I went yesterday to the track and got my new best ,only problem was the belts throwing ,I can not rev high before the green light :
first pass :
60 ft. 1.81
1/4 e/t 12.8
1/8 e/t 8.1
103.4mph

second pass more rpm shifting the th350 at 7000 rpm to second and 6500 rpm to third :
1/4 e/t 12.62
1/8 e/t 8.02
speed 106.1 mph
60ft. 1.79
330 ft. 5.1
1000ft. 10.50
third and last pass because belt throwing problems ,I went to the track with 4 bels and the last belt was in to get back home ,NEXT upgrade serpentine belt for sure .

1/4 e/t 12.62
speed 106mph
1/8 8.04
60 ft. 1.83
330ft. 5.20
1000ft. 10.51

I only install the headers and a -8an from tank to carb inlets and a 1/2" gas tank pick up line and went from 13.1 e/t to 12.62 e/t :eek:
THANKS for all who help me with this excellent fuel line advise upgrade graemlins/thumbsup.gif

Congrats on the new bests,,,I imagine the headers is where your e.t. came from though. Align the pulleys and you'll quit throwing belts, I don't have deep groove pulleys and I've never thrown a belt.

Nice job..congrats on your new best and new found performance graemlins/thumbsup.gif

Thanks Robert and Chris ,I will verify the pulleys again before the serpentine pulleys investment .

I had a horrible delima for about a year on throwing belts on my SBC. It did not matter what I tried I would lose a belt in a day of racing.

Recently I installed the pullies from a 86 motor with a flat rib belt but still uses old style brackets. This cured my problem and was only 60.00 from the bone yard instead of 300.00 for a serpinteen set up.

I beleive BBC trucks from 85-88 will have the setup you need as long as you are using long water pump.

do you run a thermostate in your car? im sure you do........throwing belts in a bbc can come from the water pump hydrolocking.....your engine spins up so fast that the water builds up inside the water jackets and has no where to go and in turn almost brings the water pump to a stop and the belt gets thrown off...this shows up when the engine is still cool and the thermostate isnt open....like between rounds of racing when we cool the engine.....take the thermostate and knock the center out of it and put the rest back in to slow down the coolent some........think im crazy.....i have blown water pumps off the block because of this and the first signs of this was throwing belts......having everything perfectly aligned not a single pulley out of place......even running an underdrive pulley on the alt.

being so frustrated i would tighten the belts even harder....then i was starting to blow water pump gaskets out..........then i put a belt on so tight......i blew the water pump off in my 60 ft.......after i replaced everything and didnt tighten the belt so tight i was still throwing them.......so then i tried some sticky glue spray on the belt....just to see if it would do anything.......could not figure out why i was throwing them.......well now that the belt was sticky with glue spray.....and not so tight.....this was enough for the belt to stick inthe groove and it blew my water pump back off again.........


the cure for all this headache....i took the thermostate out........never threw a belt again.......

in my first 6 years with bbc i never threw a belt........when i started to make enough hp to run deep into the 12's then thats when my problems started........with a stall and 7200 rpm shifts......then engine wanted to rpm faster then the water pump could handle........so something had to give........and it was the belt.......so right now your belt is your safety line from pushing water pump gaskets out or blowing of the water pump.........still think im crazy..........

ever wonder why you bbc dont throw a belt near as often when your on the street with it fully warmed up........because the thermostate is open and it has somewhere to go.....

and yes this was even with that short bypass hose hooked up.......

just thought i would share.........

thats great for your times.......but dont be surprised when you start making full passes with your belt on for the full run that you will loose a few mph in your trap speed........it was not uncommen for my bbc at this hp level to gain 2-3 mph when my belts flew off.......bbc water pumps eat up a lot of hp.......

ddeennis

that's pretty interesting! I used to have a lot of trouble keeping the belt on my BBC. I always thought it was from twisting it to over 7000. Stock pulleys and stock long style water pump and a quality fan belt. Checked it over and over for alignment and it always checked out fine. Just couldn't keep that sucker one! You may have just given me the explanation. Thanks!

Dave

How are you checking the pulleys for alignment?

