First race with the 512

[speeder440]

   we just got it togather started it and raced Saturday, 12.60 comp 512cid.,Eddyrpm,Baby roller cam,850 Holley,team-G,456gear,3600stall and 3300#Duster shifting 5600 for now. On the first with 84/83 jets it would run to 4500 and acted like it was running out of gas on the warmup,1st. T/T we put 85/86 but still doing it but ran 6.6047  ,    went to 90/91jets and slowed to a 7.1872 with no smoke,   so  we put 80/80 that was close to out the box jeting.  So we got in line with the bracket 1 cars( they knew we  was catching hell and let us make a pass) 6.5091 on the run-for-the-money we dailed 6.49 and ran 6.52. Had to leave it and race for the Wally in the first rould we got a .0070 on the lite to a .1040 that made it a win&next rould buy,killing 10mph,but  car was pulling the wheels about a foot and you could hear the motor stop running than when the car got close to the ground it would start going again.We won the 2nd. and got to run the buy in the 3rd. but  it did a 6.6158 on a 6.53 way,way off.It was getting worst you could see&hear it coming off the line pull the wheels ,no sould then go when it got back on the ground.So we dailed 6.61 and killed 5mph and lost in a dubble breakout.Now I don't have jet extenions or a rubber hose on the vents.We think its leaving the back jet dry or the gas coming out the front bowl and maybe flooding.Maybe the 850 is to small for the 512"er.Anyone ever had this problem,with the 451 same parts less compression it ever did it. The big motor dose help on the footbrake reaction times .007,.0031 and .023 in its first race---Speeder

[bOb shingler]

sounds like you have plenty of power. i would suggest a carb between 1000 - 1150 for that size motor. you also need to have enough fuel pump for it too. 

[Nitrous340dart]

my buddy is running a 496 BB Chuby in a beat down 68 step side long bed ranch truck we call the chicken truck .  Its about 11.5 with Canfield heads and custom solid roller cam.  He has a 1050 Dom on there with the 99 or 97  when we run it hard and then pull the plugs it shows its lean.  He hasn't boughten bigger jets yets so we'll see how tuning goes.  But I would think you 512 would need something like that.

[dodgee]

I have a 500 cube with a little less and have gone from 850 proform race carb to a 1050 dominator as per the carb chart on the holley website.

[dusterdarryl]

cubic inch x top rpm /3456 x 1.1 =  try that

[speeder440]

I have a 500 cube with a little less and have gone from 850 proform race carb to a 1050 dominator as per the carb chart on the holley website.

  Did you see a gain or did it run better  what is your shift point, was hoped that the jet extenions help some.I just got the film done and you can see the car getting on the wheelie about 15feet then falling very fast,all the way down unlike the old motor that when the wheels get back on the ground the front of the car stays up,so it completely stopping momentom .We had bad air that day every racer was off over more than .1 so I know theres more,it has 7 passes on the new motor so I know theres more. We was only shifting at 5600rpms all the has is a 3600 stall it shouldn't be running out of gas at 30 or 40 feet.I thought that running under 6000rpms I'd be OK with the 850 but the 512 is sucking the gas,it was useing alot more gas even with the 80/80 jets. 5 gallons of 110 in 7 - 1/8 mile passes@ $8per.

[67Dart383]

Nice Engine, What rpm is your peak Hp and peak Torque. also how many Rpm's did it drop after shifting?

[bOb shingler]

try raising the gas in the floats, it may be running dry also. fuel pressure should be 7lbs at the carb.

[speeder440]

try raising the gas in the floats, it may be running dry also. fuel pressure should be 7lbs at the carb.

