Stock 304, Guide to choosing a camshaft

[exec24]

if anyone's interested

Holden Commodore VB VC VH VK V8 EFI Auto V8 5L 304 Greenfoam Tune Delco 808 | eBay

 

[Brisbarnz]

I used the 5000i chip, motor now idles and sounds more crisp with better response. Can now hear a slight lope in exh note. Very happy. Revs cleanly. Now rego n road test

 

[434chev]

When you guy talk cams. . There are some points to consider .
The closing of the inlet at 50 this will be the dynamic compression ratio
The opening of the ext will be the rev range and reduce pumping losses
The over lap will help with scavenge but will need less back pressure and head design
High lifts will slow the air speed and raise the power band to a higher point of choke
Area on the lobe can be achieved in many ways . Rocker ratio , lobe intensity small base circle , and large
Wave pulses inlet and ext
Understanding the above points and knowing the maths is why some cams work better then others .

 

[Cameron Tomlonson]

So ive done some reading. But wood like some confirmation.
Im rebuilding my daily vn berlina wags.
It has hsv headers hi flow cat and 2.5 zorst with 3.9 gears and std stall.
Im chasing beat fuel economy with pwr increase not critical but a bonus.
Was going to run 9.5 comp and blueprinted. Slight headwork.
CAM SIZE THO. 4502 crow or some trickey wade cam from 1st post or does somebody have a secret grind.
Also any accompanying valce train modz.
Cheers

 

[EYY]

That cam will have the inlet valve open for a longer duration that the exhaust valve. IMO, I'd go for a symmetrical or a forward split grind, so that it won't struggle to breathe in the upper rpm range. Even with a crane 268 (206/[email protected]), the power curve changes dramatically - with this cam you lose a little below 2000rpm but gain an incredible amount over 2500rpm, although the power tapers off after 5200 or so. I've recently (just last week) driven a stock cammed and a 268 cammed 304 back to back. The stock one didn't really make much power over 3800rpm, and just seemed to make more noise.

For a good balance between power and economy I'd be looking at the crane 276. Using those 3.9 gears will allow you to make the most of the mid to upper rpm gain, and if tuned well should be good on fuel. Still, a 2500rpm converter would be a worthy investment.

Don't need to do much to the heads. Just blend the bowls and take off any casting dags. You won't need roller rockers, but for longevity and reliability they aren't a bad idea. Good valve springs are a MUST and will ensure that your rpm isn't limited by valve bounce and that the lifters don't hammer the cam etc.

A full twin exhaust (including cats) is worth at least 20hp and a considerable improvement in throttle response according to crow cams (I spoke to them over the phone) and the local exhaust shop. I haven't fitted a twin exhaust to mine yet so can't give first hand experience on this, but I will be able to shortly.

Clive from Clive cam's has the documentation for all old wade grinds, and can supply that cam from the first page, but when I contacted him I was quoted ~$400 plus lifters and ended up going with crane instead. Don't rule out camtech cams - they have some more modern grinds which seem more appealing. It may be worth giving them a call.

IMO, anything over a 276 is too big for a daily driver with stock stall. At the absolute most, I'd consider something at around 222/[email protected]. But the inlet manifold will be starting to become a decent restriction in the upper rpm if you've got a decent combo with that sort of cam.

 

[Cameron Tomlonson]

That cam will have the inlet valve open for a longer duration that the exhaust valve. IMO, I'd go for a symmetrical or a forward split grind, so that it won't struggle to breathe in the upper rpm range. Even with a crane 268 (206/[email protected]), the power curve changes dramatically - with this cam you lose a little below 2000rpm but gain an incredible amount over 2500rpm, although the power tapers off after 5200 or so. I've recently (just last week) driven a stock cammed and a 268 cammed 304 back to back. The stock one didn't really make much power over 3800rpm, and just seemed to make more noise.

For a good balance between power and economy I'd be looking at the crane 276. Using those 3.9 gears will allow you to make the most of the mid to upper rpm gain, and if tuned well should be good on fuel. Still, a 2500rpm converter would be a worthy investment.

Don't need to do much to the heads. Just blend the bowls and take off any casting dags. You won't need roller rockers, but for longevity and reliability they aren't a bad idea. Good valve springs are a MUST and will ensure that your rpm isn't limited by valve bounce and that the lifters don't hammer the cam etc.

A full twin exhaust (including cats) is worth at least 20hp and a considerable improvement in throttle response according to crow cams (I spoke to them over the phone) and the local exhaust shop. I haven't fitted a twin exhaust to mine yet so can't give first hand experience on this, but I will be able to shortly.

Clive from Clive cam's has the documentation for all old wade grinds, and can supply that cam from the first page, but when I contacted him I was quoted ~$400 plus lifters and ended up going with crane instead. Don't rule out camtech cams - they have some more modern grinds which seem more appealing. It may be worth giving them a call.

IMO, anything over a 276 is too big for a daily driver with stock stall. At the absolute most, I'd consider something at around 222/[email protected]. But the inlet manifold will be starting to become a decent restriction in the upper rpm if you've got a decent combo with that sort of cam.

Important info i forgot to mention is car will barely see above 4500to5000rpm and never see a drag strip. I also am not interested in peak hp but best hp in the 1800 to 4500to5000rpm range. What u said about heads is exactly what i had planned.
Camtech is where i was looking. Wood like to g complete retro rolla setup but budget isnt there yet and it needs to be built very soon.
Labour is not the issue money wise its parts as i have a family friend who will b building it cheep cheep.

 

[EYY]

If you're not going to rev it, there's no point putting a cam in with all the extra work.

For a small daily driver style cam the 268 or crow 4001 is perfect.

 

[Immortality]

The problem is those cams are such old lazy grinds and you should be able to get something much better these days.

I suggest you have a look at what Kelford Cams in NZ has to offer off the shelf. https://www.kelfordcams.com/global/camshafts/holden/efi-304-v8

To make a simple comparison of what I suggest,

The Crane 268 is,

206°/206° @ .050" and 268°/268° advertised (.006") duration on 112lsa with .448" valve lift

The equivalent Kelfords grind is the 170A

206°/206° @ 0.050 but only 256°/256° advertised duration on 114lsa with .440" valve lift

The Kelfords grind with exactly same .050" duration will perform better right through the rpm range (with the same compression) because of the shorter advertised duration (which means the valve seats earlier) and therefore bleeds off less cylinder pressure which means better cylinder pressure and a better bang for your buck.

IMHO using something like an (old) Crane or Crow off the shelf grinds you are leaving power/torque on the table especially if you are using stock or near stock compression ratios!

 

[Cameron Tomlonson]

Ok thanks. Will send kefords an email cheerd

 

[Cameron Tomlonson]

Just outta curiosity.
What is biggest cam size u can go without machining heads to fit bigger valve springs ect. Just a straight bolt up kit.