cam choice for the 461 poncho

[pontiacpower]

Hello guys. Just wanted to see what any of you indians have used for your poncho motors. Butlers recommend a comp cams xe 268 or 274 for my e85 461 build. Any thoughts. I think thumpin455 might have used one of these in his 70 gto but i cant remember. Ive youtubed both but i havent checked dynos yet.

[DanStokes]

Todd is your guy on this though it's hard to argue against Butler's - they've done this a time or two.

Dan

[fatguyzinc]

most cam recommendations are too small, because they dont want you
to complain about the rough idle, rich smell, poor vacuum, etc...

that being said, i ran the isky 292/.505/108 in my 455 pontiac, with
true 10-1, D port heads that were ported/polished by me, a torker II
intake with a 1" four hole spacer, an 800EPS carb, and roller top end
along with hedman hustler headers and full 2.5 duals with aerochambers,
a 2400 stall and 3.42 gear.

the 66 GTO it was in weighed 3340 and went a best of 11.97@116
on normal 275/50/15 BFG radial T/A's at 18psi, usual runs were 12.00-12.10
at over 114mph....

yes, it idled rough. yes it had low vacuum and needed a canister.
yes it smelled a bit rich at idle. whats not to like?!?!!! its a HOTROD, right?

it ran low 12/ high 11's in full street trim, and was mellow enough that my
mother could drive it to the store--but once you stuck your foot
in it, hang on !!!!!

[cstmwgn]

most cam recommendations are too small, because they dont want you to complain about the rough idle, rich smell, poor vacuum, etc...!!!!!

I agree that you would be leaving a lot on the table going with a 268. A 292 is a bit more than I think you want for your usage BUT if it was a solid so you could use lash to hide duration then that might work. I have been running a 282 solid in my F250 for ~100K. It pulls trailers and is fun to drive when empty. Remember that the more CIs you have the more cam you need to feed the hungry beast. As always, Todd is the Pontiac guru so his advice should probably be followed closely.

[fatguyzinc]

I agree that you would be leaving a lot on the table going with a 268. A 292 is a bit more than I think you want for your usage BUT if it was a solid so you could use lash to hide duration then that might work. .

or use rhoads lifters. or, the next size smaller isky mega-hydraulic
(280-.485-108) as seen here...

https://www.summitracing.com/parts/isk-901281/overview/

either way i would run the highest lift/shortest LC i could
find for any given application, its a recipe that has served me
well over the years.

a short LC does reduce idle quality (ummm...dont you WANT
that "rumpity-rump" idle in a hotrod? i sure do...) and vacuum
(hey, thats WHY they make reserve canisters, or in extreme cases
vacuum pumps...) but it makes the power absolutely explosive,
take a look at the 'sprint' or circle track cams-they usually run
really short 106-104 LC's for that hard hitting power coming off
the corners.

[pontiacpower]

I took a look at that isky cam. That's not too expensive. I don't have a problem installing a vacuum can I suppos. Can't be too hard to get in there. I just want to get the rotating assembly in this block so I can keep it from rusting.

[fatguyzinc]

I took a look at that isky cam. That's not too expensive. I don't have a problem installing a vacuum can I suppos. Can't be too hard to get in there. I just want to get the rotating assembly in this block so I can keep it from rusting.

the 280 probably wont need a canister, but the 292 would.... either one
makes REALLY good power ( we did the 280-.565-108 in another 454
vette 20 years ago, and it went 12.17@112 in full street trim.) and the
iskys have proven to be 30-60hp up over similar grinds from other guys.
(google it if you want.)

i dont own stock in isky, i aint got one to sell you, just in my 30+ years
of building TRUE fast street cars ( not race cars that masquerade as
street cars...) i have found that isky and lunati usually work best for me.

the other cam you might want to consider is the lunati voodoo #4, see here-

http://www.lunatipower.com/Product.aspx?id=2356&gid=287

however-- between the 3 i would run the 292 isky, then the 280
isky, then the voodoo. just my opinion, of course--your car
and your money in the end.

no matter what its going to make good power, even a "normal"/stock cam
should get you 350+hp and 460ftlb easily.
i would expect closer to 475hp and 515ftlb with the 292 isky, and thats
kind of a conservative estimate. those 455 pontiacs make some POWER
when set up right.

and i wouldnt run more than a 3.73 gear with a stick shift, or 3.55
with an auto no matter what cam you run. also no more than 2400 stall.

im absolutely certain no matter which way you go, that motor
will be honkin'.........

[pontiacpower]

I see the 292 mega at summit but is there another 292 that I'm not seeing? And I also need pushrods and valve springs and rockers because all I have is the stock ones off my 350 so I'd like to buy a kit that has it all

[ratpatrol66]

What heads are you running? I have some cast iron heads at SD Performance right now get CNC ported. Can't wait to get them back and installed on my GTO!!!