The best method I have found is to place a small pen led pointer on the pulley and rotate it till the beam ligns up with the other pulley.
Add shimms till the beam is at dead center of the other pulley.

I have had the same problem even after aligning the pulleys.
A friend requested that I try Dayco's Top Cog belts and I thought he was crazy.How could a belt make a difference :confused:
To make a short story, I tryed the belts and I have never had a problem again :D

A friend of mine also just went through this.
He changed to Dayco Top Cog belts and problem solved ;)

Don't go and order a plain old Dayco belt.It has to be the Top Cog line.

Richard I will try to find a bbc 85-88 truck ,thanks .
DDennis thanks for the good inf. but I am not running a thermotate. I took the pump out today and found that the lower radiator hose inner wire is in pieces in the pump inlet and the hose is a little close in the turn it makes from radiator to pump ,this bend is maybe causing the same problem you had, Hydrolocking . I had the tossing belts problem "solved" went running 13.1 E/T with a DAYCO belt and some pulley alinig ,but now is back more , last Saturday I toss Three belts and two were Dayco cog log belts $14.50 at PEPBOYS each :mad: .
I will change the hose and get sure the water is runnig free and causing this blocking problem

Thraser I will try to get a small pen led pointer graemlins/thumbsup.gif

that was some of the same problems i was having the inner wire was getting sucked up into the pump and the hose was being sucked shut.....i noticed the hose being sucked shut when i would rev the motor in park......i used heavy duty hose with the wire molded in ......but i fixed thatand i was still throwing belts.....then it was after i removed the thermostate it stoped.......so that might be whats still causing the belts to throw......the other idea i had if the thermostate didnt work i was going to modifiy the stock pump by removing some of the impellers to slow down the water flow...........i never got to this point.....but i still kinda think that even once everthing was solved like pulleys aligned and bottom hose strong enough not to be sucked closed and removal of thermostate to give the pump every chance to move all the water it wants to in such a short period of time the engine revs.......that the pump just cant keep up with the demands of the rpms that happen so quick.......those bbc water pumps just move so much water.....as you saw with your spring being sucked up thru the hose......theres just alot of suction that happens so quick when the engine revs rapidly......

thats where i got the idea of removing the impellers..like every other one in the water pump if the problem would remain........dont know how it would effect cooling at slower rpms for daily driving......but my thinking was that it should move enough water to keep the engine cool.....and if it didnt then i was just out a 20 dollar water pump for trying......

like i said i never went that far.....even at 123 mph runs......

one thing i know that help to some extent was to break in the belt.....new belt get runs for about 20 min of regular driving then gets retighten.......new belts stretch.....and become loose....so this might help you as well once you get your bottom hose replaced.......dont bother to buy the lower hoses with loose springs in them buy the ones with wire molded in......

hope some of this helps.......

I use the hoses with the wire molded in, but I too run a thermostat and a stock water pump, hit 7k in the water box with the old motor a few times and still yet,never have thrown a belt.

Doesn't the normal heater hose circuit provide a flow path for the pump to bleed off pressure? I've never seen a pump want to lock up from hydrolock. Interesting.

I have no heater hoses either,,,just plugged em off at the intake and water pump. The heater core sprung a leak a couple years ago, I have a new one in the garage,just never replaced it yet.

The wire molded hose you guys mention is THE UNIVERSAL FLEX hose ?? this is my only option ? I really don't like the look of the universal flex hose ,but if there is no other option I will go with it .

just a thought, but you might want to check the hub on the water pump shaft to see if it has started to walk or slip. unfortunately they are pressed on, spinning them real fast with a big old mechanical fan doesnt help.

i mention this because the last time i was at the track with my chevelle it threw a belt and ended my day. after that it kept throwing them, so i disassembled everything and noticed the water pump hub had slipped. this was on a nearly new aftermarket pump, so i pressed the hub back on and tack welded the hub on the shaft and havent had any problems since.

i was using a 17" 7 blade mechanical fan at the time(no clutch). its pretty heavy, which may have had alot to do with it. when i repaired the pump i also swapped back to a flex fan i had laying around, eventually im going to put either a clutch fan or electric fans on it.