I'm looking for experianced opinions.
I have a 350 4bolt, poked out to 355. The block has been Aligned, bored, decked and and torque plate honed, off of the crank center line. I have full floating TRW Power Forged flat top pistons. I have Edelbrock alum RPM heads 64cc 202 valves so I should be running pretty close to 9.8:1. I have RPM Air Gap intake. I still need to get steel crank and rods(haven't decided what to get yet) I'm thinking I will use Pro Magnum roller rockers 1.52 ratio. I have free access to an HEI but sure would like to be able to swing a MSD6AL system. Still hav'nt decided on a gear drive or roller chain cam drive. Still hav'nt
decided on a Edelbrock 750 or Holley 750 Vac Secondaries. I have a turbo 400 stock converter and stock 2.73 rearend. I'm planning on going to 3.73 posi and a stall speed of about 2400 to 2800 depending on the cam I go to. This brings me to my real question (alltough comments on the rest are welcome). I have been advised by many fellow enthusiats to avoid edelbrocks RPM cam. I am really impressed with what I hear about Comp Cams and will be going with one of their extreme energy ones. I'm inclined to like the ex284h but not sure if too much or not. What do you folks think? I would like to get above 400 hp as well as 400 lbs.

That cam will get you there, but it is pretty stout and your peak horses will come in around 6500rpm or maybe more. This cam will idle pretty helthily, and might be a little low on power before 2500rpm, but your converter and those 3.73 gears should help that out.

The big thing I would worry about is vacuum from this cam. Do you run power brakes? I know of people on this board who say that they have the XE274 cam and the brakes won't have enough vacuum if you step on them more than once while idling. Of course, a vacuum canister or pump can alleviate this problem too. Good luck!

Thanks for the info. Yes I have power Brakes, and that could be a real concern. Sure would be nice to see some tried out systems on the dyno, but then again everyone has different heads intake and carb combos. Thanks again!!!

In your case I would go with the XE274. The XE284 is too much cam unless you're thinking 3500 stall and 4:11 gears. The vacuum for power brakes won't be adequate with the XE284 either. The webmaster over at prestage.com has a Nova running 12.20's with a 350 similar to yours and the XE274. That gives you an idea of the potential.

Your engine combination is very similar to mine. The specs are on my website, the link is at the bottom of this post.

The XE268 is a really nice cam. The car has a manual transmission so there is a bit more vacuum available. With an XE274 it think the brakes would be marginal. With the XE268 they are fine, but I can tell that the braking power is off from a high-vacuum cam.

A good rule of thumb is if there is a choice between two cams, choose the smaller one.

I can email a soundclip to you if you would like.

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The Red Beast http://www.geocities.com/casanoc

<BLOCKQUOTE>quote:</font><HR>Originally posted by sneakey pete:
Sure would be nice to see some tried out systems on the dyno, but then again everyone has different heads intake and carb combos. Thanks again!!!<HR></BLOCKQUOTE>

Actually, there is a way. I happen to have a program called the desktop dyno, which is a piece of software that calculates torque/horsepower curves using flow numbers for heads, cam numbers, compression, etc. Here is an example of the difference between the XE268, XE274 and XE284.

The short block is as you described, 9.8:1 compression with the RPM heads, I am running these simulations with small tube headers and a free flowing exhaust.

XE 268...
rpm hp tq
2000 150 393
2500 189 398
3000 231 403
3500 276 414
4000 317 417
4500 354 413
5000 378 397
5500 392 374
6000 383 335
6500 362 292

With the 274...
2000 144 378
2500 184 387
3000 225 394
3500 270 405
4000 313 410
4500 353 412
5000 383 402
5500 399 381
6000 400 350
6500 397 321

finally the XE284...
2000 133 349
2500 174 365
3000 212 371
3500 259 388
4000 306 402
4500 348 406
5000 383 403
5500 406 388
6000 413 362
6500 410 331
7000 398 299

According to the flow numbers, the RPM heads flow well, but not as well at higher lift figures. This stifles the potential of the bigger cam. As you can see though, the heads good flow numbers down lower, combined with a shorter cam makes some good torque and respectable horsepower.

Thanks one hole big heap for the info !!!!!