[fatguyzinc]

I see the 292 mega at summit but is there another 292 that I'm not seeing? And I also need pushrods and valve springs and rockers because all I have is the stock ones off my 350 so I'd like to buy a kit that has it all

if its this guy--
http://iskycams.com/cart/index.php?m...oducts_id=1021
then thats the one. i would shift it between 5400-5800rpm
(think stock redline was 5600, it will tell you what it likes in the ET...)
which is pushing it with that 4.210 stroke, but as long
as you got the "armasteel" rods (i hope) it will be fine.

if you have regular cast rods (at LEAST ARP bolts i hope...
then 5200rpm or so. even a generic 'shift kit' will lay rubber
on that 1-2 shift with a 455 poncho, and the left front fender
will jerk upward 2-3 inches. a 4spd is even worse. fun stuff.

like i said, you almost HAVE to wind up with 350+hp
and near 500ftlb no matter what cam you run...
and any good cam will push that higher.

good pontiac places-nunzi, butler, kauffman, wenzler,
ames performance, or allpontiac.com.

and heres a NICE recipe, check the HP chart at the bottom...
yikes!!!
http://www.hotrod.com/articles/hrdp-...ngine-buildup/

[pontiacpower]

Oh I forgot to give some extra info about the build,
Anyhow this is my first gig and I plan on doing this right the first time with no catastrophies and worry about too much power so I waited till I got some cash to drop on forged parts because a turbo is not out of the question in 5 years when I finish this thing haha.
So anyways where I'm at now
72 400
Forged butler rotating assy. Crank rods pistons
35 over Ross racing forged pistons
4 bolt splayed main caps
60psi oil pump
Number 62 heads out of 69 gto I beleive (bare castings) might sell to pay for the rest of the short block then go aluminum later on
Stock intake
72 q jet
Empty bank account- working on the cam combo and oil pan so I can get the short block done
I been trying to put a motor together for. While now. Thumping 455 gave me the lowdown on e85s compression and boost benefits so I took it and I would say crawled with it cause that was over a year ago I think.
Car has a mild built t350 turning a peg leg 2.88 rear end
I'd like to put a cheaper overdrive (200r4 maybe) in with a posi. Gears don't matter as long as it below a 3.55 cause I'm more of a cruiser and low end torque will be insane from the Pontiac so I hear so low gears won't matter
I may be crazy for a virgin street build but well I'm kind of slow in the head hopefully not on the street

[fatguyzinc]

hey, if it was easy everybody would have one, right?
persevere. the first time you go sideways for 150 yards
and 3 gears it will TOTALLY be worth it..........

[Thumpin455]

When you can run mid 12s in a 3700lb Firebird with 2.56 gears, a 2000 stall, and a very mild stock port 6X headed 455 with what amounts to a factory 068 cam, yeah the gears aren't crucial. The 455 is going to make more vacuum than other engines of similar size with the same cam. Its all in the ports. High velocity very efficient ports are the reason why Pontiacs make silly torque.

Honestly the cam won't make that much of a difference under 6500 RPM unless you go wild, and you won't be able to spin it tighter than 6500 without some worked aluminum heads. Stay under [email protected] and the 455 won't have power brake issues, It will have traction issues with compression and airflow. For a cruiser, no need to go crazy with the cam. The 268 is kinda small, but makes lots of cylinder pressure, that means lots of grunt, easy to move the car away from stop lights, and a mild idle. With a highway gear like 2.41-3.08 that cam will pull extremely hard to 5500, which means it'd be a nice daily driven sleeper.

I've been eyeing some Lunati and Isky grinds, but you really have to look at the .050 duration, because advertised can be very misleading. LUN-10510507 and the Howards 418081-09. These are both 240 ish cams, not really great with stock ports, definitely not good with a 400, low compression, and stock ports and typical Pontiac like gearing. With [email protected] ported 62s, these cams are about the biggest you would want. They aren't far off from the RA IV. The reason I want one of them is my 12.5:1 400 in the 68 LeMans, its getting a bigger stall, around 2600-3000, its been lightened a lot, and I want it to sound mean along with run hard. It has manual everything so I don't care about vacuum. Its more of a street/strip machine than a cruiser.

I went with the smallest hydraulic roller Comp made in the 70 GTO to make as much bottom end as possible, and get good mileage with it. Lots of cylinder pressure with that cam sand my heads. The focus was on mileage, not on max power. I might change it some time to see what that engine can do. What you want makes a big difference, but due to the nature of the 455, nearly any cam between [email protected] and [email protected] intake duration will work with stock ports. I really like the Summit 2802 in my 400s, its similar to the 744 RA III cam. That one would work well for you too, but it doesn't sound mean at all. Pulls the 2.56 rear gear in the 65 easily with stone stock 6X heads on a 400. I ran 11s with an UltraDyne cam that was similar in size to the 2802 with a high compression 455 in my 79 Formula, so I know they'll run.

So what do you want, the most power you can possible make and the rough idle, low vacuum, etc a big cam comes with? Or do you want something different?

[ratpatrol66]

That is head slapping advice! Great stuff Thumpin455!!!

[pontiacpower]

I like all your posts tod. Very in depth. We're any suspension/chassis mods done to get your bird into the 12s? Or was that all engine tranny rear end stuff

When it comes to a cam I want power off idle and a little bit of a rough idle. Todd was that hydraulic roller cam in the 70 when you showed me the video of it running e85 on jack stands? I really wanted to stay hyd flat tappet cause it's cheaper but I'm about low maintenance and doing things once cause it's tough doing this working full time and going to school but i would use hyd roller if that's the way to go. There's a guy who did a 461 build on YouTube and he went with a Comp Cams custom grind Hydraulic Roller 282/288 @ 0.50 230/236 .510/.520 112 lobe separation and his car sounded pretty good. He didn't show any driving videos though so I don't know how it performed or what power he made. I guess what I really love is the pull I feel when I drive my 6.0 power stroke, that thing puts you in your seat but unfortuneately not throughout the whole power band though so I'd like to have that with the 461.