H304/ 355 build spec thoughts

[shane_3800]

If you can afford it go a set of edelbrock heads you can increase compression an extra point and they out flow ported iron heads out of the box.

 

[Deuce]

10.7:1 is just what I was told it would be around with the cp forged pistons mate.
I do already have an edelbrock single plane at home which I may try and see the difference.
vh commodore, t350 3k stall, 9” with 4.11’s
Want something that’ll go pretty hard but still cruise nice. I think crow cams do a bigger hydraulic, I’ll have a look.

Anywhere around the 10.7 range is good for holden iron heads on aussie premium petrol (around 10.5 with alloys on nz premium petroleum ) from what I have heard.
3k stally = go the single plane, no question.

I think even if you fall short of 350whp, but are not dragging it, you will still be plenty happy with it.

 

[VT5LSS304]

Anywhere around the 10.7 range is good for holden iron heads on aussie premium petrol (around 10.5 with alloys on nz premium petroleum ) from what I have heard.
3k stally = go the single plane, no question.

I think even if you fall short of 350whp, but are not dragging it, you will still be plenty happy with it.

Not a drag car but am hoping to run an 11sec 1/4.
Currently a one tonner for sale with a very similar combo and the same cam and it made 403whp apparently.
I’ll get head work done, port match the single plane and see how we go. Bottom end is already together so I’ll tinker with the top end and see how we go I think.

 

[EYY]

I'm not too familiar with that cam but if you don't want a very big cam flat tappet is fine. Don't buy into all the BS were everyone froths at the jaw and tells you, "you need a roller cam" it's a fallacy. Yes a roller is needed if you're pushing to the limits as you can put more spring pressure on it.

You need to understand the benefits of roller cam before posting this sort of thing. Nothing wrong with flat tappet apart from being inefficient and using much older technology.

Basically, you can have manners, reliability, efficiency and performance with a roller cam. A high performance flat tappet cam with equivalent specs will be more difficult to live with (rougher idle, require shorter gears, higher stall etc).

 

[VT5LSS304]

You need to understand the benefits of roller cam before posting this sort of thing. Nothing wrong with flat tappet apart from being inefficient and using much older technology.

Basically, you can have manners, reliability, efficiency and performance with a roller cam. A high performance flat tappet cam with equivalent specs will be more difficult to live with (rougher idle, require shorter gears, higher stall etc).

I agree roller cams are great mate, but the motors already mostly built (bought it like that) and for what I’m wanting I think it would be a bit of a waste of money to rebuild half the motor now.

 

[shane_3800]

You need to understand the benefits of roller cam before posting this sort of thing. Nothing wrong with flat tappet apart from being inefficient and using much older technology.

Basically, you can have manners, reliability, efficiency and performance with a roller cam. A high performance flat tappet cam with equivalent specs will be more difficult to live with (rougher idle, require shorter gears, higher stall etc).

You're grossly overstating the drawbacks of a flat tappet cam.
I understand why roller cams have their advantages I've worked with both. But to claim flat tappets are garbage and shouldn't be used is ignorant and uneducated.
Both have their pros and cons and both have their places in various different builds.
Yes if you're building an engine where you need very strong valve springs due to high RPM and high valve lifts it's essential to use a roller cam. If you're building a fairly budget stroker a roller is not essential and is a cost that could be used else where.

 

[EYY]

You're grossly overstating the drawbacks of a flat tappet cam.
I understand why roller cams have their advantages I've worked with both. But to claim flat tappets are garbage and shouldn't be used is ignorant and uneducated.
Both have their pros and cons and both have their places in various different builds.
Yes if you're building an engine where you need very strong valve springs due to high RPM and high valve lifts it's essential to use a roller cam. If you're building a fairly budget stroker a roller is not essential and is a cost that could be used else where.

It’s about ramp rates and area under the curve. That’s where you’re confused. It really depends on the application and what the user wants out of the combo. I haven’t overstated anything - I’ve just outlined the facts. I have a very good understanding of the merits for both types of valvetrain setup.

You’re the only one suggesting that anybody said they’re garbage. For a budget build, nothing wrong with flat tappet - but it’s very important to understand their limitations when running them on the street in a performance engine.

High spring pressures combined with aggressive ramp rates and low rpm (lots of idling and cruising) can accelerate cam wear and they can eat lobes prematurely.

At the end of the day, roller cam is king. How often do you see people doing flat tappet cam conversions to their Ecotecs or ls1’s?

 

[shane_3800]

It’s about ramp rates and area under the curve. That’s where you’re confused. It really depends on the application and what the user wants out of the combo. I haven’t overstated anything - I’ve just outlined the facts. I have a very good understanding of the merits for both types of valvetrain setup.

You’re the only one suggesting that anybody said they’re garbage. For a budget build, nothing wrong with flat tappet - but it’s very important to understand their limitations when running them on the street in a performance engine.

High spring pressures combined with aggressive ramp rates and low rpm (lots of idling and cruising) can accelerate cam wear and they can eat lobes prematurely.

At the end of the day, roller cam is king. How often do you see people doing flat tappet cam conversions to their Ecotecs or ls1’s?

The ramp rates aren't nearly as bad as people think.
Due to a flat tappet starting on the edge of the lifter then moving to the centre of the lifter at cam centerline it acts like a larger lobe.
Roller lifters follow the cam profile from the centre of the lifter the entire time.
Flat tappets are limited by this very function as you increase ramp rates the edge of the lifter can start to dig in but this is less of an issue the larger the base circle.
This means flat tappets are ideal for mild engines.
There's no black magic to cam choice.

Also how many roller cams fail in LS engines and ruin the expensive cam.

 

[EYY]

I agree roller cams are great mate, but the motors already mostly built (bought it like that) and for what I’m wanting I think it would be a bit of a waste of money to rebuild half the motor now.

Sounded like you were starting a build from scratch from the first post. If it’s already set up for flat tappet and you’re on a budget, forget the roller cam idea for the minute.

I’ve found that I’ve received the best advice through camshaft manufacturers. Give them a call - most are very happy to talk you through your options based on your engine specs and vehicle setup (trans, stall, weight, diff gears etc.)

There are plenty of decent threads on this site and AV8 with cam recommendations and results etc. Personally I’d look into something around the crane 280 in that case if you’re willing to go through with supporting mods.

Don’t be scared to go solid cam just because they require periodic adjustment. If the heads are well set up, clearances will rarely need to be touched.

 

[VT5LSS304]

Sounded like you were starting a build from scratch from the first post. If it’s already set up for flat tappet and you’re on a budget, forget the roller cam idea for the minute.

I’ve found that I’ve received the best advice through camshaft manufacturers. Give them a call - most are very happy to talk you through your options based on your engine specs and vehicle setup (trans, stall, weight, diff gears etc.)

There are plenty of decent threads on this site and AV8 with cam recommendations and results etc. Personally I’d look into something around the crane 280 in that case if you’re willing to go through with supporting mods.

Don’t be scared to go solid cam just because they require periodic adjustment. If the heads are well set up, clearances will rarely need to be touched.

definitely leaning towards solid. Otherwise I don’t think I’ll ever be quite Happy with it, more power the better!!
Edit*
However I did see on another forum site an extremely similar build with slightly less compression go 450hp @ 6000rpm which I think is sufficient for a cruiser with some poke. Should have lots of usable power for the street.