[mkpatrick]

I noticed that the place local here that does chassis dynos for people, will measure headflow.

Will this measurement tell me anything useful in regards to whether or not I'm under or over carbureted or maybe my heads are insufficient in some way?

If not, what is this measurement good for and how can it serve me?

[68rs406]

Basically you build your motor around your cylinder heads, or get heads to fit your needs, so the information is nice but will only be one part of the equation. Good info to have though when setting out to build a motor, I say find out! So what shop are you talking about in Tacoma?

[mean buzzen half dozen]

Originally Posted by mkpatrick

I noticed that the place local here that does chassis dynos for people, will measure headflow.

Will this measurement tell me anything useful in regards to whether or not I'm under or over carbureted or maybe my heads are insufficient in some way?

If not, what is this measurement good for and how can it serve me?

Tell us your build & I am sure we can give you some ideas what your heads flows & what size carb you need.
MBHD

[mkpatrick]

Originally Posted by 68rs406

Basically you build your motor around your cylinder heads, or get heads to fit your needs, so the information is nice but will only be one part of the equation. Good info to have though when setting out to build a motor, I say find out! So what shop are you talking about in Tacoma?

Turbo technology. They are down near S. Tacoma way...
I dynoed there about a year and a half ago but didn't do headflow because that part of the machine was inop that day.
I want to go dyno again because, I want to see what this transmission has done for my power to the wheels if any.
(actually, I went from 12.24 to 11.60 but much of that was curing a hook problem, but the tranny guy said that my 3rd gear was toast so I wonder if that will change the numbers since I did the pull in 3rd gear)

I figured headflow would tell me if I am under or over carbureted.

[mkpatrick]

Originally Posted by mean buzzen half dozen

Tell us your build & I am sure we can give you some ideas what your heads flows & what size carb you need.
MBHD

I didn't build it. I've been trying to figure out what I have. Its a BBC, I am told its 468.
Its an all roller motor with a Holley 850, oval port iron heads (not sure whats been done to them as far as porting but they've been glyptolled, which tells me some work may have been done to them)
Its higher compression because it pings something fierce if I run anything less than 100LL in it. (even if I retard timing)

Edelbrock Victor 454-O manifold, hooker competition headers, T400, 4.88 gear, 1350 joint.

Some other things besides the tranny that is different is a MSD distributor and coil, a different stall converter, its a Hughes 3500 stall but it still flashes to 4600. The one before that flashed to 5200.

And the only other thing is that my crank case is not ventilated to the headers via a bung like they used to be. Its now just ventilated with breather caps.
I tried a PCV valve and that was a disaster. Very bad detonation.

So hopefully headflow will tell me if I need better heads or bigger carb.

What sort of difference do you estimate?
The last time I dynoed, with a accel dual point, headers with bungs, a burned 3rd gear and a 5200 rpm flash, it showed 335 hp and 328 ft lbls of torqe.

[zdld17]

You said a word that caught my attention, "pings" , you said its hi compression but did not say specifics. What is ratio and what is quench?

[68rs406]

Ahh yes, turbo technology, while I have never directly dealt with them I have some friends that have, they definitely have a great reputation.
So they can flow your heads on the motor? Interesting, I have never seen that before but could see how it could be done.
Knowing flow could help you with carb sizing, but even more on cam choices, but it doesn't sound like you really are concerned about a cam. If you knew head flow and cam specs it could definitely help with tuning and carb sizing, I figure it's info worth having regardless, unless it's really expensive to do.
I also agree with Don, the pinging could be an issue, because if it's on the verge and you hear it occasionally, chances are you are not hearing it a lot of the time, pinging can be very destructive to a motor and a serious power robber. Whats your cranking compression? What info do you have on the motor build thats for sure?
I think based on the info you have about the motor and times you have run, you very well could be leaving a little (or a lot) on the table, performance wise. A stout 468 could easily put you well into the low 11's, I think it's time to dig into the motor and find out what it is before any changes are made, anything you can find out is a plus.

[mkpatrick]

Originally Posted by 68rs406

Ahh yes, turbo technology, while I have never directly dealt with them I have some friends that have, they definitely have a great reputation.
So they can flow your heads on the motor? Interesting, I have never seen that before but could see how it could be done.
Knowing flow could help you with carb sizing, but even more on cam choices, but it doesn't sound like you really are concerned about a cam. If you knew head flow and cam specs it could definitely help with tuning and carb sizing, I figure it's info worth having regardless, unless it's really expensive to do.
I also agree with Don, the pinging could be an issue, because if it's on the verge and you hear it occasionally, chances are you are not hearing it a lot of the time, pinging can be very destructive to a motor and a serious power robber. Whats your cranking compression? What info do you have on the motor build thats for sure?
I think based on the info you have about the motor and times you have run, you very well could be leaving a little (or a lot) on the table, performance wise. A stout 468 could easily put you well into the low 11's, I think it's time to dig into the motor and find out what it is before any changes are made, anything you can find out is a plus.

Cranking compression is 185-189 except for one cylinder. #5 is about 145-155.

[68rs406]

Thats high but not that high, what is your timing etc. set at? sounds like maybe just tuning issues that need to be worked out maybe.

[mkpatrick]

Originally Posted by 68rs406

Thats high but not that high, what is your timing etc. set at? sounds like maybe just tuning issues that need to be worked out maybe.

Yeah maybe, one thing I have to over come is finding a timing pointer that will work on my car.
I have a timing cover that bolts to the block with allen head bolts that are recessed into the cover.
No after market or store bought timing pointer works. I've even tried filing them off on one hole to make it fit and no dice.

Once I over come that, I could probly get an idea of where to time it besides by ear. Of course that would also entail buying a timing tape, I bought one by MSD but it lasted about 3 minutes after I started the motor and came right off.

Any idea how to deal with this timing pointer issue? The timing cover, (don't know the brand) is a polished stainless one, it doesn't look chrome and it has allen head screws that are recessed into it.

[68rs406]

Hmm, thats weird. I can't imagine a timing cover without a provision for a pointer, I imagine the mfg had an idea but a lot of good that does you now I guess.
You definitely need to nail down the timing first, you might try using the old coat hanger trick like if you were degreeing the cam, just a bent piece bolted to any available bolt hole, get true TDC identified and set it with the wire pointer, it would work good once at least, obviously after driving the "pointer" would lose it's accuracy, but you'd have a baseline at least to tune.
As for the timing tape, they can be made to stick, you just have to have a 100% grease free surface, a little brake clean and then a bit of laquer thinner, then apply, it will stay if it's clean and prepped.
That is interesting about the cover though, odd.

[mkpatrick]

Originally Posted by 68rs406

Hmm, thats weird. I can't imagine a timing cover without a provision for a pointer, I imagine the mfg had an idea but a lot of good that does you now I guess.
You definitely need to nail down the timing first, you might try using the old coat hanger trick like if you were degreeing the cam, just a bent piece bolted to any available bolt hole, get true TDC identified and set it with the wire pointer, it would work good once at least, obviously after driving the "pointer" would lose it's accuracy, but you'd have a baseline at least to tune.
As for the timing tape, they can be made to stick, you just have to have a 100% grease free surface, a little brake clean and then a bit of laquer thinner, then apply, it will stay if it's clean and prepped.
That is interesting about the cover though, odd.

The coat hanger is a great idea, I'll look into something like that.

Thanks,