Cam Choice

Witch of these 290-08R , 284-88R would have more lower rpm torque with
455 Bored 30 over with 10.7 compression
TA se heads
TA all. intake and 800 Q-jet
roller lifters
1.6 roller rockers
headers
4 speed Thanx fellas

 

Not to make a simple question difficult...exactly what rpm range are you calling 'low rpm'?
It's tough with a 4 speed to consider flat footing it at 2000 rpm with performance or acceleration in mind.
With better heads as you specify, the midrange doesn't suffer with a slightly bigger cam

 

I don't know if there is a difference when applying DCR to roller cams compared to flat tappet but I can't see not being able to run 10.7 compression with either of those rollers especially with aluminum heads. TA recommends 10:1 minimum with the 290 and 10.5:1 with the 284. What you have to decide is low speed tractability. The 290 with 112* LSA will idle and run smoother than the 284 at 108* LSA. So at 2000 rpm and the clutch engaged the 284 could be a little shaky at light throttle cruise. However with the tighter LSA the 284 is going to come on noticeably stronger in the midrange than the 290. Both will have a noticeable lope at idle with the 284 even more than the 290.

As mentioned hopefully you're not thinking about WOT blasts down at the 2000 rpm level because that will cause problems no matter what cam you have. Maybe from a slow roll in 1st gear would be ok at 2000 rpm but not in a higher gear. With the stick IIRC they do recommend a slower timing curve to keep ping away, maybe full advance at 3500 rpm or so. A torque converter can make life easier when picking a cam.

Also, hopefully your pistons have valve reliefs in them because of the cam lift involved.

 

Back in the day,1978 or 79.. I had a 73 pontiac bird with 455 4 speed and my brother had a 72 skylark 455 4 speed, i always liked the way that that skylark would be at 1800 rpms in 2nd gear and you could push the fuel pedal down kinda slowly and when the secondaries started to open about 28 to 33oo rpms the good sized tires would start to spin and you would have to shift. i think the pont. had 3.23 rear and lark had 3.42 ... almost the same.
Of course the tires are alot better now, But we would look at each other and say what a machine ! I hope ya know what i am tring to get.
Soooo, If i could get a 290 with 110* or 108* that would do it or not so much? Not sure what that will effect. Thanx

 

Why are you considering a low end torque engine with those heads and 10.7 compression?
Even if you have way more cam than that you'll have a ton more at the bottom of the powerband than a mild engine.
That thing has beastly potential.
As soon as you open the throttle it will be serious.

Sounds like your Pontiac had a serious restriction to the carb's secondaries opening rate.

 

Oops! This one's a roller. The 288 is bigger than the 290.
I didn't check the seat to seat opening and closing specs or account for slight installed position changes but these cams could have the same DCR, meaning the intake valve might close comparatively close.
Neither of these are that big for a 455 and won't lack torque anywhere.
The 288 is quite a bit more aggressive, and the specs suggest it wakes up much stronger despite a bit more intake duration.
It should be more intense in the entire street rpm range, with the only potential weakness being the 112 'might' hang on longer...after peak hp.
(dyno tests taken with caution as they might not have headers and other aspects similar to yours. Header specs being important to cam overlap)
The thing about overlap (108 vs 112) is that it's supposed to pull more intake charge in via pulling on the intake tract earlier in the engine's rotational cycle.
VE should be higher, more in the cylinder...more torque.
Where it 'might' be weaker is at idle and slightly above...and then all hell breaks loose and it rips.

 

So the less overlap the sooner it opens intake or , i'm not sure how that works or go about picking a suitable cam.
Your going to laugh,Well, i want it to idle smooth and have gobbs of low end torque. Don't care to go obove 5900 rpms , or faster than 110 or so..

" On that pontiac " And you know i remember messing with that secondary spring that long ago.. i now think it was the hanger or something was to small.. Ha.

So what cam do ya all think is a good choice, one of those or something else?

 

Hello, just a general cam question, ive read on the forums buick 455s run better with a split pattern camshaft, but I noticed a lot of them are the same int and ext lift or very close as well as the duration being very similar on some of what id call the middle tier cams like 2000rpm-6000rpm range, and shouldnt the intake have the higher lift and the exhaust more duration ?. What would be wrong with something like a 505/485 lift 227/235 dur @.050 on a 110-112 lsa ?, or 520/500 on the lift, I think one of the VooDoo cams has specs like this, and a couple of the Howards Rattlers are close but no TA cams, there must be a reason TA dosent make it, anybody know why. it seems like when I get in the area of the duration I think I want the lift gets to extreme or drops to low

 

Are you having a street/strip port job on the aluminum heads ? When mine were ported years ago we ended up bench flowing the heads to get the numbers. Then had a custom ground cam built by Bullit cams to compliment the heads.

 

Ive not done anything with the heads yet and I realize stock ones need more flow, and im talking about a hyd flat tappet cam, I guess what im trying to find out is if TA and Crower specialize in cams for the 455 why dont they make a grind like that because it seems like it would be pretty decent. Maybe the cam bearing size/lobe shape or something odd like that or maybe its just that the ones they have are just that good. they Prob went on to rollers and just left the flat tappets alone cause there good enough I guess. But im still curious why no cam grind in that range

 

Thanks for your reply, thats kinda the conclusion im coming to, first airflow, airflow, airflow then pick a cam according to my cars purpose/operating range, and then go one cam smaller lol

Thanks