Comments? BB cam choice
Thread Starter
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
Comments? BB cam choice
I'm playing around with some cam choices for my 427 and value the opinion of other forum members. Here's what I'll have:
"990" LS-7 iron heads, cleaned up and port-matched, Manley Stainless valves, 1.5" Manley valve springs, 140 lbs seat press. @ 1.92" installed height.
stock 435 HP 3x2 manifold with re-jetted carbs (if needed).
Stock lower end (10.25-1 compression) for now.
Headers (Heddman side exit, possibly Stahl side exit if funding allows).
Cam numbers looking something like this:
Flat tappet (solid)
Duration 230 @ .50 exhaust, 240 @ .50 intake
Lift around .600
112-116 lobe centers
Cam timing straight up for now
I want to road-race this car and need the power to come on fairly easy down low (no snap spins!) and then pull like gang-busters from 3K to, say, about 7K. Thoughts?
Hans
"990" LS-7 iron heads, cleaned up and port-matched, Manley Stainless valves, 1.5" Manley valve springs, 140 lbs seat press. @ 1.92" installed height.
stock 435 HP 3x2 manifold with re-jetted carbs (if needed).
Stock lower end (10.25-1 compression) for now.
Headers (Heddman side exit, possibly Stahl side exit if funding allows).
Cam numbers looking something like this:
Flat tappet (solid)
Duration 230 @ .50 exhaust, 240 @ .50 intake
Lift around .600
112-116 lobe centers
Cam timing straight up for now
I want to road-race this car and need the power to come on fairly easy down low (no snap spins!) and then pull like gang-busters from 3K to, say, about 7K. Thoughts?
Hans
Last edited by Wrencher; Feb 23, 2005 at 06:41 PM.
Racer
Joined: Sep 2000
Posts: 324
Likes: 0
From: Knoxville, Tennessee
The trick is to find a cam with a narrow lobe center, look in the 106-108 degree range. This will take care of some of the low end and give you a nice wide powerband in the mid to upper ranges. Look at cam listings for circle track motors. Don't expect good idle or vacuum from these cams.
Pro
Joined: Oct 2004
Posts: 510
Likes: 5
From: Pipe Creek TX
My '69 427 L-88 vintage car has 12.5 comp. with a 248/258 @ 050 , 110 LS. GM dual plane and a Holley 830.
Dyno's 426 tq @ 2600 rpm ; peak 475 tq @ 5000 rpm . Peak HP 505 at 6400 rpm. Makes the best shift point at 6900 ;which is 368 tq and 477 hp.......
Dyno's 426 tq @ 2600 rpm ; peak 475 tq @ 5000 rpm . Peak HP 505 at 6400 rpm. Makes the best shift point at 6900 ;which is 368 tq and 477 hp.......
Thread Starter
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
Whoa!
Those are very nice numbers! 12.5 to 1 helps a bunch I'm sure. I'm trying to keep it stock appearing as much as possible and not cut it, so there are some major compromises compared to a A/P racecar! Got any pictures?
Hans
Hans
Racer
Joined: Sep 2000
Posts: 324
Likes: 0
From: Knoxville, Tennessee
Compcams and Crane both have tech lines, you might give them a call with your application. Cam Motion in Baton Rouge, LA will also custom grind one for your exact needs. There are alot of choices. A 10.25 CR 427 with any big cam is going to be lacking on low end torque no matter which way you go. There is a reason Chevrolet put a hydraulic cam in 427/400 air cars.
Racer
Joined: Feb 2005
Posts: 317
Likes: 2
From: coral gables miami
Originally Posted by Wrencher
I know it's asking a lot, but I need to keep some vacuum for the headlight/wiper/PB systems. Don't care about a ratty idle, and it's a 4spd, so thats no problem. Thanks.
Hans
Hans
Nice idle at around 850 also.
Last edited by gofastvette; Feb 24, 2005 at 01:25 PM.
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Race Director
Joined: Dec 1999
Posts: 11,094
Likes: 990
From: Sierra Foothills CA
I'd give Harold Brookshire (former owner of Ultradyne Cams) a call- he's w/ Lunati now & has some great grinds to choose from along w/ the experience to get you the right one for your needs. 
Team Owner
Joined: Feb 1999
Posts: 34,453
Likes: 665
From: Republic of Texas
Originally Posted by Les
I'd give Harold Brookshire (former owner of Ultradyne Cams) a call- he's w/ Lunati now & has some great grinds to choose from along w/ the experience to get you the right one for your needs.
Harold is the man.FWIW, I really like my CC 294 solid, I get LOTS of compliments on the idle. I'm still breaking in the car (has < 100miles) but this thing is VERY strong for what I can tell so far.
Pro
Joined: Oct 2004
Posts: 510
Likes: 5
From: Pipe Creek TX
Originally Posted by Wrencher
Those are very nice numbers! 12.5 to 1 helps a bunch I'm sure. I'm trying to keep it stock appearing as much as possible and not cut it, so there are some major compromises compared to a A/P racecar! Got any pictures?
Hans
Hans
The only difference will be your 10.5 comp and closed exhaust. This will result in a decrease of about 10-15 % power . The tri -power might cost 20 HP less , compared to the dual plane. As you can see , this cam works down low.
There's lots of choices out there ; don't get caught up in over analyzing what you need.
I'm right in the middle of paint prep , but can email pictures to you direct if you would like.