[how69ss]

Not sure if I should be frustrated or not. Need ideas and feedback. Nothing I do seems to make a difference. Are my expectations too high? (no, I am not talking about my life in general, lol.)

Here is the full combo and a summary of what I’ve done so far. Have about 50 runs in and I feel like I haven’t figured anything out.

All 1/8 mile.


Combo:
427 BBC, .30 over
hyd roller: 108 installed at 102.
242/254, 655/ 641
morel lifters
crane gold rockers
ATI damper
063 heads, 2.19/1.88 (flowed 300 cfm @ .600 on good ports, 290 on bad ports)
9.5 cr
Edl Air Gap (some port work and clean up done, gasket matched)
750 DP, jetted 70 primaries, 86 (drivers side) and 84 secondaries (on the dyno)
timing: 37 degrees
1 7/8 super comps
91 octane fuel
20/50 Brad Penn oil

engine dyno:

518 [email protected]
[email protected]

In the car, I would say it’s maybe 500 fwhp, corrected, as above.
Track DA usually 5000-7000.

mech water pump and clutch fan
M20 trans, CFDF clutch
4.11s, 9”,detroit locker,
3” exh, xpipe, dnyomax race mufflers, dumps
edl adj uppers, jegs adj lowers
moroso trick springs front and rear
air bags (just since this last time out)
90/10s up front, 3 ways, full stiff out back
Hoosier quick time pro, 28x11.5x10 on 15x8s.
1/2” fuel line, edl victor mech pump,
aeromotive reg, using just one outlet port to feed carb

With DA ranging from 4200-7000, the car runs between 7.97 and 8.08 with mph averaging in the 84.2-84.7 when I hit a 1.74 60’.
Shifts: have tried 5500, 5800, 6000. No measureable difference.
Launches: 4100 , 4500, 4900. 1.73 60’ best, usually 1.74. I dialed it back to 4100 due to traction problems.

Things I’ve tried:

35 degrees timing
+2-4 jet sizes
tire pressure: 14 psi
added mororso front springs
added rear air bags (10 psi)
various shift rpms
various burnouts (short burnout, 4 secs, works best)


Am I way off, or should I be running faster than this? Seems like even with the DA and all, I should be running at least 7.70s.

I have checked the obvious stuff. Carb opening up all the way, fuel psi (though not running down the track). The engine sounds great, temps 175-180 all day long. Initially the rockers backed off, but I reset them and they’ve been fine since. I have the original throttle cable still.

I have one weekend of races left. Kind of a relief. I am worn out trying to figure this thing out.

It’s a little frustrating to talk to a guy with a 67 camaro with a 327, slicks, T10 4 speed, near stock suspension, autozone clutch, who races once a year and is running the same times I am, and has run a best of 7.87.

It seems like nothing I change makes much of a difference. It’s like there’s a governor on my car.

My friend thinks it’s all traction. But it does pull the wheel off. I don’t get why it would run 7.97 with a 1.80 60’, then with a 1.74 on the next run, turn 8.05 and run about that on the other runs where I’ve had 1.74 60’ times.


Are my expectations not realistic?

 

[Mike]

Cam have a P/N - grind #?

 

[Tom Mobley]

have a video cam or know somebody who does?

it would be good to have a good side view and a good rear view video, like with a tripod.

seems like it would do better, but that altitude is a killer.

the governor deal often seems to be related to fuel delivery problems. any way to get a pressure gauge hooked up so you can see it in high gear? even temporary?

 

[how69ss]

Cam have a P/N - grind #?

Grind number CHB 292/310-08HR. PN 502000.

I got it from Straub who based it on my head flow numbers, etc.

We expected it to make around 560 hp @ 6500 and 480 tq @ 4300. But it ended up with more tq. 540 @4200, compared to 520 hp @5500, and still near 500 hp @ 6000. Didn't run it on the dyno past there. Recommended seat pressure, 165-210 and open 400-425. I don't remember where it ended up, but it was in that range.

