 with high compression pistons and unless you have F head castings, your heads aren't built to "W-30 specs" either.

Back to your original problem. From the little we can determine from the photos, the Holley has been screwed with. Choke has obviously been removed. Without knowing what else has been done to it, it's difficult to tell what it needs. The Chinesium die cast adapter plate under the carb can be warped, causing a vacuum leak. The carb could have any one of many vacuum taps leaking. The carb could be jetted or otherwise adjusted incorrectly. The problem could also be completely unrelated to the carb. Personally, I'd get a properly rebuilt Q-jet, ditch the cheap, restrictive adapter, and get it adjusted properly by someone who knows what they're doing. It's unfortunately impossible to provide complete info on diagnosing a problem like this without having the car in front of you and knowing exactly what's been done to it. It's not stock, so we have no baseline to work from.

 

Yea - I agree. - I have the original Qjet from the 71 350. Think that would work? It was running perfect on the 350. Or would it at least be good enough to get a baseline?

 

If it was running correctly on the 350 and it hasn't been sitting so long that the gaskets have dried up, then yes, it should work on the 455. It won't be perfect - you will need to adjust air valve wrap and idle mixture and should change metering rods and possibly jets to optimize it - but it should run.