Isky Mega 280 cam [Archive] - Team Camaro Tech

: Isky Mega 280 cam


sbcBill
Feb 15th, 10, 06:46 PM
Has anyone ever used this cam in a 327/300 horse engine? My car has a 4 speed trans and a 3.73 rear gear. The engine has 2.02 heads W/ 64 cc chambers, a Performer manifold with a Holley 650 dp carb, and HEI ignition. How did your car perform with this camshaft? Was your combo close to mine? The car is street driven W/ occassional strip use. Thanks in advance.
Bill

srode
Feb 15th, 10, 07:03 PM
What pistons?

TJS69
Feb 15th, 10, 08:17 PM
If your car has double hump heads and that cam is hydraulic, that cam is too big. The comp cams 268h is the maximum cam you will want in that combo.

ace's68
Feb 15th, 10, 08:28 PM
I run the 286H magnum from comp as listed above in an aluminum headed .040" 327 and love it.
I don't yet have the gearing to make it shine, but it runs very well, has kept up with a cammed ls1 in a '69, wasn't a full out race but it surprised us.
specs are 238 @.050" 286 advertised, .490" with 1.5's, 110lsa
I would suggest either locked out timing, or get the correct vacuum advance can and tune the distributor well or you will have alot of problems, smaller motors respond to cam changes more drastically, especially one that "big" even though it's really not all that big in comparison to others.
My vacuum is around 6" with a dual plane intake, wouldn't suggest a single plane, it was around 3"-4" with a team G and had to slip the clutch alot to get things going, didn't make anything until 3k and would pull to 7k which I thought was too high.
It pulls well from 2,200-2,500 all the way to 6,500 probably because i'm running out of fuel.

I've heard not to run the comp magnum cams with old school heads...
Don't run either unless you have at least 11:1, mine is 10.8:1 and I feel it needs more compression, runs well on pump gas. My dcr is 7.88 if I remember correctly?

RichSchmidt
Feb 15th, 10, 09:31 PM
I ran that cam for a while in my flat top 350 with unported 461 heads,an old 8004 intake and 600 carb.It ran well,but is much rougher then any comparable size cam.I had a 278 HMV crane in that same engine and while the ISKY might have made a small amount more power,it had a much rougher idle.A popular cam at around the same time was the 280 Magnum Comp.The Isky was roughrer then the 280 Magnum which at the time had 112 degre lobe seperation I think(compared to the Isky's 108).I ran the same exact 280 Isky in a 400 with Dart heads and a Victor JR and it made more we then a lot of the larger cammed 400's I was seeing at the track.

So my opnion is that the 280 Isky cam make really good power but ist as driveable as most other cams of it's size.With a 4speed and the amount of gear you have it should be a fun combo,but it wont pull away rom a stop light at idle.

trmnatr
Feb 15th, 10, 10:47 PM
I ran that cam for a while in my flat top 350 with unported 461 heads,an old 8004 intake and 600 carb.It ran well,but is much rougher then any comparable size cam.I had a 278 HMV crane in that same engine and while the ISKY might have made a small amount more power,it had a much rougher idle.A popular cam at around the same time was the 280 Magnum Comp.The Isky was roughrer then the 280 Magnum which at the time had 112 degre lobe seperation I think(compared to the Isky's 108).I ran the same exact 280 Isky in a 400 with Dart heads and a Victor JR and it made more we then a lot of the larger cammed 400's I was seeing at the track.

So my opnion is that the 280 Isky cam make really good power but ist as driveable as most other cams of it's size.With a 4speed and the amount of gear you have it should be a fun combo,but it wont pull away rom a stop light at idle.

Both the Isky and Comp and Crane 280 are good cams

The 108 lobe center will make the package better all the way around as long as the seat duration is not crazy for the application.

