Cam Specs - and other

[Mechcanic]

Hello All,
I am new here as a poster, been reading for while. All started with the very long "128 Cam spec revealed." I was really hoping to read the follow up post David Vizard mentioned regarding Cam timing, but the topic was locked from further posts. I searched through the forums trying to find more on the subject but did not have any luck.

So, my project is for a 1971 Chevelle. I bought a very low mileage Gen VI complete Vortec 7400 clean cross hatch and the balance of the engine is in excellent condition and is the base for my new engine build. I have read David Vizards "How to build max performance on a budget" cover to cover many times for good general guidelines and really like the build spec for "Build 7 496 EFI" Here is an abbriviated PM I sent to David and he suggested making a forum topic.

"Hello David,
I really enjoyed the massive details contained within the entire book and appreciate you sharing the info. I also read through the extensive thread here "128 spec revealed" and wanted to thank you for spending so much time responding I was disappointed that it became locked as I was looking forward to your piece on cam timing.

Anyway, back to my question. I would like to build/copy that build 7 from your book. I like the specs and it will fit within my budget and my 1971 Chevelle SS. From the build you stated you used a crane cam at 236/240 .692/653 lifts.

Could you tell me the crane part number for this cam? and if you set the cam timing straight up? Was it a hydraulic roller? I plan on using one, would this be a good idea?

Also, and I may have missed it somewhere in the reading why did you go 1:93 and 1:79 rocker arms. I know this will generally make a smaller cam bigger, but wondered if your lift information was with the rockers used.

I am starting with a Gen VI untouched block from a 1999 bus. It only had 65,000 miles on it (wreck) and is in excellent condition. The crosshatching is still there and almost the way GM made it. I am planning on following all your advice and hope it will give me good vacuum and idle quality. I am putting a 4l80E behind it and run it through a ford 9" with 3.50 or 3:73 gears. We have many roads in Michigan that are 75mph so I would like a decent rpm at cruise.

I appreciate your reply. Any assistance/suggestions you care to offer will be greatly appreciated."

So Guys,
I doing a frame off restoration and plan on getting the engine and drive line installed once the frame is back from powder coating. Missing above my tires are 28" would like cruise rpm around 2200 and an engine that will have good idle, run on 93 octane, and decent vacuum. These are the qualities that are mentioned in the book with HP and Torque where I believe will suit me well. Other details:
EFI system undetermined
Edelbrock e-street heads
10.5 - 11.0:1 compression
cam mentioned above
port injection intake with 1200cfm throttle body
internal balance
wiseco pistons
forged crank and rods (scat)
hooker headers with 2" primary's
3" magna flow duel exhaust

Trying to stay around a 2000 - 2200 stall torque converter.

If there is any advice that anyone could give me I'd appreciate it. I have rebuilt many Fords, but this will be my first Chevy, so while familiar with engine tech, I am green with BBC's

Thanks Everyone, looking forward to conversing with all of you!
Paul

[GARY C]

Just FYI, I have known DV for 10+ years and have found that I am more likely to get a reply from NASA than from David via email or PM, his inbox looks like most peoples spam box so only a hand full of top priority gets dealt with.

128 is for small blocks, I think he derived at 132 for BBC but don't hold me to that.

He orders cams based on his own specs so there would be no part number for the cam you mentioned, you would have to find those lobes in Cranes lobe list and order accordingly.

I don't have his BBC books only some chapters he has sent me on BBC book 2 but based on the spects and most of his builds I would guess hyd roller.

The rocker ratios you gave sound like the actual ratios of the Scorpion 1.8 and 1.7 that he does a detail chart on multiple rockers in his BBC 2 book. as for cam lift specs on the specific cam again you would have to look at the Crane lobes, my guess is based on the specs they are factoring in the higher rocker ratio.

Hopefully some guys here with BBC/EFI experience will chime in on your combo and share what they have found to work. If you are going to try to follow what DV does I would suggest getting both book 1 and 2 and match what he does or go with someone else and match what they do but if you try to combine parts and pieces from different approaches you will most likely have a bunch of mis matches components that will probably cause you to end up blaming your poor results on the ones you took info from but applied it as you chose.

[bobmc]

I guess you need an ECU that does transmission control, Does the 1999 engine have a knock sensor?

[Mechcanic]

Just FYI, I have known DV for 10+ years and have found that I am more likely to get a reply from NASA than from David via email or PM, his inbox looks like most peoples spam box so only a hand full of top priority gets dealt with.

