BBC thoughts

[RevTheory]

This is the correct chart. Is this the one you used?

BBC Overlap Chart.png

[prairiehotrodder]

yes thats the chart however my book doesn't have that paragraphs underneath. I came up with 93 by using 555 cubes at around 7250 rpm. As the paragraph says its not dead on and other factors come into play such as CR and low lift flow. You tell me what DV would suggest for my current motor.

2.3 intake valve
540 cubes
9.9 CR
AFR 335 CNC heads (all flow numbers are on their website)
car crosses the line at around 7200 rpm.

[GARY C]

yes thats the chart however my book doesn't have that paragraphs underneath. I came up with 93 by using 555 cubes at around 7250 rpm. As the paragraph says its not dead on and other factors come into play such as CR and low lift flow. You tell me what DV would suggest for my current motor.

2.3 intake valve
540 cubes
9.9 CR
AFR 335 CNC heads (all flow numbers are on their website)
car crosses the line at around 7200 rpm.

Then shouldn't you be looking for peak power at about 6700 rpm?

[GARY C]

This is the correct chart. Is this the one you used?

BBC Overlap Chart.png

Is this the updated chart that did not get put in the book?

[RevTheory]

yes thats the chart however my book doesn't have that paragraphs underneath. I came up with 93 by using 555 cubes at around 7250 rpm. As the paragraph says its not dead on and other factors come into play such as CR and low lift flow. You tell me what DV would suggest for my current motor.

2.3 intake valve
540 cubes
9.9 CR
AFR 335 CNC heads (all flow numbers are on their website)
car crosses the line at around 7200 rpm.

Just checking because there was a "whoopsie" on the chart when his book first came out.

Off the top of my head? 268/274 at .050, 106 LSA (ish- give or take a few on duration and hopefully that's enough to start nosing over at the stripe) but I wouldn't run that on 9.9:1 compression. I'd either cam down to match the existing compression or up it to make the combo right at 7,000+ rpm. But you know what they say about opinions...

Again, that's just right off the top of my head. Sniper Jr. and a 4500 too.

[MadBill]

Beyond DV's chart is of course his complete COS cam program..

[F-BIRD'88]

Look up the Difference in the weather data currently right now at Saskatoon,,, Memphis and Winnipeg BIG different note the uncorrected Barometer pressures and temperature.

Memphis and Winnipeg is going to dyno and track test run very similar

Saskatoon is NOT. It is a lot different. (especially today) And it is going to be a lot less power today
and at least some LESS power every day than the other locations.
This may be why you seem to be able to get away with a higher cr than me....
My air is always better air most of the time and it is hotter here to most of the time.

[F-BIRD'88]

I came up with 93 by using 555 cubes at around 7250 rpm

The car crosses at 7200

You are using the chart wrong.

you have to run the car higher than the Peak HP rpm point a the end of the 1/4..
A LOT higher if when the trans is a glide and the car is heavy.

So you'd need to gear it to trap at about 7800rpm.
you are not so tame the overlap
You also don't have 14:1cr so again tame the overlap and or advance the cam.

But of you are going to trap at 7200 rpm then pick the cam overlap for about 6600rpm
THEN ALSO correct for the lower compression ratio (and or advance the cam)

[F-BIRD'88]

If you ultimatly want to end up with a fast car the STraub cam was worth more in your hand
So you can test and compare car performance or even dyno performance
with it to compare against any new cam Straub or different to see if the new cam is
ACTUALLY better.. You have 2 good BASE LINE CAMS
They both run good.

You can by another cam "the perfect cam" or.... 10 more cams
You will NEVER actually know if that new "better" cam is actually better
on the dyno and or in the car where it actually counts
UNLESS and UNTIL you Test and compare it to ANOTHER cam.
You should have kept that cam whether working with the current motor
or a different 555 BBC w 11.5:1cr
That was a bad choice if you want to end up with a fast car.

[prairiehotrodder]

Electric water pump, electric fan are now on the car and the cam is in at 103 ICL from 108. Good September air is coming soon.
Looked at a couple tunnel rams today. The Weiand and the Edelbrock Victor are my main 2 choices. The Eddy looks to have shorter, straighter ports while the Weiand is taller more curved. The Weiand is also cheaper.
Brian

[statsystems]

Electric water pump, electric fan are now on the car and the cam is in at 103 ICL from 108. Good September air is coming soon.
Looked at a couple tunnel rams today. The Weiand and the Edelbrock Victor are my main 2 choices. The Eddy looks to have shorter, straighter ports while the Weiand is taller more curved. The Weiand is also cheaper.
Brian

You do realize a TR takes a different cam than a single 4 right?

[prairiehotrodder]

are you teasing me? If i change the tail lights it requires a different cam.

[Old School]

Electric water pump, electric fan are now on the car and the cam is in at 103 ICL from 108. Good September air is coming soon.
Looked at a couple tunnel rams today. The Weiand and the Edelbrock Victor are my main 2 choices. The Eddy looks to have shorter, straighter ports while the Weiand is taller more curved. The Weiand is also cheaper.
Brian

You do realize a TR takes a different cam than a single 4 right?

What will be different? If I have a cam with .740 lift, 270-280@ .050 110 lobe separation what will the tunnel ram cam specs be?

[cgarb]

271/281 @.050...lol

[RevTheory]

I've heard that a dozen times on here but I've yet to hear a single person say what needs to be changed.