My dyno guy said the motor had some of the best fuel numbers he's seen on a bbc and was really impressed with it.

 

[Tom Mobley]

back to the governor deal, valve springs can do that too. can you pull a spring, check the installed height and test the spring at that height?

 

[how69ss]

have a video cam or know somebody who does?

it would be good to have a good side view and a good rear view video, like with a tripod.

seems like it would do better, but that altitude is a killer.

the governor deal often seems to be related to fuel delivery problems. any way to get a pressure gauge hooked up so you can see it in high gear? even temporary?

Tom, I will try to get a camera on it this next time out. But according to other racers, it looks good leaving. Just doesn't mph. It feels like the rear is lifting if anything, now that I have the air bags. Don't have a lot of stored energy as the springs are new and the morosos.

I was actually thinking of jetting the carb up 6-8 jets just to see what it does. If there is (once again) no change, then for sure a fuel issue. Plugs look the same regardless of what I do with jetting. (MSD 6al box)

Originally I thought my problem was my holley reg and running just one outlet line from it to both bowls. So I switched that to the aeromotive and still just the one outlet line. I am thinking that I should run two separate lines, even though the aeromotive guy said one outlet flows plenty for my app.

I am also going to triple double check for kinks in my fuel line. I have that AQP hose from the tank to the pump and it's pretty tight going over the frame by the rear end.

 

[how69ss]

back to the governor deal, valve springs can do that too. can you pull a spring, check the installed height and test the spring at that height?

Tom,

I will for sure do that.

What do you think about the rockers backing off? I have poly locks, etc. Just heat cycling? I didn't reset them after the dyno runs and about 20 1/8 runs later, they started clattering and the car slowed down to 8.40s. So I reset them. 1/4 turn cold, which is what Chris told me to set them at. Went back to the usual times.

But could this be a sign of something else?

I'll try to get a fuel pressure gauge rigged up for this last time out. At least get that ruled out. The engine just sounds great going down the track though. Which makes me think it's more likely a valve spring issue, if there even is an issue.

 

[forcd ind]

are you pulling a plug right after a run, or driving it back then pulling a plug-sometimes i'll carry a spare plug, kill the motor right after a pass and swap one out, then i have a true reading of the plug
you should see the timing mark on the ground strap, and you have to look deep down in the plug for the fuel ring(i cut the threads off)
are the heads cast iron, seems 91 is kind of border line with 9.5, but maybe not
you def need an idea of running F/P, what size line from the pump to the reg-i would run 2 lines from the reg to the carb-you might be launching ok, but the carb is prob still full of fuel, then maybe runs low if not enough delivery
do you have jet exts. in the rear bowl, def a good idea with a stick car

 

[Mike]

Grind number CHB 292/310-08HR. PN 502000.

I got it from Straub who based it on my head flow numbers, etc.

We expected it to make around 560 hp @ 6500 and 480 tq @ 4300. But it ended up with more tq. 540 @4200, compared to 520 hp @5500, and still near 500 hp @ 6000. Didn't run it on the dyno past there. Recommended seat pressure, 165-210 and open 400-425. I don't remember where it ended up, but it was in that range.

My dyno guy said the motor had some of the best fuel numbers he's seen on a bbc and was really impressed with it.

OK ,that didn't help.
Wanted to see the full specs as you said the HP was @ 5500 and that sounded low for a 427.
Can you post the specs?
Cam ground with 4°'s advance ?

 

[SLOPAR]

Do you get any 330' et.'s on your ticket? You may not be that far off with the altitude. Keep in mind that having that stick in the car is going to make you work harder to get the same number as an automatic. What is your expectation?

 

[jeff swisher]

750 DP !!!
On a BBC...that is fine for grocery getting.
I do not like stock old style holleys, untill a few things are done.

