I have heard that this is a common problem with Barry Grant carbs. My friend had a 825 race demon on a 408 windsor that he bought used and had problems with it. Ended up going with a pro systems. I think only the earlier ones had problems so maybe you could send it back to BG to get it fixed.

 

I had heard that also but was hoping that we could get it fixed without sending it in.

It is getting so loaded up that when it launches it looks like a diesel then about 1000 feet it pops and sputters and won't hardly run.

you gets yours in the tens yet? looks like you were getting real close

 

That sounds pretty weird all right. In not sure what could cause that.

I ran 11.004, lol. I ran 3 different nights and went 11.05, 11.00, and 11.04. It is running out of gear so im gonna but some taller tires on it and try again. I still have a flex fan, too so if I dump that for an electric fan I should pick up a little.

 

Dub deos you time slips tell you what your 1/8 mile times are? Looks like you should be in the 7.0-7.50 range.

 

pretty consistent 7.65-7.67 over 8 runs so far this year

 

When you get the carb problem worked out, that things gonna fly

 

I am really starting to think that the carb has a bigger problem than me not being able to tune it right. So, plan B is to get it running good enough on the dyno July 15th and then next year sell the carb and buy something like this...

Tunnel Ram Injectors

 

How much vacuum is the engine making at idle / stall speed, and what acc. pump do you have in?

Nice 60's and 1/8th...

This weekend sucked for me, got a semi final trophy last weekend, got a perfect light this friday then went out in 3rd round with an -.002 red, went out 2nd round in pro sunday with an -.006 (had 3 time trials with -.006 to -.007, so atleast im consistant), went to 5th round sun in street. Put about 25 laps on the truck this weekend.

 

Ohh, and if you are thinking about ditching the carb, consider going to injected alcohol and switching to a rons toilet setup... they are very very consistant and there is a guy who tunes alcohol injection and works wonders with those setups who is local to the denver area..

 

I am not sure about the vacuum but I know it has 50cc acc. pumps. I am just scratching my head as to why a 13:1 motor with a nearly .700 lift cam and kaase p-51's will not pull the truck any better.

Sounds like you would be hard to beat with those reaction times. I was consistently slow on sunday and lost in the first round against a 9 sec corvette.

 

How are your power valves? Think the engine is making less vacuum than is needed to keep the power valves closed, and from opening too early?

Your 60's are pretty good. My friend pulls 1.5 60's in his 31 model a coupe, and runs mid 10's. But then again the 60's in my truck when running 14's were 1.90's.. so its hard to tell what ET a vehicle should run from the 60 footer.

Have you tried rolling your initial timing back a few degrees to see how the engine likes it? Checked the brakes for drag? Packed front wheel bearings with synthetic grease? Hows your timing system? are you running a vacuum advance? all mechanical advance? How does your converter feel? does it mush thru gears when you shift, or shift firm?

 

we removed the power valves and plugged them with brass plugs. This is straight from the horses mouth at Demon carbs.

Haven't messed with the timing at all due to the carb problems. Timing system will be messed with on the dyno at greeley machine on the 15th.

I think you are right on with the brake drag. One of the rear rotors from Willwood has never been quite right but a new hat is and rotor is a few hundred bucks.

I think that the motor pushes through the converter and it slips quite a bit. Even with the new gears it always wants to run at 6000 rpm. After launching i shift about 100 ft then the rpm drops to about 5000 then zips right back up to 6000 about the 1/8th then shift to third with the drop to about 5200 and right back to 6000 at the finish line.

Also having a disagreement about the spark plugs. The advice from 460ford.com is to run autolite racing plug 3934. MPG heads where we got the P51's from says to run a 29XX plug. Both are gasket seal chevy plugs but they have significantly different electrodes.

 

A few weeks back we bought some 1195 cfm sleeves for the demon and eventually found a 1195 off ebay. We tried the carb out and it hasn't ever seemed to work out that well. So last week i ordered some 1095 sleeves in anticipation of them being here of friday so I could re gasket the whole carb and change the sleeves in hopes to fix the problems. The sleeves never came as Jegs never informed me that they were in a two week backorder. However they made sure to charge me ahead of time for the shipping when they shipped the jet tool. I want to cancel the sleeves now and jegs refuses to refund the $7 for shipping. They said I could wait until the sleves arrived and then send them back but then I would have about $15 in nothing but shipping. So i think that I am done with Jegs.

Spent about 5 hours yesterday messing with the 1195. It still gets all loaded up at an idle and nearly dies from so much fuel. We took it back off and noticed the wood 1" spacer was saturated with fuel. It seems that raw fuel is leeking down past the venturi sleeves and dumping right into the intake. Decided to put the 895 back on it. Squared the jets at 90, removed the power valves and set the float levels and it runs 100 times better. throotle is good and actually idles without peddling it.

We cancelled the dyno for now since the 1095 sleeves arer still in transit and we can't cancel the order. Did I mention I am upset with Jegs. Going to run the truck next saturday and sunday and make a plan from there. At this point I just want to to run good at Pinks in August. Also still hoping to get a 150 nitrous plate and run 10.60-10.80 in Denver. Thinking that would be a better et class to get picked for the 16 car field.

 

I agee whole heartedly about Jegs haven't delt with them in a couple years because of that kinda stuff. By the way I got me a new toy. 76 F-100 shortbed. Never had a short truck befor but looks like it may be fun. I have a 460 sitting out here begging to be built right now it has a 302 and runs the 1/8 in a blistering 11.58 the guy befor me put 31-in tires on it with 3. something gears (tag is broke) so it is a dog till I hit half track cool thing is it has the C6 behind the 302 so all aint bad

 

I really like to look of the swb trucks and I want to get another one. Congrats on the new toy.