I would run 10:1 and run the Isky 280, Have fun :yes:

docwilcar
Feb 16th, 10, 08:07 AM
Too much cam for your combo and your low speed manners will not be fun. I would look at the Isky 264 Mega cam with 214 dur. .450 lift 108 lsa, Comp. 268HE, or if you want a big lope at idle then the old Crane 274H06, 218 duration, .450 lift, 106 lsa will give you lots of low and mid range power. competitionproducts.com sell the Elgin copy of the 274 cam under part #E1785PM for $100 including lifters. Nice street cam.

sbcBill
Feb 16th, 10, 11:39 AM
The shortblock is stock with the original GM 4 valve relief cast flat top pistons. One thing I do not want is a cam that will make the car impossible to drive. In the past I have successfully used the old GM # 151 in a similar engine. The engine ran good, but I was thinking of a cam a step or two up from the L-79. I already have the 350 horse cam and wonder if I should use it, what do all of you think? I do not yet have the 280 cam.
Bill

TJS69
Feb 16th, 10, 01:13 PM
I would use that L79 cam. It probably will perform better then the 280 in THAT engine. The GM engineer's put the largest cams they could into those engines running those heads. If you want solid then use the 30-30 or the off-road cam, and boost up your compression ! It is true that cam technology has improved in the last 40 years, but so has head technology. It is not good to stick a new modern designed cam into an engine with the old double hump heads. It is like installing Windows 7 on an old P3 computer. It might work, but not very well. The intake ports are just too small on those old heads. If you spend a lot of money or time on those heads, they MIGHT get the job done. The port velocity created by these new cam's is way too much for those small ports !

docwilcar
Feb 16th, 10, 03:30 PM
The 114 lsa of the 350 cam makes the intake close 41*ABDC compared to the 274H06 cam at 31* ABDC, not the best for building cylinder pressure. The comp 274H06 will give you better low and midrange power and rev. to 6200 with good springs. If you need to run the 350 cam then at least advance it 4* when you install it. Even the Comp 268, and264 Mega cams will out perform the 350 cam.

JohnZ
Feb 16th, 10, 05:10 PM
The 114 lsa of the 350 cam makes the intake close 41*ABDC compared to the 274H06 cam at 31* ABDC, not the best for building cylinder pressure.

True, but that late-closing intake event is what makes the "151" cam work at 11:1 compression on pump premium without detonation. :)

docwilcar
Feb 17th, 10, 04:42 PM
Good point, I guess I was assuming his 327 c.r. was 10 or less. At 11 c.r. the short duration cams would be a big problem as you suggest. I saw an old Hot Rod article on a 350 motor at 11.3 c.r. using a Crane energizer 222-222-.467 lift 112 lsa and it made 377 hp at 5500 rpm using 492 64 cc heads. Not sure how that would translate to a 327 but the engine builder was pretty impressed with that cam.

sschevellefan
Feb 19th, 10, 12:45 AM
My first 327 was a used one from a 67 camaro with 520 casting power pac heads. I dropped the 280 mega in there using my pg with a vega converter and 3.08 gears. That thing had tons of power. Ran mid 15`s with a hole in the piston lol. with a better tranny and better gears and heads I probably would have been happy with that set up for a long time. I know a guy who had a 67 camaro with a 11:1 327 with the 280 mega and ported 461 heads that ran 11.80`s. Not that same combo as above but thought I`d mention it for referance

trmnatr
Feb 19th, 10, 01:08 AM
My first 327 was a used one from a 67 camaro with 520 casting power pac heads. I dropped the 280 mega in there using my pg with a vega converter and 3.08 gears. That thing had tons of power. Ran mid 15`s with a hole in the piston lol. with a better tranny and better gears and heads I probably would have been happy with that set up for a long time. I know a guy who had a 67 camaro with a 11:1 327 with the 280 mega and ported 461 heads that ran 11.80`s. Not that same combo as above but thought I`d mention it for referance

Our user names look funny here lol

sschevellefan
Feb 19th, 10, 01:10 AM
yeah. I don`t post here much but there are alot more sbc guys here than on the chevelle page. alot of them are 327`s too.

sbcBill
Feb 19th, 10, 02:49 PM
The factory compression is rated at 10 to 1. My heads are the old double humps from a 66 Vette. The heads have were in my basement since the 1970's, they are real nice too. The only valve job ever was the one I did, deck surface never cut either. The block is from a 65 Corvette. This is a very, very, low mileage engine. It had virtually no wear anywhere when I took it apart. I put a kit in the engine simply to freshen it up. This is an engine I cannot wait to see run with a more performance oriented camshaft. Thank you all for your very valued input.
Bill

sbcBill
Feb 19th, 10, 02:54 PM
One last thing, what about using Rhoads lifters?

