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BBC CAM SUGGESTIONS

16K views 45 replies 27 participants last post by  69camaro 
#1 ·
I have a 468 in a 3500lb camaro,400 turbo with a 4200 stahl, 4.30 gears.I recenntly changed from iron 049 heads to a set of Dart Pro 1 (310'S) with roller set up. Was running flat tappet solid previously with 638 lift and 270/280 duration. Car went 10.40 with 1.42 60ft, since changing to roller set up and new heads I purchased a cam from Comp Cams with 660/666 lift and 254/260 duration (I used thier online cam suggestion link). The car has gone a best of 10.55 with the 60ft still in the mid 1.40's. i was expecting a big difference with weight lose, changing from oval to rect. port, and roller. What cam set up should I have picked? oh yeah motor is 12.5 comp.,1050 dominator, suspension is cal tracs springs and bars.
 
#2 ·
You need more duration with the bigger heads, not less. And also go for more lift if your springs can take it. If you like Comp, 11-734-9 would be a much better choice (276/284; 0.748/.714"). Never listen to Comp's recommendations without seeking other sources to verify what they tell you.
 
#8 ·
You need more duration with the bigger heads, not less. And also go for more lift if your springs can take it. If you like Comp, 11-734-9 would be a much better choice (276/284; 0.748/.714"). Never listen to Comp's recommendations without seeking other sources to verify what they tell you.
Not unless your increasing the RPM Doc.....

Also the more rocker arm or valve lift means for the same RPM range less duration at .050"
 
#4 ·
In most cases, big port heads and bigger cams need the engine to spin faster to take advantage of them. I do agree with rskrause that the cam you have now is too small. What is critical in the heads is port speed. Going to the Pro1's, some of that speed was lost Vs the oval port heads you took off.

How much work was done to the oval ports ?
 
#6 ·
The mentioned cam would work better for sure... There is a .748 .748 available too, pretty sure...

I'd do 272 - 278 at .050 .. do a 110LSA and install at 108IC... With the weight of your rig, you'll jump hard outta the hole... and you'll have the lift to pull the topend.. with the moderate duration.

My 2.

Good luck.
 
#12 ·
With the lower compression 274/281 w/ at least a .440 lobe with a 106 ICL.

You are headed the wrong way with gear. You need more not less. You don't have enough inches to utilize either, unless of course this is not a full time race car.
Heavy car needs converter and gear to get out of the hole.
 
#14 ·
I think the head size is about right for the cid. I would change to a larger cam, as much lift as the piston to valve clearance will allow, dur in the .278-.284 range and taller gears. I also think more converter and gear is needed unless your gonna spray it. Might work well with some juice but n/a will need more rpm's out of the hole. This is just my opinion though.
 
#18 ·
Did you flow your heads? If not, you're throwing darts at a dart board and leaving plenty on the table with off the shelf stuff. I did a 12.4:1 467 quite e few yers ago with some Canfield 310's that honestly, I went backwards with on the flow, but with the flow numbers and build specs, I had Chris Straub spec a roller for it, and with a TR and pair of 1050's it made 821 @ 7100, 680 @ 5500, and had a very flat curve. Here's the kicker...the cam was 717/663 261/266. Not much of a cam for the power. No need to scream the engine to make good power.
If you want the most out of your combination, flow the heads and get the right cam.
JMO
 
#20 ·
like scott said^^^^^^ it 's the ONLY WAY!! comp cams would be one of the last i called. theres intake valve timing, exh valve timing, lifter of the cam and profile i.e how fast the lift accelerates this is why no two cam will ever make the same power unless there form the same company ground the with the all same spec.
 
#21 ·
Here is what I would do;

1) Degree cam - VERY IMPORTANT
2) Measure ACTUAL compression ratio, you are probably lower than you think
3) Flow heads
4) Select proper cam for combination
5) Make sure torque convertor and axle ratio match accordingly
 
#24 ·
Pulling the motor this coming weekend . Car ran excellent with the 270/280. I screwed up with the roller selection thinking the steeper lift angle made the valve full open quicker so not as much duration was needed. Thats why I didn't question Comp Cams online selection.
 
#26 ·
Intresting Thread , I too have a 3800+lbs car with a 454 with too big Dart Race Series 320's and a cam with less than .600 lift and 245-250* of duration. I know I do Have a Honest 12 to 1 comprerssion tho. I am looking at this winter going too a bigger roller and was recommended 274*/278* .435 .435 LL on a 108 and if there is room and Cash I want to go to a rocker shaft . I Have 28 inch tall tires and a 4.56 gear all I need is a new Convertor to match the rest of the set up
 
#40 ·
Intresting Thread , I too have a 3800+lbs car with a 454 with too big Dart Race Series 320's and a cam with less than .600 lift and 245-250* of duration. I know I do Have a Honest 12 to 1 comprerssion tho. I am looking at this winter going too a bigger roller and was recommended 274*/278* .435 .435 LL on a 108 and if there is room and Cash I want to go to a rocker shaft . I Have 28 inch tall tires and a 4.56 gear all I need is a new Convertor to match the rest of the set up
See I was on the wrong path I right now have a set of 049's going to gether And I am Calling LSM and Saying " Give me the Ed B. Cam!" If it worked for him it will work for my Car I am just going to use his recipe
 
#27 ·
look into the Comp 11-702-9...its a great piece that is easy on valve springs..

271/282 with .680 lift on 110 LSA...

i will be on the dyno with this cam in about a week in a 522..i will let you know how it turns out...

there is also the old Crane standby, 274/284 with .737 int and i cant remember on exhaust...on 110..also easy on springs and makes great TQ and HP...IIRC #134751...

i personally would not go over 274 on intake...
 
#29 ·
Something I forgot to ask, I'm running 2, 08an lines from cell to y-block then to mallory 180gph pump then a single 1/2 fuel line to regulator on fire wall with (2) 06an lines to each bowl on a dominator,(1050) . I do not have it set up to return it dead heads at carb. Queastion is : is it better to have a return setup also is line size large enough for engine.:confused:
 
#30 ·
I think your cam is fine for your application. Degree it and put the intake centerline at 106*. You dont need big duration with those heads as their ports are slower than your oval ports. Going with a bigger duration cam than what you have will destroy what little low to midrange torque you have.
 
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