Uhm...cam?

[Fbomb]

Well the Camaro made a whole 6hp more than last year with the new heads and cam. That adds up to a whopping 265hp to the wheels. Something's wrong. Heads are Dart Iron Eagles, 200cc runner vol. something like 63cc chambers. Cam is a 254/260 .550/.558 on a 110+4. Personally I think that it's way too much cam for this motor/head combo, seems to be creeping up until ~6500 then it just falls on its face. It's only a 355.

Ideas? I'm thinking less duration and more lift with a bit wider lsa.

[1BADAIR]

4/4 race cam

[1BADAIR]

you sure those duration numbers arent advertsed and not @ .050

[DETROITMUSCLE]

same dyno? that could make a big difference in itself.

[ThreeHonks]

you sure those duration numbers arent advertsed and not @ .050

yeah if they are actual numbers at .050"... then your cam is way to big. Any with those 63cc heads you probably have a very low compression ratio (unless running some crazy domed piston). This is all basically resulting in very little cylinder pressure.

EDIT: just read your project thread and seen that you only have 11:1 compression or so. That is not even close to what you need to run that cam. Something in the 12.5:1 area would be best. Is that a solid roller cam?

[sman]

What camaro? Some specs on the car for those of us who dont know would help...

[Fbomb]

Flat tappet cam, the duration numbers are at 0.05" It's the comp xs290s. My dad phoned comp and had them spec it out for him, turns out they just handed him an off the shelf grind! Motor is a 355 with domed pistons and the stuff listed above. I don't remember how much volume the doming takes up...

Car is a 1967 Camaro with a manual valve body Th350 and 4.65 gear in a 12-bolt (Stuff's a powersuck). Supposedly a 3,000 stall but it feels smaller. I think we need to go to a 4,000 or so.
Same dyno as last year, heck, almost same numbers as last year!

And personally I think that throwing my car on the dyno just to get some numbers is pointless because they read so differently. Are any of them actually accurate?

[DETROITMUSCLE]

the only thing that really is accurate is trap speed to weight, but they will give you a good ballpark figure if they have been calibrated properly and on time.

[ezcruisn71]

There are a lot of other factors that come into play than just the cam and head change.
You need to know the RPM range of the camshaft (were peak power is), so you can tune it for this range.
You also have to have the right size carburetor (CFM is based on max RPM range and CID) and the right size jetting at peak power.
You need to match your intake manifold design to your peak power rpm range (dual plane, single plane).
You did not mention your exhaust system, this is also important.
Your ignition system and timing also needs to be setup correctly (total advance, etc.)
Believe or not 110 octane fuel may actually hurt your performance if you don't need all the octane.
If your dynamic compression (on a naturally aspirated engine) is less than 12.0:1 then you should be able to get by with 100 octane or maybe even less!

[1BADAIR]

Believe or not 110 octane fuel may actually hurt your performance if you don't need all the octane.
If your dynamic compression (on a naturally aspirated engine) is less than 12.0:1 then you should be able to get by with 100 octane or maybe even less!

Static compression
dynamic compression shouldnt be more than 7.5-8.5 depending on heads/chamber design

[ThreeHonks]

which with that cam, he probably has a very low dynamic compression, which is killing him

[Fbomb]

I conclude that this is just WAY too much cam for this little 355. Not enough compression anyway. Thinking of recommending a solid roller setup so we can run some more aggressive lobes.