holley ultra hp 750 installation on 351

[vector1]

purchased new in the matte black finish. had to then purchase the inlet because it has 9 3/4" c-c inlets which cost $100 from holley, not the same as barry grant or previous holleys, earls has them at a little more cost. installed on a fms crate engine 351 with afr185 heads which upped the compression to 9.5 using the z303 cam or the wildest they use i believe and rpm air gap intake.

finish was real nice and i couldn't see any flaws, everything is adjustable for those who can't leave well enough alone. i installed it without making any adjustments to see what their tune was. i had to drop the idle from about 1500 with the idle ez. the floats were set a little high initially with the sight glasses higher than normal the fuel level was still 2/3 of the way up the window, instructions say 1/2. there are sight glasses both sides so you can look completely through the bowls.

i did install the supplied main jet extensions in the rear bowl. i had to use an impact on one of the jets as it couldn't be removed by hand and the jet was chipping out even though i was using a hollow ground screw driver. doesn't take much to hold a jet in but can take a bit to get it out.

i dropped the float levels one complete turn and drove it in that condition without checking the level and other than that as above it drove real nice, no hesitation, stumble or similar problems. power was good, fires right up and idles nicely with clean crisp acceleration. hard braking and cornering didn't seem to effect it much. one complete turn of the float adjustment dropped the level to the bottom of the sight glass so i moved them back up 1/2 turn and will have to drive again to see if there is any effect.

real happy with this carbs performance so far and do not forsee any tuning, finish was also good. the finish on the carb just about matches the paint scheme on the car.

[ERA Chas]

Vector-no inner wells on a JBL?? Doesn't flying stones make a racket and blast the engine bay?

[vector1]

Originally Posted by ERA Chas

Vector-no inner wells on a JBL?? Doesn't flying stones make a racket and blast the engine bay?

not really, have to clean out the small rocks every once in a while but not too bad. there were fender wells but they are a pita to work around and make the engine bay hotter. also prefer to look at all that fine engineering rather than sheet metal, would pull the carpet if that wouldn't make such a mess....

[ERA Chas]

^^Understood-makes sense.

[vector1]

thought i'd give an update on this fine carburetor. couple tanks of gas under various conditions and all is well. car starts right up when cold and after a bit of warm up runs good, idles real good when hot. accelerates with no hesitation anywhere. can cruise in 5th all the way down to about 1800 without any undue revolt and accelerate from there. plenty of power and all i could ask of a carb. there is some missing under hard braking and turns but that is to be expected, nothing i wouldn't expect. at some future day maybe change the floats out for some road race units is about the only change i can see. otherwise haven't touched any of the adjustments other than the initial idle eze and float adjustment. i think in golf parlance that would be deemed all square!

[vector1]

so i installed the road race floats i purchased from braswell today. buy the float, and they include 2 screws, the pin, and spring. they discombobulated my order so they sent me a set of free gaskets with the second one. very nice of them.

did notice the carb has 5 emulsion bleeds, with 4 of them drilled. i have seen 2, and 3, but never 4. also the dry break (?) at the top of the emulsion well was not what i expected to see.

another thing i did notice, i was letting the engine warm up so i could adjust the idle a/f ratio and had it adjusted so i was going to put it in the car hole and dropped the hood with out the air cleaner installed. the engine made a dive for low idle and sounded like it was going to die. i thought maybe something had dropped into the carb so i picked the hood up and the engine picked back up!

so i surmised that with the hood down and nothing to direct the air that the blowing fan was disturbing the air over the top of the carb, or the hot air was effecting it, but it was cool out and i don't think the hot air would have that much of an effect. which led me to wonder how many guys with individual runner setups not running air cleaners run into tuning problems.....

anyway, put the air cleaner back on and no effect, then dropped the hood and no effect again. very interesting.

[FWB]

that is interesting.....how close to the airhorn does the hood get? i can't imagine the hood affecting flow any differently then the aircleaner.....weird

[vector1]

the air filter is 2 x 12, but i imagine the problem arises when the air streams along the underside of the hood and meets up with the top of the carb. looks dusty but is not.

[vector1]

Holley 4150 HP Carburetor - Inside Holley's Brand-New Oval Track Carb - Circle Track Magazine

[SPF1061]

Vector -
Let me ask a question about the road race floats you bought. Are they metal and soldered or are they plastic and epoxied? I run an AED carb, which I love, but their road race floats are plastic and the #%*! ethanol fuel eats the glue. I am forced to run street floats which create major bogging / stalling under hard braking and hard turns. If you have found metal road race floats please let me know the source. Thanks.

[vector1]

Originally Posted by SPF1061

Vector -
Let me ask a question about the road race floats you bought. Are they metal and soldered or are they plastic and epoxied? I run an AED carb, which I love, but their road race floats are plastic and the #%*! ethanol fuel eats the glue. I am forced to run street floats which create major bogging / stalling under hard braking and hard turns. If you have found metal road race floats please let me know the source. Thanks.

i bought mine from braswell, and they are supposed to be good with alcohol if i remember right. 163051 & 163010


Braswell Carburetion-Severe-Duty -- Floats - Page 1

[SPF1061]

Originally Posted by vector1

i bought mine from braswell, and they are supposed to be good with alcohol if i remember right. 163051 & 163010


Braswell Carburetion-Severe-Duty -- Floats - Page 1

Thanks. How long have you ben running these? The problem I had was not with the float material per se, but the epoxy that was used to attach the arm to the float body. The ethanol in pump gas was slowly dissolving the epoxy.

[vector1]

i do not use fuel with ethanol, but i went out and looked at another exact set and the arms are molded in, no epoxy. when you order ask them and report back, i would be interested in knowing their response.

[lovehamr]

On the air flow disturbing the idle; a side note is that when I was dynoing my engine we ran it all day with no air cleaner getting as much out of it as we could. Just as the dyno operator was getting ready to shut everything down for the day I suggested we try the air cleaner which is a Holman Moody drop base and top with a K&N 14x3 filter. The 462" FE immediately picked up 5hp. We pulled it two more times with the same result. Mine defiantly makes more power with the air cleaner in place and I can only attribute it to air flow management into the carb.

[SPF1061]

Originally Posted by vector1

i do not use fuel with ethanol, but i went out and looked at another exact set and the arms are molded in, no epoxy. when you order ask them and report back, i would be interested in knowing their response.

Great info. Thanks.