ronarndt

I am trying to decide which cam to put in the NOM 454 in my 68 convert. Engine is a 4 bolt main with oval port heads, long tube headers, 850 cfm carb, Edelbrock dual plane intake, flat top pistons and stock distributor. 4 speed trans. I'm trying to decide between the Comp cams Magnum 280H and Comp Cams Extreme Energy XE274H. Does anyone have either of these cams in their car? Note that I plan later to change to better heads, but will do a cam upgrade and aluminum rocker arm replacement now. I'm looking for a strong street machine that maintains some level of drivability in traffic. Advice is appreciated.

cv67

If those 2 were the only choice Id skip the XE

Know you didnt ask but always felt the Iskys ran harder and never had one go flat. Its been awhile though-

TimAT

Send a request to someone like Chris Straub, ask for a recommendation.

wilcar

Isky 280 Mega hyd cam- 232-232@ 050 .535 lift on a 108 lsa is a good old school cam that might work fine too! Currently running an Isky solid cam in my carbed C 4 and one in my 455 65 Gto with no problems.

blue427

I put a 280H magnum (comp cam) in my 427 and I'm very happy with it.It runs strong and sounds good.I have 10 1/2 comp. flat top pistons and oval port heads(larger valves and 3 angle valves.If you decide to go with this cam p.m. me as I have a new one in the box.When I had this engine built I told the builder to check the cam(same 280H magnum) and if it was perfect put it back in and give me back the new one,that's how I wound up with a new one.I use there roller tip rockers,lifters'push rods and posi locks.I also have Hooker super comp headers with side pipes.

ronarndt

"never had one go flat" I have no real brand preference, except that I had two NAPA stock cams for a 454 truck engine lose a lobe (twice on two cams) on a 454 I built a few years ago. Poor quality control on the Parkerization of the cam. I used Comp Cam products on two other engines and they were fine, but they were mild profiles for low end torque. Isky is of course a quality product, but I have not used them- that's why I am asking advice. Would be nice to have the time to swap out several different cams on my engine to see which works best.

ajrothm

There is WAY better cam choices out there then those two you posted...With stock heads, try to get something with a 8-10* split on the exhaust side.

But out of those two, I would go with the XE274....Its probably a decent all around cam.

Also look at the lunati Voodoo series.

Atleast get something designed within the last decade or so...

ronarndt

I was also looking at Lunati. Problem is every manufacturer will claim that their cam is the best bang for the buck. I did find an article in Chevy Supersports where they put a crate engine 454 similar to mine on a dyno and tested three Comp Cams XE 268, 274 and 284 duration on the same engine. HP ran 475, 505 and 535, with the 274 being the best balance between HP and drivability, Wish I could find similar tests on other cams and manufacturers.

Jebbysan

The 280 Magnum is a great old school cam with soft ramps....great for street....they sound very good too.
The 280 Mega Isky is excellent as well.......
The modern grinds may eek out more power but have quicker ramps that may compromise break in.......

Make sure to remove inner spring during break in.

Good luck,

Jebby

cv67

Not worth 10 lb ft lbs if one wants to speed things up and run up risk of failure just put a roller cam in it. Bought the fast ramp soup yrs ago all failed fast.

crf311

I would convert to a roller cam. IMHO

ronarndt

I'd like to do the roller cam, but there is a $1K difference in the cost. I just retired and went from being in that evil upper 1% income bracket to just regular folks, so I have to watch my pennies spent.

bluedawg

X's two...

bluedawg

Come on old man...we know that you have a bank load, so much so you don't need to eat cat food....lol...hahahaha...

427Hotrod

Not sure which oval ports you have....but with typical flat tops, a .040"+ head gasket and maybe a valve job that sinks the valves...there's a good chance you barely have 8.0 compression..if lucky. Many replacement pistons are "short" and drop them an extra .020"-.040".

Definitely going to need to think through the cam to build a little cylinder pressure in that thing to make it exciting. I don't think those two are your best bets.

JIM

cv67

bluedawg

ronarndt

"eat cat food" If you put tabasco on it, it's not bad.

ronarndt

You are right about the compression ratio. The NOM 454 is from a one ton truck, so I am guessing it is 8.5 CR. When the weather gets too nasty to drive it this fall, I may just bite the bullet and do it right and put aluminum Brodix heads on it, along with a different cam.

427Hotrod

8.5 would probably be on the high side. Do you know which heads you have? Casting number? Sounds like they are peanut port heads. Those can do pretty well with some serious porting...but not sure it makes sense if you can't do it yourself.

You've got a good block...hopefully a steel crank too...so it wouldn't be terrible to swap pistons and get some compression, decent heads....and a cam and be looking at 550-575+ HP with a flat tappet easily.

JIM

427Hotrod

Or you can take a look at this 640HP 496 with 9.7 compression, iron oval ports and L72 intake:

http://www.chevelles.com/forums/13-p...6-496-l78.html


JIM