128 is for small blocks, I think he derived at 132 for BBC but don't hold me to that.

He orders cams based on his own specs so there would be no part number for the cam you mentioned, you would have to find those lobes in Cranes lobe list and order accordingly.

I don't have his BBC books only some chapters he has sent me on BBC book 2 but based on the spects and most of his builds I would guess hyd roller.

The rocker ratios you gave sound like the actual ratios of the Scorpion 1.8 and 1.7 that he does a detail chart on multiple rockers in his BBC 2 book. as for cam lift specs on the specific cam again you would have to look at the Crane lobes, my guess is based on the specs they are factoring in the higher rocker ratio.

Hopefully some guys here with BBC/EFI experience will chime in on your combo and share what they have found to work. If you are going to try to follow what DV does I would suggest getting both book 1 and 2 and match what he does or go with someone else and match what they do but if you try to combine parts and pieces from different approaches you will most likely have a bunch of mis matches components that will probably cause you to end up blaming your poor results on the ones you took info from but applied it as you chose.

Hi Gary,
Thanks for the reply. From the "128" post you are correct, he uses 132 for the BBC cams. I am not concerned with that so much, since in his book DV mentions the cam as I stated, but lacking the LC. I do agree it is a Hydraulic Roller but he didn't state it. If I am correct, any cam made custom or not would have a part # but I cannot be sure since I have never ordered a custom cam before. Hopefully DV will comment, but I am open to any suggestions or information from others whom have BBC EFI knowledge. I was not aware of a second DV book but will look for it. My daughter bought me the first book for Christmas.

Right now I do have the complete GM Vortec system from the MAF to the injectors. I would consider keeping the entire system and getting a OEM ECU reprogrammed. There is little information about performance capabilities of the stock system, so I am a little blind here. If I use the GM ECU it includes the trans controller with it.If not I would get the EFI and trans controller from the same company.

It is my intention not to make a hodge podge mix of suggestions so I surely take your heade your warning. Just to clarify to everyone, I am working on the parts list, the only items I actually have are the entire exhaust system and complete vortec engine. I like the parts I listed but am wide open for suggestions. I like the 496 stroker combo because it should be minimal work to install (relieving the block, etc) and will cost little more if any than a stock 4.00 crank.

[Mechcanic]

I guess you need an ECU that does transmission control, Does the 1999 engine have a knock sensor?

Hi Bob, the stock EFI system does have a knock sensor. I wrote more info in my reply to Gary.

Thanks,
Paul

[Orr89rocz]

You could entertain the ls1 0411 pcm swap. Efi connection sells parts to allow a reluctor ring under the timing cover and a 1x cam sensor distributor. That way you can also use ls1 coil packs and still control oem tranny that way.

Could possibly start with the 96-99 truck harness for the bbc and repin to a 0411 connector or start with a ls1 harness and cut/move stuff around to fit as needed

I used the 0411 on my sbc.

Other option would be to go tbi injection like the early 90’s trucks and swap to a 7427 pcm with 80e trans control built in but i agree port injection is much preferred

Or go holley hp efi

[David Vizard]

Paul,

I very rarely use a catalog cam for my builds because, for the most part, they leave too much on the table. For instance , a short while back I did a cam for a 540 that powers one of the cars used on the TV show featuring street racers. It did drop 12 HP over the cam being used but on the plus side bumped up peak torque by (as near as I remember) 60 lbs-ft on peak torque and as much as 100 lbs-ft elsewhere in the power curve. The result was a very measurable reduction in ET and a substantial increase in trap speed.

When I spec out a cam I treat every engine as a unique deal. This means the engine gets the cam that best sits the clients engine and no other unless it happens to be otherwise identical.

Paul, Let us do this. Send me the following details and I will spec out a cam for you.

Here is what I need:-

Bore ---------------------
Stroke -------------------
CR -----------------------
Rod length--------------
Rocker ratio in.--------
Rocker ratio ex.-------
Fuel Octane used ----
Head type/casting #-
Intake valve size-----
Exhaust valve size-----
Flow figs at 0.050, -0.100, -0.150,- 0.200, 0.300, 0.400, 0.500, 0.600, 0.700 & 0.800.
The most important ones are the low lift one 0.050 to 0.200.
If you do not have them I may have them as I have flow tested almost every stock factory head out there.
Peak Power RPM-----
Idle Vac Required ---
Intake manifold End carb to be used.
Header dimensions --
Intended applications --

DV

[David Vizard]

Gary wrote:- Just FYI, I have known DV for 10+ years and have found that I am more likely to get a reply from NASA than from David via email or PM, his inbox looks like most peoples spam box so only a hand full of top priority gets dealt with.