sschevellefan
Feb 19th, 10, 03:29 PM
The factory compression is rated at 10 to 1. My heads are the old double humps from a 66 Vette. The heads have were in my basement since the 1970's, they are real nice too. The only valve job ever was the one I did, deck surface never cut either. The block is from a 65 Corvette. This is a very, very, low mileage engine. It had virtually no wear anywhere when I took it apart. I put a kit in the engine simply to freshen it up. This is an engine I cannot wait to see run with a more performance oriented camshaft. Thank you all for your very valued input.
Bill

Bill, I hope you used a steel shim head gasket otherwise your looking at closer to 9-9.25:1 compression with a 4 valve flat top piston. I know GM rated them at 10.25 but ifyou do the math they don`t come close. Thats not to say it won`t run good. My buddy had a similar 327 with a 305 magnum cam and it ran low 13`s. The 280 mega should run better in my opinion. I don`t know about the rhoads lifters, never used them and haven`t really heard anything good about them. I would use iskys lifters to match the cam. I never had a issue running the Isky lifters.

docwilcar
Feb 19th, 10, 04:36 PM
Rhoads lifter work well but most people use them because they over cammed their engines and do not want to go to the hassle of changing cams. I have used them on 2 engines just because I did not want to buy a smaller cam. They do work to calm down a lopey idle and they are a quality product. They will clatter a bit at idle and sound pretty much like a solid lifter cam. You should not buy a big cam with the idea of using Rhoads lifters in my opinion. Select the correct cam for your c.r. and combo. I still think the Isky 280 Mega cam would be too much cam for your 327 if you are at or below 10.0 c.r. but you have the benefit of a 4 speed and 3.73 gears on your side. Your 350 hp cam may be fine if you want to save money. Isky has the 270 Mega cam with 221-221 .460 lift 108 lsa that would work pretty well in your combo if you are under 10.5 c.r.

sschevellefan
Feb 19th, 10, 04:43 PM
the 270 mega would be a good cam too. My buddy has a simlar 327 with a old 280 isky that is 224@.050 and .465 lift. The use to make a regular 280 and a 280 mega. I guess they dropped the standard 280 cuz the 270 mega is pretty close. Anyway, with a 4spd and 3.73`s in a 65 chevelle he had a really fun street car. He recently swapped to a 6spd and took it to the track and ran low 15`s spinning throuhg 1st, 2nd and 3rd.

I`ve never been a big fan of the 151 cam but my current toy has a gm 290hp 350 crate engine with the L82 cam which is pretty similar. with a 4spd it actually runs pretty good. I can see me leaving it alone for a little while. I just don`t like the wide LSA`s that GM`s cams have. Isky has always been my favorite when it comes to a hydraulic cam.

sbcBill
Feb 19th, 10, 05:24 PM
I have not done the math to determine the actual cr. The head gaskets are the stock GM stamped tin aluminum painted style and not the thicker compostion gasket. I mentioned the Rhoads lifters because my cousin suggested using them to calm things down. I do not mind the noise, infact, I like the music of a solid lift cam. I agree, do not overcam, correctly build the whole combination. This is the hard part, matching all the pieces to get a good running engine with a minimum of changes.
Bill

sschevellefan
Feb 19th, 10, 06:01 PM
In my opinion a 280 mega is hardly over cammed for your engine. You`ll be happy with it. i never saw a engine with a 280 mega that didn`t run good. With the 4spd you can use a little more cam so I would run it.

racemaniac
Feb 20th, 10, 08:20 AM
Rhoads Lifters work very well and I use them in nearly every engine I build. I would suggest their newest generation of lifter which is the V-Max. The nice thing about it is that you can adjust the bleed down rate to match the cam profile and get up to 5 inches of additional vacuum on the more agressive cams.

JohnZ
Feb 20th, 10, 06:47 PM
The Viper V-10 has used Rhoads lifters since 1996; stabilizes the idle and gets it by the part-throttle and city portions of the EPA emissions certification test. :)