Holley 1850, 600cfm

[JMcTurnan]

I got a 351w, should this carb give much power? Because it doesn't seem to like I wish it would. Use to have the stock marine holley on there, and it beasted that truck. What do you think? Are the jet sizes good?

[coletrain777]

I had that exact carb on a 327 chevy that made 422 hp and 399 ft/lbs on the dyno and it worked great. It wasn't anything special, just an old holley. It should work just fine for your 351w.

[JMcTurnan]

Wierd cause its really not. I have a couple of ideas, the float settings will that affect that? Does the passing gear rod make that much difference? Timing, my vaccum gauge says im running good, but the timing light and harmonic balancer doesnt match up to mark.

[coletrain777]

The float settings affect everything. If your float settings aren't right you don't need to try anything else as you will just be running in circles.

As for the kickdown rod, it will make a difference in acceleration. It would be like driving a manual transmission and trying to floor it in 5th gear, and then flooring the car in 2nd gear, lots more acceleration in 2nd gear. If the kickdown rod is not attached the transmission won't go from drive to 2nd when you need it to downshift.

When you say that you timing light and harmonic balancer don't match up what are you saying??? Are you stating that you think the harmonic balancer is separating and the timing marks are off? Sorry I can't be more help but I don't understand what you are referring to.

[JMcTurnan]

Well I don't know why its off to be honest. But when we put the new timing chain on we had #1 plug up, and we lined up the dots. But the harmonic balancer doesn't show its in time, but the vacuum gauge does. What would cause this?

[fitzwell]

Well I don't know why its off to be honest. But when we put the new timing chain on we had #1 plug up, and we lined up the dots. But the harmonic balancer doesn't show its in time, but the vacuum gauge does. What would cause this?

Balancer ring slipped?? How many inches of vacuum do you have at idle, and what do the timing marks on the balancer show??

[JMcTurnan]

They don't know any marks if Im right. I believe it runs steady at 48 psi about.

[fitzwell]

They don't know any marks if Im right. I believe it runs steady at 48 psi about.

look at the balancer & check for some sort of markings. you might need a wire brush the thing, but they should be there. If you can't catch 'em with a timing light as the motors running,(don't forget to disconnect & plug the vac line to the dist) look closely at the rubber on the balancer, between the hub & outer ring, if it's cracked, parts sticking out..ect, you're gonna need a new one. Depending on the condition of the motor, you should have between 16-18 in of vacuum at idle.

[JMcTurnan]

Which is about what it runs, 45 psi is about equivelant to that. But I cant exactly time it, I could maybe be one tooth off, and maybe that spacer is busted. Ill check that out, I didn't realize it wasn't truely one piece.

[70_F100]

45 PSI is NOT equivalent to 16-18 inches of vacuum.

PSI is PRESSURE.

Vacuum is SUCTION.

As a former technician turned engineer, I somehow don't see ANY equivalency in that...

[JMcTurnan]

Well I misread my gauge, it has numbers on top and bottom, so I wasn't surw which one was witch. But my vaccum gauge has a good zone from about i think 15-20 inches of vaccum. It read pretty steady right in the middle at around 17-18.

[JMcTurnan]

I think I found out why about the carburetor
Tell me if this sounds right...
The old carb has vacuum secondaries, the seller of the carburetor told me they gradually open.
My older carbs had mechanical secondaries, so they opened quick which the push of the pedal instead of gradually, he said that would be a cause of differences of booking it from stopped posistion.

[fitzwell]

I think I found out why about the carburetor
Tell me if this sounds right...
The old carb has vacuum secondaries, the seller of the carburetor told me they gradually open.
My older carbs had mechanical secondaries, so they opened quick which the push of the pedal instead of gradually, he said that would be a cause of differences of booking it from stopped posistion.

sounds about right. Vac secondaries work for about 95 % of the applications out there. On your 01850, you can tailor the speed at which they come in by changing the spring in the secondary diapraghm. After you get the timing issues dialed in. Set the points, set the timing, (adjust to the highest vacuum reading you can get), then adjust the idle mixture screws on the sides of the carb. You will do this more than once. Then take the truck out & drive it. If you get any "pinging" back off (retard) the timing just a bit...and repeat.

[JMcTurnan]

Alright thanks!, Ill look at all that.

[fordman]

let us know what you end up finding out for sure.