blackbeauty74

Hello, has any of you ever used the Com Cams Magnum line? I am thinking of using the 270H with 240 deg and .510 lift (hydraulic). I have a 74 454 with stock heads and bottom end with edelbrock perf rpm intake with edelbrock 750 carb. I want something with a nice but not to big loppy idle for my cam swap. Can anyone tell me if this cam would give me what im looking for.

Thanks in advance.

SpyderD

I've used two of the comp cam magnum series. The first engine had a 270, with the second engine with a higher compression ratio I went with the 280. You have the cam specs totally wrong - the 270 has 224 deg (at .050 lift) and a lift of .470 I think. The 270 is about as high as you want to go with a stock engine, although a big block may suite it fine. With the 280 (230 degrees @.050) you need some higher compression and maybe some lower rear gears.

Both give a very nice muscle car lope. The 280 matches my car perfectly with my gears and compression. The RPM range is from 2,000-6,000 RPM.

Comp cams also has some good dual pattern cams that may be a better match for stock heads.

edit - I would think a cam with 240 degrees and .510 is a bit radical for a stock engine, even with a big block. For one thing your stock heads probably don't flow enough to make use of the cam, your valve train won't be able to rev up to the RPM's that the cam makes power at, and you may not have the piston to valve clearance for that lift.

HDIronman

I'm running a 280H in my small block, and I think it fine on the street. Plus I have 1.6 rockers to bring it up to .512 lift, and close to 10.6 C/R. The engine idles great at 800 rpm, with some lope, and has tons of torque. Personally, if I had a big block, I would run a little more cam.

Brettmc

Comp has some really nice cams in the Xtreme Energy line. Check some of them out. I've just installed a 274S but have yet to fire it.

Brett

marky mark

I have a newly rebuilt 1969 'vert with a .060 over 427 bb with stock heads, 4 speed and 3:36 gears. Comp ratio is about 9.3 to 1. Running stock cast iron closed chamber heads (some porting done) with a stock GM aluminum intake (period correct) and Edelbrock RPM Quadrajet which I really like, also Hooker Supercomps 1&7/8" with a true 2&1/2" dual exhaust with Dr. X x-pipe and Dynomax Super Turbo's.

I'm running the 270 H Comp Magnum. On the dyno it did 536 ft lbs trq at 3600 rpm and 456 hp at 5100 rpm (flywheel #'s).Held on until 5700 rpm then drops off a lot due to heads and intake. Very flat torque and horsepower curve.

This was the suggestion of an experienced engine builder and he was spot on for my application. Very torquey with great mid range punch as well. I thought about the 280H and might recommend it since you have a 454. Mine is somewhat mild for some tastes but for what I was after I think it was a good fit and I am happy with it. Only downside is the lope isn't real dramatic at idle. Noticable, yes, choppy no. But that's the compromise you make for decent idle/vacuum and low rpm punch.

Either one would be fine. Also, have a look at the Comp Cams LS-6 hydraulic Nostalgia. That one might be even better for you!

Regards, Mark

hudman

I too am running the Comp 270H Magnum in my recently rebuilt 427. My rebuild is similar to MarkyMarks. I kept the stock steel crank, rods, heads, intake, and Edelbrock replacement Q jet. I did replace the pistons with forged Speed Pros (9.98 CR with these heads) and had the heads redone with new valves, springs, pushrods etc. and added 1.72 Comp roller tipped rockers.

I did not have the engine dyno'd, but I expect it is similars to MarkyMarks.

I like the 270. The RPM range is a little lower than the 280 (starts at 1500 vs 2000), which I like. I too seriously consider the 280, but the engine builder recommended against it. I also called Comp's Cam line and they did not recommend it either. They were worried about the vacuum issues.

Idle is lopey, but not too radical at all. In fact, it could be more from my perspective.

I am happy with the 270, but it really depends on how you are going to drive the car. Mine is only a weekend warrior, so I might do the 280 if I had to do it all over again. You probably cannot go wrong either way.

81VetteFreak

I have ran both , the Magnum series and the Extreme Energy .
My preference has to be the Extreme energy series , much better performing and sounding cam .