I have a 71 300 hp BB 402 in my 67 Chevelle, I am currently doing a cam swap to the Eldebrock Performer RPM cam kit. I bought the Eldebrock sure seat valve springs, Eldebrock timing chain and gear set. and Crane chromoly pushrods. It has the 9;1 stock pistons in it and already have the Performer RPM intake with a 750 double pump manual secondary Holley, Proform 50,000 volt HEI, Dynomax headers, and 30 series Flowmasters with 2 1/2" exhaust. It also has the M-21 muncie 4 speed and a 12 bolt posi with 3;31 gears. I guess what I wanna know is this all gonna work well together. Thanks.

The cam is way too big for the CR you have. It has 300/306º advertised and should have around 11:1+ to run at it's best. The engine will likely be very soft in the bottom end with little power until around 3000 rpm. With 9:1 CR you should be in the sub 270º range. A 262 or 268 cam would make for a much better driver. Match your gears better, too.

Personal rant! I wish Edelbrock would dump this cam. I ran one for a couple years (was in the car when I got it). it sounds good but without gears, stall, and compression, it is a real stone. Sorry to say this since you just got it but maybe you can return it for something more appropriate to your needs and the rest of your combo.

Thanks Pat,

You got to him before I did!!

Guys, please don't get us wrong here b/c in a true 11 to 1 CR. motor, the old-style RPM cam will run great! Imho...

pdq67

What Pat said :D
I think you will be happy with everything except that cam.
It's pretty lumpy for a 9.0 engine especially with higher gears.

you'd been better off with the Performer cam.

..as stated the RPM cam is way to big for a low compression 402,or any 402 for that matter.

OK guys thanks for your thoughts. I had a pretty much stock cam in there, it ran OK just trying to pull a little more out of it. I don't race the car, pretty much just street cruiser. I already stuck the cam in and sent the heads to have the valve guides reground for the vavle stem seals so pretty much no turning back now. Ill just have to see if I see any improvement or not.Thanks again.

I'd run about 18-20* base timing,total about 36-38* by 2500 if possible.Maybe even a vacuum secondary carb too.

I'd take the cam out now since the heads are off.

BTW, Edelbrock claims 520HP w/the RPM package. Does this sound likely?

Just as the others have said, I can already tell you what the prob will be....itll be a dog at streetable rpms. Play around with advancing the camshaft some to see if you can liven it up any and get the power started sooner.

The RPM cam will work well with Nitrous or a blower. If your plans are for an NA engine dump it.

OK guys I called Eldebrock's tech line today and they said the same thing all of you guys said. They recomended me calling Comp Cams and Crane because they didn't make anything that they thought would work good with the rest of the package that I have. I called Comp and the cam they recomended I would still have to have the valve guides ground the same as the Eldebrock, but Crane recomended a Cam called the Energizer. It is a single pattern cam with 226 duration @.50 with a 0.533int/0.533exh.lift. Advertised duration is 282 and a lobe seperation of 108. I would not have to have the valves ground to clear the valve stem seals. What do you guys think? If you think it'll work good with what I already have I'll pull the Performer RPM backout and swap to the Crane Energizer. smile.gif

That would be a good cam for you, imho..

It's about as big as I would go in a motor like your combination.

And it will be a "thumper" due to the 108 LCA thing too! Should talk to you nice!! Roll her outta the hole and when she hits about 2500 or so "Hang On"!!

Whoa!!! Just saw the M-21!! Maybe a 272 Energizer would be better?? What do you think guy's, b/c the high first gear in the M-21??

And I'm only talking about Crane's cams now....

B/c an Isky 270 Mega or a CC 270 Magnum may be just about perfect if we change brands unless I'm splitting hairs..

But no bigger then the CC Extreme 274 jobber...

pdq67

Crane rates their advertised stuff at 0.004". So at 0.006" the 282 adv number will be about 4 deg less, or 278.

That cam will perform better tha the RPM
IMHO,no matter what you do,an M21/3.31 combo with a 396 will always feel a little "soft" because of the tranny's high ratios.
A 2.88 1st geared ST10 would be a different story.

I think either cam is still a bit too big, but much better than the RPM. Installing either with 6º advance will help a bunch. Getting them on a 108º LSA will help, too. However, with the gears, both trans and rear, I'd go about 10º smaller, yet.

I don't really want to go any smaller, but at the same time I don't want to rob myself of anything. I do want a good thump and a good throttle response. I may be able to swap my M-21 to a M-20, wouldn't that help a little more since the M-20 has a lower first gear? Also I do have power disc brakes I forgot to tell Crane about that. Do you think that the 108 lobe seperation will still give me the vacume I need?

Did you order that cam already?> You'll want their standard 272H10 grind, not the H08 grind. It will be too lumpy in a 402 IMHO.

Heres a nice Crane for you, but again, a mite big...

http://www.cranecams.com/?show=browseParts&lvl=2&prt=5&Vehicle_Type=Auto&Cylinders=8&Engine_Make=CHEVROLET&Year=1970&Engine_Size=396-454%20C.I.&partNumber=133801&partType=camshaft

The p/n/# 60203 on this page is just TOO perfect...

http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECC/Voodoo.html

Gene, after all the time you've been on this board and you still don't know how to alias a URL?

Here you go. smile.gif :D
link (http://www.cranecams.com/?show=browseParts&lvl=2&prt=5&Vehicle_Type=Auto&Cylinders=8&Engine_Make=CHEVROLET&Year=1970&Engine_Size=396-454%20C.I.&partNumber=133801&partType=camshaft)

I had forgotten Crane still made that one!!

Yes, it is an old-school cam but like, (I think), Gene said, it is a Dandy!!

Boy, I am terrible with names.......

pdq67

So which cam do I choose. The Energizer with the .533/.533 lift and a M-20 tranny or the Powermax with the M-21. Heres the rest of the setup so you want have to go back to the original post.

71 300HP BB 402 with 9.5to1 Comp.
Performer RPM intake
750 double pump Holley with manual secondarys
Proform 50,00 volt HEI
Dynomax ceramic coated headers
30 series Flowmasters with 2 1/2" tailpies
M-21 Muncie 4 spd. (currently)
3:31 12 bolt posi.

I'm leaning toward the .533 Crane Energizer with the M-20 Muncie. Tell me what you think.

I ran that Crane 278 (it was called an Econopower Cam then) in a bone stock 8.5/1 '71 454. M22 car with 3.31 gears. I ran it advanced additional 4 degrees than Crane specs. Had a ton of bottum end in the 454 car, I would recommend using the advance keyway on install with this cam, then double check the install when degreeing, but installed straight up it will yield an ICL of about 112, you will want an ICL of at least 108 to keep the cylinder pressure to respectable levels with 9.5/1 CR.

For comparison, my 408 motor with 9.5/1CR and 279/294 duration Comp roller with 113LSA installed at 108ICL is providing 165PSI cranking pressure.