Thin the throttle shafts,,install smaller screws in the shafts to hold the butterflys--throttle plates--..
polish the venturies
and i like to remove most of the air horn and blend into the throat,,

I had to do this to a few 3310's to gain the extra r's i was looking for and that is on little 350's
Of course you will need to re tune after
I tried many holley carbs out of the box with only jetting and float and mixture screw adjustments..and all fell way short of a worked over Holley

I run a lot of AFB's now..and did back when BBC engines ruled..

And 2 AFB's on the BBC was always the quickest way
I never had any 660's..or i would have tried them

These were 7000 rpm plus 396's and 427's
the cams were solids in the upper 240's on duration and the .580 lift range

Maybe them old cams just reved better

But you still need to adress that 750
I think that is one place where you are falling short

 

[Tom Mobley]

who can correct his times for the 6000 DA to sea level?

 

[Milan]

I believe you should hook up a vac guage to the intake and see what the reading is going through the stripe. I bet that 750 is WAY too small. I would bet that an 850 DP would really let that engine breath. I agree with Jeff; a 750 is fine for a grocery getter...

If you post your incremental times it would help us analize your runs.

Milan

 

[how69ss]

are you pulling a plug right after a run, or driving it back then pulling a plug-sometimes i'll carry a spare plug, kill the motor right after a pass and swap one out, then i have a true reading of the plug
you should see the timing mark on the ground strap, and you have to look deep down in the plug for the fuel ring(i cut the threads off)
are the heads cast iron, seems 91 is kind of border line with 9.5, but maybe not
you def need an idea of running F/P, what size line from the pump to the reg-i would run 2 lines from the reg to the carb-you might be launching ok, but the carb is prob still full of fuel, then maybe runs low if not enough delivery
do you have jet exts. in the rear bowl, def a good idea with a stick car

dang you guys are awesome! Just went to lunch and got back, and here's all this good stuff!!!

Yes, iron heads. I will switch to using two outlet ports, one to each bowl. I have jet ext. -8 line on the whole system right now.

OK ,that didn't help.
Wanted to see the full specs as you said the HP was @ 5500 and that sounded low for a 427.
Can you post the specs?
Cam ground with 4°'s advance ?

108 lsa, 102 degree intake lobe. @.050, intake op 19, cl 43; exh op 61, cl13.

Do you get any 330' et.'s on your ticket? You may not be that far off with the altitude. Keep in mind that having that stick in the car is going to make you work harder to get the same number as an automatic. What is your expectation?

Just 594 ft. So on my best run, it was:
1.8
7.448 (@594)
7.972
85.89
DA 5877

750 DP !!!
On a BBC...that is fine for grocery getting.
I do not like stock old style holleys, untill a few things are done.

Thin the throttle shafts,,install smaller screws in the shafts to hold the butterflys--throttle plates--..
polish the venturies
and i like to remove most of the air horn and blend into the throat,,

But you still need to adress that 750
I think that is one place where you are falling short

who can correct his times for the 6000 DA to sea level?

Not a stock carb. It's a race carb, downleg boosters, no air horn, etc.

I talked to two custom carb builders and both spec'd a "950hp" for my motor. The one suggested a 980 cfm, and the other person (patrick at pro systems) an 830 "real cfm" that was a street/strip carb. The first one was an all out racing carb.





If you post your incremental times it would help us analize your runs.

Milan[/QUOTE]

There's just the 594 ft time.

I have worked it all out on the calculators in terms of DA and all of that, and I'm still .5 off in terms of quarter mile time. Maybe .3 for the 1/8. My best run adjusted for DA would be about 12.0. I know from what everyone posts that 500 hp cars run mid or even low 11s.

I do think (know) that the manual trans is making this all far harder. People who have manual trans cars that really work all have adj clutches and slicks. I need to try a full slick.

In terms of the carb, the fact is that it did make 520hp/540 tq on the dyno. Now the dyno isn't racing, but I think that would indicate that it works at least moderately well.

Maybe it's not that far off? I don't know. That mph just seems low.

Great ideas everyone. I am making a long list!