128 is for small blocks, I think he derived at 132 for BBC but don't hold me to that.


Gary, Thanks for putting my position in front of the readers here. You nailed the situation in your own near unique way.

I was on the phone too one of the guys at Dart for about 40 minutes and during the time over 90 emails came in. If I went full time answering legit emails as apposed to spam they would still come in far faster than I can respond to them. Gary - In your case you are a very patient guy - thanks for understanding.

As Gary pointed out the cam calculation constant applies only to one specific engine. For instance - 127 for SBF - 128 for SBC and 132 for BBC. There's more in the works.

[Nick Campagna]

Hello All,
I am new here as a poster, been reading for while. All started with the very long "128 Cam spec revealed." I was really hoping to read the follow up post David Vizard mentioned regarding Cam timing, but the topic was locked from further posts. I searched through the forums trying to find more on the subject but did not have any luck.

So, my project is for a 1971 Chevelle. I bought a very low mileage Gen VI complete Vortec 7400 clean cross hatch and the balance of the engine is in excellent condition and is the base for my new engine build. I have read David Vizards "How to build max performance on a budget" cover to cover many times for good general guidelines and really like the build spec for "Build 7 496 EFI" Here is an abbriviated PM I sent to David and he suggested making a forum topic.

"Hello David,
I really enjoyed the massive details contained within the entire book and appreciate you sharing the info. I also read through the extensive thread here "128 spec revealed" and wanted to thank you for spending so much time responding I was disappointed that it became locked as I was looking forward to your piece on cam timing.

Anyway, back to my question. I would like to build/copy that build 7 from your book. I like the specs and it will fit within my budget and my 1971 Chevelle SS. From the build you stated you used a crane cam at 236/240 .692/653 lifts.

Could you tell me the crane part number for this cam? and if you set the cam timing straight up? Was it a hydraulic roller? I plan on using one, would this be a good idea?

Also, and I may have missed it somewhere in the reading why did you go 1:93 and 1:79 rocker arms. I know this will generally make a smaller cam bigger, but wondered if your lift information was with the rockers used.

I am starting with a Gen VI untouched block from a 1999 bus. It only had 65,000 miles on it (wreck) and is in excellent condition. The crosshatching is still there and almost the way GM made it. I am planning on following all your advice and hope it will give me good vacuum and idle quality. I am putting a 4l80E behind it and run it through a ford 9" with 3.50 or 3:73 gears. We have many roads in Michigan that are 75mph so I would like a decent rpm at cruise.

I appreciate your reply. Any assistance/suggestions you care to offer will be greatly appreciated."

So Guys,
I doing a frame off restoration and plan on getting the engine and drive line installed once the frame is back from powder coating. Missing above my tires are 28" would like cruise rpm around 2200 and an engine that will have good idle, run on 93 octane, and decent vacuum. These are the qualities that are mentioned in the book with HP and Torque where I believe will suit me well. Other details:
EFI system undetermined
Edelbrock e-street heads
10.5 - 11.0:1 compression
cam mentioned above
port injection intake with 1200cfm throttle body
internal balance
wiseco pistons
forged crank and rods (scat)
hooker headers with 2" primary's
3" magna flow duel exhaust

Trying to stay around a 2000 - 2200 stall torque converter.

If there is any advice that anyone could give me I'd appreciate it. I have rebuilt many Fords, but this will be my first Chevy, so while familiar with engine tech, I am green with BBC's

Thanks Everyone, looking forward to conversing with all of you!
Paul

Can you give the url ? Search does not work with "128 Cam spec revealed".
Thanks

[GARY C]

https://www.speed-talk.com/forum/viewtopic.php?t=45639
Here is one, I couldn't find part 2

Found it!
https://www.speed-talk.com/forum/viewtopic.php?f=1&t=46038

[FC-Pilot]

Paul, I will not try to but in and give specifics on the engine or cam stuff for your combo as others have more experience in that department than I. What I will share is that you probably do not want a 2000-2200 stall converter. I feel you would be best with a 3000-3500 stall converter, but that utilizes the lock-up capabilities of the transmission and controller. That way you will have the best of both worlds. It will stall higher when needed, yet cruise while locked up at a lower RPM. Anyway, just my two cents.

