SBC cam difference? [Archive] - Team Camaro Tech

: SBC cam difference?


sschevellefan
Apr 22nd, 10, 06:00 PM
I`ve got a GMPP 290hp 350 in my el camino. for those not familiar, rated at 8.5:1 but closer to 8:1, dished pistons, 993 casting heads if I remember correctly and the L82 cam which is the old 350hp 350 cam. It runs decent enough and I`ll fine tune it before making any changes but how better or worse would it run with the Crane 274HO6? I`m actually doing a deal for a summit version of that cam now so it`s coming. Any idea of how it will change the power band? Right now it has a Weiand Stealth, Holley 670cfm Street Avenger, HEI, headers, flows,and a 4spd. Will probably get 3.73`s pretty soon as well. I`m going to dial it in with the L82 cam and see what I can get from it before I change it but I`m curious what you guys think about the power difference.

Steiner
Apr 22nd, 10, 07:19 PM
It will make torque lower in the RPM band and it looks like a better fit for that compression. The LSA will also give it a lumpier sounding idle. You will most likely lose nothing up top. Some 1.6 ratio rockers added at the same time will give you a little more lift.

The L82 specs are:
222/222 @0.050"
0.450"/0.450"
114 LCA

Crane 274HO6 specs are:
218/218 @ 0.050"
0.450"/0.450"
106 LCA

sschevellefan
Apr 22nd, 10, 09:58 PM
It will make torque lower in the RPM band and it looks like a better fit for that compression. The LSA will also give it a lumpier sounding idle. You will most likely lose nothing up top. Some 1.6 ratio rockers added at the same time will give you a little more lift.

The L82 specs are:
222/222 @0.050"
0.450"/0.450"
114 LCA

Crane 274HO6 specs are:
218/218 @ 0.050"
0.450"/0.450"
106 LCA

Yeah I figured the specs fit the engine better, always liked tighter LSA`s though most of my cams have been on a 108. I figure it`s a old school cam but not as lazy as the GM cam. I thought about doing 1.6 rockers but I think it would be pointless with the stock heads. I`m thinking about going to some vortecs or a aftermarket version down the road so maybe do the 1.6`s then. Seems like everyone I`ve read about who used the 274HO6 has had nothing but good to say about it so we`ll see how it does in my set up. Going to be a while before I swap but it`ll happen someday.

ace's68
Apr 22nd, 10, 11:44 PM
There isn't much difference in the two cams, the 274HO is actually a tad smaller, but like steiner said it will make torque lower in the band, and for the low compression, that is what you want.
I'd suggest getting the compression up before a cam change, because you won't notice much difference in the two.

sschevellefan
Apr 23rd, 10, 03:22 AM
There isn't much difference in the two cams, the 274HO is actually a tad smaller, but like steiner said it will make torque lower in the band, and for the low compression, that is what you want.
I'd suggest getting the compression up before a cam change, because you won't notice much difference in the two.

Going by what you posted before editing, the 274 is smaller than what is in there. I never said anything about going bigger. I think the compression is fine for the 274 and it will build better dynamic compression than the 40yr old L82 cam. I think I`ll notice quite a bit of difference between the 2 cams. This isn`t my first cam change, I just usually never use such a mild cam.

67 Plum
Apr 23rd, 10, 11:48 AM
The 274H06 will be a good match.You will notice a difference.The 274 will have a nice lopey idle and rev quicker than the L82 cam.More torque also.

John65nova
Apr 23rd, 10, 03:16 PM
How about an Isky 264 Mega for a compromise 264/264, 214/214, 108 LSA. Seems like that would maintain a bit more vaccum and run a lot better than the OEM L82 cam. No idea why GMPP put that cam in an 8:1 engine.

For such low compression, I think you need even less duration than the 274H06 to keep IVC early enough to pick up some cylinder pressue. JMO though... I think either one would be a big improvement over what's in there now.

ace's68
Apr 23rd, 10, 03:38 PM
Yeah that's why I edited it, read the thread too quickly.
I was just saying, if you are really looking for a noticeable performance gain, going to something with more lift and closer to 230* @.050" would be a hot little 350.

trmnatr
Apr 23rd, 10, 04:43 PM
I`ve got a GMPP 290hp 350 in my el camino. for those not familiar, rated at 8.5:1 but closer to 8:1, dished pistons, 993 casting heads if I remember correctly and the L82 cam which is the old 350hp 350 cam. It runs decent enough and I`ll fine tune it before making any changes but how better or worse would it run with the Crane 274HO6? I`m actually doing a deal for a summit version of that cam now so it`s coming. Any idea of how it will change the power band? Right now it has a Weiand Stealth, Holley 670cfm Street Avenger, HEI, headers, flows,and a 4spd. Will probably get 3.73`s pretty soon as well. I`m going to dial it in with the L82 cam and see what I can get from it before I change it but I`m curious what you guys think about the power difference.

Anthony the 274H06 off the top of my head is 228/228 @.050" .480"/.480" 106 lobe seperation? Is that correct?

Let me know as I have used this cam a few times in 327's and 350's

trmnatr
Apr 23rd, 10, 04:46 PM
Anthony I looked them up, It will have a lot more throttle response and should pull to 5500rpm no problem. Peak about 5,000rpm

sschevellefan
Apr 23rd, 10, 07:17 PM
Yeah that's why I edited it, read the thread too quickly.
I was just saying, if you are really looking for a noticeable performance gain, going to something with more lift and closer to 230* @.050" would be a hot little 350.

If it had more compression and better heads I`d go with the Isky 280 mega. Best hydraulic cam I ever used.

Anthony the 274H06 off the top of my head is 228/228 @.050" .480"/.480" 106 lobe seperation? Is that correct?

Let me know as I have used this cam a few times in 327's and 350's

Butch, it`s 218@.050 and .450 lift 106LSA. I`m thinking down the road to go with some vortecs and 1.6 rockers. Should wake it up good.

sschevellefan
Apr 23rd, 10, 07:17 PM
By the way, I`m getting the Summit version for free. Doing a trade so I`m not out anything. as far as I know it`s just a reboxed Crane cam.

trmnatr
Apr 23rd, 10, 07:18 PM
Go for it with the 1.6's

sschevellefan
Apr 23rd, 10, 07:20 PM
Go for it with the 1.6's


Not with the smogger heads. It would be pointless and not worth the extra money setting everything up.

Steiner
Apr 23rd, 10, 07:30 PM
Yeah, those Vortecs will probably increase your compression at least a point. I think you're right waiting on the rockers....the Vortecs require self aligning ones so you'd wind up buying them twice. Save that cash for the new intake.

trmnatr
Apr 23rd, 10, 07:33 PM
Yeah, those Vortecs will probably increase your compression at least a point. I think you're right waiting on the rockers....the Vortecs require self aligning ones so you'd wind up buying them twice. Save that cash for the new intake.

He could buy shaft rockers from Probe for the same price as rockers and stud girdles (if he were to run girdles)

Steiner
Apr 23rd, 10, 07:47 PM
He could buy shaft rockers from Probe for the same price as rockers and stud girdles (if he were to run girdles)


Agreed. But as is the case with most of us when we start doing an imaginary build, we may be getting carried away on components for an 8:1 0.450 lift flat tappet cammed GM crate.