  Ha Ha Bob,the float was alittle low  ,I remember that I lowed it because after we did the burnout and hit the brakes hard it would flood out of the vent tube and kill the motor,I will get a hose for the vent maybe that will stop it.I just put jet extenions and rise the fuel level with almost 8#pressure.This motor is way differrent than the 451.That cam has 308* and was more ruff in the 451 but smoother in the 512 it has about .600 lift after the lash.It really could use a bigger cam&carb with that compression it has.A gear change would help but its not spinning shifting at 5600 and crossing alittle over 6000 but if it don't starve for gas it mite run 6300 at the line,if that happens it needs a bigger carb,its going to be fun finding it out.We was in the 4th. rould and had .023 on the tree to a .080 bulb and lost on a brakeout because we couldn't dialin right .It mite have been having fuel problems going down the track too,just not so bad it killed the motor when we get it fixed we are going to win races with it,the high torque is great for reaction times. And Kidd,all the hell we was having with the jetting (because I was just making things worst the jets wasn't the problem)and trying to race for a Wally,I will try to look if I can but with 456gears all that stuff happens Quick ---Speeder

[ksdartguy]

Try the jet extensions get the floats back up and use a hose to let fuel run into the secondary bowl.
That should help the starting line.
The carb size will effect topend, not starting line much.

Rick

[JohnnyfromChicago]

Try the vent whistle to stop the fuel from overflowing.

[speeder440]

Try the vent whistle to stop the fuel from overflowing.

Can you tell me more about this vent whistle,what it looks like?

[JohnnyfromChicago]

Holley sells them through summit and jegs. They are these white plastic extensions that go in the front bowl vent. As the fuel sloshes back on accel the extension is like a long straw so the carb can breathe, but the fuel stays in the bowl. PN HLY 26-89 they are called vent tube baffles.

[speeder440]

Holley sells them through summit and jegs. They are these white plastic extensions that go in the front bowl vent. As the fuel sloshes back on accel the extension is like a long straw so the carb can breathe, but the fuel stays in the bowl. PN HLY 26-89 they are called vent tube baffles.

I have them but it still flooded it when the gas was at the site hole.The burnout box is close to the starting line so it is ruff to stop that fast,when I lowed the lever it wouldn't killed the motor.

[speeder440]

  I put the jet extensions & rised the fuel level,won the run-for-the-money with a 6.371 on a 6.37,then 3 -6.36s in a roll so I  think we got it. I was hoping for more but iam happyer that last week.Thanks for everyones input.They gave me another trophey from China boy I till'ya---Speeder

[sst3193]

What fuel pump are you runnin' Speeder?

[speeder440]

  That blue Holley(dead-heading) @ almost 8#s fuel pressure to the 850 Holley,I will get the black one next or maybe a Mallory.The motor is running really cool we can run it in the staging lane do the burnout and at the line 140* after a pass and get back to the pits 160* it has 14 passes now.I know the cam,carb is on the small side for a 512.But the number is like this Run for the money 6.3713,1st. rould 6.3620 on a 6.36,2nd.rould  6.3692 on a 6.36,then a 6.3679 on a 6.36    for the loss.It was cooling in the nite maybe 16*as the nite went on but it keep on running.We hung arould till after the race and made another pass and it ran 6.3580 so I think the jetting is real good 79 front/78 back 4781-5 850DP it was 75* and went to 59* a that the end. The 6.3580 is not the cars best with the 451RB it ran 6.341 in 48* air we was shifting at 6100rpms, now we shifting 5600 with the 512"er so for---Speeder

[67Dart383]

So whats yo 60' times? 

[mopar_eric]

On my demon I made my own with fuel line from one side to the other, and cut a small area out at the top to vent. Been good for years!

Congrats on the win!

[speeder440]

So whats yo 60' times? 

With the jet extensions 1.42-1.44s it has 29x10 and 456gears I think it mite be better with 4.10s with the 512"er.Without the extensions 1.50 to 1.56 60ft so that was one of the problems last week,we was jetting up and was getting worst without the extensions.Now we mite jet up and get some gain but right now it all about touque.Small cam,carb,convertor,512" and low RPMs=Touque