Camming a 10.3 to 1 350

[tcb3274]

Post your selection of a cam for a aluminum headed 350 with a 180 intake runner and that has 10.3 to 1 compression. Car is a street car with a 4 speed and 4:10 gears. Nice cruiser. Hoping for 430 horse out of a roller set up.

[blykins]

Vacuum brakes?

What car?

What heads?

What intake?

What carb/EFI?

Where do you want the hp rpm peak to be?

[tcb3274]

Yes to vacuum brakes.

Car is a 67 chevelle malibu.

Brodix 180 Iron Killers.

RPM Air Gap.

Carb.

Idle to 6000 to 6200.

[Orr89rocz]

Hyd roller in the 218-224 intake duration at .050 and low mid 500 lift. Usually what i have seen. Can go as high as 230 at .050 and still drive well but pull to 6000-6300 in a head like that

Lt1 350 about 10:1 with a 218/228 hot cam drives very well and makes 350’s whp thru a manual trans. Thats 420-430 hp flywheel easily. I would do a slightly more aggressive lobe than those oem gm performance lobes but they last along time and dont need alot of spring

[blykins]

What size carb?

That's where you want the peak or that's where you want to shift it?

What rocker ratio are you running?

[tcb3274]

650 Holley DP

Shift around that area. Peak around 5800 to 6200.

1.5's

[tcb3274]

Hyd roller in the 218-224 intake duration at .050 and low mid 500 lift. Usually what i have seen. Can go as high as 230 at .050 and still drive well but pull to 6000-6300 in a head like that

Lt1 350 about 10:1 with a 218/228 hot cam drives very well and makes 350’s whp thru a manual trans. Thats 420-430 hp flywheel easily. I would do a slightly more aggressive lobe than those oem gm performance lobes but they last along time and dont need alot of spring

Thanks.

[blykins]

Here's where I would be for a 6200 rpm peak:

289/293 @ .006", 235/239 @ .050", 111 LSA, 105 ICL, .563"/.569" with a 1.5 rocker.

This one will have 69° of overlap and will have enough vacuum to run your power brakes, but it won't be noisy or eat valve springs.

[Scotthatch]

Here's where I would be for a 6200 rpm peak:

289/293 @ .006", 235/239 @ .050", 111 LSA, 105 ICL, .563"/.569" with a 1.5 rocker.

This one will have 69° of overlap and will have enough vacuum to run your power brakes, but it won't be noisy or eat valve springs.

?? Heads are only good for 525 lift without more work

[tcb3274]

Here's where I would be for a 6200 rpm peak:

289/293 @ .006", 235/239 @ .050", 111 LSA, 105 ICL, .563"/.569" with a 1.5 rocker.

This one will have 69° of overlap and will have enough vacuum to run your power brakes, but it won't be noisy or eat valve springs.

?? Heads are only good for 525 lift without more work

You mean the spring that comes in them or your saying anything past 525 lift they need some porting work?

[blykins]

I've got flow numbers here for those heads that show increasing flow up to .600". 243/145 @ .500", 245/178 @ .600".

You will lose .010-.020" to pushrod deflection under rpm and valve spring pressure. Even more if the geometry ain't right.

If you're talking about valve spring issues, then it would depend on which heads he has, but most likely the springs would need to be changed anyway with more camshaft.

[Scotthatch]

Head flow at 500 lift is 243 cfm

430 HP needs 209 cfm so port efficiency is 86%

Installed 4 degrees advanced on a 106

15271672383210.jpg

[groberts101]

Post your selection of a cam for a aluminum headed 350 with a 180 intake runner and that has 10.3 to 1 compression. Car is a street car with a 4 speed and 4:10 gears. Nice cruiser. Hoping for 430 horse out of a roller set up.

IMO, the cam should be chosen to work well with that rear gear. But OTOH.. the car is no featherweight either so I'd still probably lean towards a strong mid-range oriented hydro-roller around 230-236 @.050 assymetrical design with slightly more aggressive lobe(IF.. the springs will allow). I've done a couple sets of IK heads through the years and they're pretty decent.. but if unported?.. I'd allow a slight duration split for the more average exhaust flow which will help extend the power curve a slight bit more past peak if the rest of your exhaust system is up to par. Maybe somewhere's around 4-5° extra exhaust duration will likely help extend power past peak. And lift would likely be somewhere in the .550-.575 range. 109° LSA @ 105 ICL.

If you plan on running a air gap intake, and I'd highly recommend it for this app, you could easily add another 2-4 degrees of @.050 duration to have more cake and eat it too. 750 carb and long tubes no bigger than a 1.75" primary/3" collector. I'd even consider running a merge style collector or collector choke of around 2.25" to help fatten up the mid-range without snuffing any top end power out of the deal.

Why don't you just fill out a custom cam rec form to see what the guys who do this stuff for a living have to say?

[Scotthatch]

Forgot ... you also need more carburetor ... with it being manual say 800 dp

[blykins]

Post your selection of a cam for a aluminum headed 350 with a 180 intake runner and that has 10.3 to 1 compression. Car is a street car with a 4 speed and 4:10 gears. Nice cruiser. Hoping for 430 horse out of a roller set up.

Why don't you just fill out a custom cam rec form to see what the guys who do this stuff for a living have to say?

He essentially did. Some of us send camshafts all over the world.