 

[Mike]

who can correct his times for the 6000 DA to sea level?

http://www.dragtimes.com/da-density-altitude-calculator.php
http://wahiduddin.net/calc/calc_hp_abs.htm

 

[Tom Mobley]

tire spin is why I mentioned a quality side view video. paint some marker stripes omn the sidewalls, see how much spin you're getting. that could the majority of the problem with the short times.

 

[how69ss]

http://www.dragtimes.com/da-density-altitude-calculator.php
http://wahiduddin.net/calc/calc_hp_abs.htm

a 7.95 would be a about a 12.40. Corrected that's:

Stock and Mildly Modified Naturally Aspirated Engines
11.47 @ 0 MPH

Extensively Modified Naturally Aspirated Engines
11.678 @ 0 MPH

I have checked that before. So maybe I am not so far off. It just seems like other people are running less power and turning better times. I know I have to make sure the fuel delivery is working like it should.

I also really think this manual trans is part of it too. It is darn hard to hook with a 4 speed and decent torque on a moderately prepped track. But then, like I said, that camaro was running just as fast as me. Maybe him having less tq actually helped him.

My issue is if I go with the mt manual trans slick, then I have to be VERY careful. This CFDF clutch I have is like an on/off switch.

In all reality, if I really want it to work, I have to go with a slipper clutch. But I don't think I am up to the task. It also pushes the car into almost a race only deal. I don't have tons of time to work on this car, and I always wanted it to be a street/strip car that I could even drive to the track. I don't think this is really possible with a manual trans.

Obviously, people do it, but they are giving up quite a bit at the track, and I doubt they bracket race 20 times a year.

 

[how69ss]

tire spin is why I mentioned a quality side view video. paint some marker stripes omn the sidewalls, see how much spin you're getting. that could the majority of the problem with the short times.

Got the stripes on the side. I am pulling the drivers side tire off. I do need to take a closer look though.

 

[Tom Mobley]

know anybody where you could borrow a quality carb like a Pro-Systems HP 950 or similar.

per the carb calculators a 750 should be good to close to 7Km on a 427. This is not a 496/540 deal here. The altitude might make a difference though.

these carbs are not cheap, be nice to try one before the old wallet-lightening deal. If I had one I'd send it to you for a weekend but I don't. Anybody else willing to step up to help a brother out?

 

[how69ss]

know anybody where you could borrow a quality carb like a Pro-Systems HP 950 or similar.

per the carb calculators a 750 should be good to close to 7Km on a 427. This is not a 496/540 deal here. The altitude might make a difference though.

these carbs are not cheap, be nice to try one before the old wallet-lightening deal. If I had one I'd send it to you for a weekend but I don't. Anybody else willing to step up to help a brother out?

Tom,

I hear you on the carb. The custom carbs run $700-750.

So, the carb might be hurting me on the top end. I know I do need to sort out the traction.

My plan, after looking at the ideas here, is to replumb my reg to carb, and get an ext fuel psi gauge hooked up. There is only one weekend of racing left, and really, I need to look at it as a purely diagnostic outing. Just to make sure I am getting fuel and to really document my launch what the car is doing.

As far as the revs, that's those hyd roller lifters to some extent. It's just not going to hit the rpms like a ft. I have been studying the whole beehive spring deal, though.

So, I will:
1. replumb reg to carb
2. add ext fuel psi gauge
3. get some vid the next time out.

I really need to find a bigger carb to try, just to see what it does to my mph (why don't they have carb rental shops? That would be a great gig at a track, wouldn't it?)

My friend has an 850 pro form main body carb on his monte. I'm sure he'd let me borrow it for an afternoon. I'd at least get some idea if there's a difference.

The frustrating thing has just been the way the car runs the same regardless of DA, jetting, timing, rpm shifts, suspension changes.

For next season, which starts in May:

-Check valve springs
-anti roll bar
-MT manual trans slicks (or TH350)
-Bigger carb, if I find that trial runs shows significant (a couple tenths) improvement.