Anyone using CSC 274/274-108 cam?

[2v XLE]

Looking at upgrading my 2v cam to this 224deg cam with 108 l\c

http://www.classicinlines.com/proddetai ... 274-HSP-08

Currently running a crowcam IN 32/68 EX 72/28 214@0.050 110 l/c

Carb will be a holley 465, 5 speed manual and 3.5 lsd all in a 1100kg cortina.

Need to keep max power to 5000-5100rpm - don't want to go any higher as I'm only running stock rocker gear, plus i don't drive there anyway.

Just want a bit more then what the 214deg cam is giving me.

I'm also open to suggestions.

cheers

 

[MPGmustang]

to keep it in a 5000 to 5100 you'd advance it 4*, or if you want to be more aggressive you can try 6*. I'm running the 264/274 110*
the 108 lets you rev faster which I guess your going for. but the 274 - 108 will have a very rough idle and low vacuum.

 

[2v XLE]

yeah the vacuum worries me a little.

how does your cam perform? revs? power? what sort of build do you have?

 

[xctasy]

Aussie metric =1100 kilograms

REST OF US= 2425 POUNDS

25% more capacity means that a 274/274 cam might be a little too mild, and observations from our 200 cubic inch brothers don't relate to the 250 due to some major dynamic issues. The rod ratio, bore to stroke ratio, the 50 extra cubes making the 250 an engine with 25% more capacity, and your light weight and gearing just beg for some more intensity in camshaft duration at lash, and at 50 thou.

I'd look for something wilder, and go for the next cam up. CSC-280-HSP-08
280/280-108* Hydraulic Cam.

According to the Aussie development engineers who did 250 2V modifications back in the late 60's, As you 'cam up' a 250, the peak power rpm stays low, so you won't end up ever having to rev a 250 lots above 5100 for power with even a cam with 230 degrees lift at 50 thou.

A 465 4-bbl carb will mask most of the lope of a wilder 274/274 cam on tight lca's. If your worried about idle quality, you'll not see the benefit of the cam. Remember, Ford made emissions legal E303 cams with 284 degrees and 220 50 thou figures for 5 liter Mustangs, and in our sixes, starting with 250 cubes removes the chop at idle you'd normally see in a 200.

Even the venerable little Aussie 202 Holdens with 12 port heads sit at only 5100 rpm with a 284 duration at lash or 224 50 thou, and give over 220 hp with just a 4412 500 cfm 2-bbl. Stock XU1 GTR's and E49 Chargers in modifed sedan races ran lots of duration (302-312 deg) with 5300 rpm power peaks, so your safe going much wilder than the 274/274 108.

 

[2v XLE]

Aussie metric =1100 kilograms

REST OF US= 2425 POUNDS

lol

According to the Aussie development engineers who did 250 2V modifications back in the late 60's, As you 'cam up' a 250, the peak power rpm stays low, so you won't end up ever having to rev a 250 lots above 5100 for power with even a cam with 230 degrees lift at 50 thou.

Is this mainly due to the fact that the head can't get enough airflow much above 5000rpm, restricting power? I'm a bit of a cam noob, but if thats the case, why do manufacturers try and give a 'rev range' or 'powerband' for a camshaft for a specific engine?

 

[xctasy]

No, its due to the rod ratio being 1.51:1, not 1.8:1. That lowers the rev range when the engine is cammed up. Cam makers run anaylsis programs to validate their cams, but they have to set an envelope of possible rev ranges.

Air flow is definatley not a problem with the 2V head, or even the x-flow head. Article is from Street Machine's Hot Sixes series from 1990.

 

[2v XLE]

Thanks for that, makes for some interesting reading.

Being a streeter, I'd still want something that will start pulling from 2000rpm. My low gearing should be adequate to get it moving until it starts camming from 2000rpm.

Could the compromise of going to a bigger cam like the CSC-280-HSP-08 be that all my power is going to be at the top end?

 

[xctasy]

Not on a Falcon six. Lets do some basic comparisons. The rev range on similar ohv sixes like Holden 202's and 265 Hemis is that even with 306 to 312 degrees, power was never above 5300 rpm. The engines could rev to 6500 all day, but still had useable peak torque and power at 3000 and 5300 rpm respectively. Some special cams made certain XU1'S unstreatble, but only when duration went over 308 degrees. Each were short stroke engines, with good rod ratios. 1.62:1 for the Holden 3.3, and 1.56:1 for the 265

A 280 will end up mild, not wild, on a 250. Very similar to an E38 265 Charger cam. Carbs and periferals alter the tractability, but a Falcon 250 is a 1.51:1 rod ratio, long stroke engine.

If your skeptical still, how about Dick Johnstons 1987 SVO 4.1. 280 degree cam, stock EFI, headers, and 2.77:1 gears with T5 in the car Stahl drove for the Wheels article , but 2-bbl version with this cam gave 196 hp, and was still tractable too.

Or the Wade 169 in a 1982-1985 Group 3 308 Holdens, yielding just 252 hp, but a great emissions legal 30/70 /280 degree cam with power to 5800 rpm, but peak power at 5000 to 5500 rpm. A 1.84:1 rod ratio engine with short stroke.

I used to have Feb 1987 magazine article on the SVO Falcon on line but its dropped off my HP Photo account. All of it adds up to 280 degree cams working just fine with 250mcube engines of any type.