Paul

[Mechcanic]

Paul,

I very rarely use a catalog cam for my builds because, for the most part, they leave too much on the table. For instance , a short while back I did a cam for a 540 that powers one of the cars used on the TV show featuring street racers. It did drop 12 HP over the cam being used but on the plus side bumped up peak torque by (as near as I remember) 60 lbs-ft on peak torque and as much as 100 lbs-ft elsewhere in the power curve. The result was a very measurable reduction in ET and a substantial increase in trap speed.

When I spec out a cam I treat every engine as a unique deal. This means the engine gets the cam that best sits the clients engine and no other unless it happens to be otherwise identical.

Paul, Let us do this. Send me the following details and I will spec out a cam for you.

Here is what I need:-

Bore ---------------------
Stroke -------------------
CR -----------------------
Rod length--------------
Rocker ratio in.--------
Rocker ratio ex.-------
Fuel Octane used ----
Head type/casting #-
Intake valve size-----
Exhaust valve size-----
Flow figs at 0.050, -0.100, -0.150,- 0.200, 0.300, 0.400, 0.500, 0.600, 0.700 & 0.800.
The most important ones are the low lift one 0.050 to 0.200.
If you do not have them I may have them as I have flow tested almost every stock factory head out there.
Peak Power RPM-----
Idle Vac Required ---
Intake manifold End carb to be used.
Header dimensions --
Intended applications --

DV

Hi Dave,
Here is what I have and thank you in advance for your generous time. I am certainly open for any tweaks - a couple of extra notes - 3.50 dif. 4L80e trans - looks like I may have to revisit my 2000 - 2200 stall converter thoughts.

Bore --------------------- 4.310
Stroke -------------------4.250
CR -----------------------10.8 – 11.0:1
Rod length--------------6.375
Rocker ratio in.--------Might use the scorpion ratios in your build 7 (496 EFI) or BBF 1.73 I am open for suggestions
Rocker ratio ex.------- Might use the scorpion ratios in your build 7 (496 EFI) or BBF 1.73
Fuel Octane used ----93
Head type/casting #- TFS 280’s
Intake valve size-----2.25
Exhaust valve size-----1.88
Flow figs at 0.050, -0.100, -0.150,- 0.200, 0.300, 0.400, 0.500, 0.600, 0.700 & 0.800.
The most important ones are the low lift one 0.050 to 0.200. I got this from Super Chevy Oval port article – I am using oval port heads they didn’t have .800 lift numbers
Lift In EX
.050 32 30
.100 67 62
.200 143 122
.300 212 160
.400 266 189
.500 302 221
.600 328 244
.700 337 261

If you do not have them I may have them as I have flow tested almost every stock factory head out there.
Peak Power RPM-----6400
Idle Vac Required ---12 – 14 like to run power brakes not sure how much idle vacuum would be needed.
Intake manifold and carb to be used. EFI system port injection 1000 - 1200 cfm throttle body with a mega squirt or other controller looking at port efi intakes but have not decided.
Header dimensions – 2” primary 3.5” collector Flowmaster elite series
Intended applications – Street performance - cruising

Thanks again David. Other mentioned a second bbc book you wrote. What is the title?

[Mechcanic]

Paul, I will not try to but in and give specifics on the engine or cam stuff for your combo as others have more experience in that department than I. What I will share is that you probably do not want a 2000-2200 stall converter. I feel you would be best with a 3000-3500 stall converter, but that utilizes the lock-up capabilities of the transmission and controller. That way you will have the best of both worlds. It will stall higher when needed, yet cruise while locked up at a lower RPM. Anyway, just my two cents.

Paul

Hi Paul,
I appreciate any thoughts. I was a little concerned about overheating with the converter slipping in town - cruising and do realize that 2000 stall is on the low side. I kinda thought the 496 would take care of that due to the high torque it should have. Do you think it will present an issue? I am definitely planing a locking type, so I do understand where you are coming from. I'd like to install T56 magnum, but hate the idea of cutting the floor out to accommodate it. If anyone has any thoughts on that I'd really like to hear. I do have an LS1 T56 but was told the 496 will eat it.

[Mechcanic]

https://www.speed-talk.com/forum/viewtopic.php?t=45639
Here is one, I couldn't find part 2

Found it!
https://www.speed-talk.com/forum/viewtopic.php?f=1&t=46038

Thanks Gary, I'll read through it. Appreciate the help!

[Nick Campagna]

https://www.speed-talk.com/forum/viewtopic.php?t=45639
Here is one, I couldn't find part 2

Found it!
https://www.speed-talk.com/forum/viewtopic.php?f=1&t=46038

Thanks
Nick