aaroncorvette

Hey guys

I've got a question for you

I've got a 355 in my '71 'vette and an Edelbrock Performer RPM cam -


ENGINE: CHEVY 283-400 V8
RPM RANGE: 1500-6500

Duration at 0.006" Lift: Intake: 308° Exhaust: 318°
Duration at 0.050" Lift: Intake: 234° Exhaust: 244°
Lift at Cam: Intake: 0.325" Exhaust: 0.340"
Lift at Valve: Intake: 0.488" Exhaust: 0.510"
Timing at 0.050" lift: Open Close
Intake: 10° BTDC 44° ABDC
Exhaust: 59° BBDC 5° ATDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°

Note: Use only stock ratio rocker arms.

CAUTION: Use Edelbrock Performer-Link Timing Chain and Gear Set #7800 or Accu-Drive gear drive #7890. Do not use late model timing chain and gear sets that are designed for emission-controlled engines. These timing sets are machined in a retarded position and are not recommended for this camshaft installation. Edelbrock Timing Sets feature three keyways for specified timing selection. Use "0" position for most applications.

Do not use dual valve springs.Use only recommended Edelbrock Sure Seat. Valve Springs #5703. Use stock ratio rocker arms only.

I do like this cam and it sounds great but i have 10-1 compression and an ali flywheel, the other mods are K/B pistons -6cc, Edelbrock Performer RPM heads ( 70cc), Air gap manifold, roller rockers, lightened and balanced, scat 2 rods, 0.020 deck height, 0.015 Fel-Pro head gaskets gaskets.Tremec 600RR (2.87 1st), 3.55 gears.

The RPM cam has long duration (234/244) and low (ish) lift, this is surely old school? My DRC is relatively low ( I guess due to the loverlap).

So my question is does anyone recommened a cam for me (prefer solid, flat tappet) that perhaps has more lift and less duration? Looking for similar or more performance than i've already got, and does a cam with more lift and less duration improve my DCR?

As i want to use a Solid flat tappet cam i'm having trouble cross referencing the two due to the way they are spec'd



I'm fairly knowledgeable about engines but i need a cam pro here!

Many thanks.

Billysvette

Never mind

MotorHead

I have been on this forum for a long time and never heard anyone rave about how good this cam is. Take that how you want

Billysvette

MotorHead

Sorry , that cam is one of the best cams out there

gkull

These are numbers to compare to other cams. The .050 duration and the valve event numbers. Most all cam specification cards give these numbers.

After driving around with this Edelbrock cam what do you really want to change? I would guess that it's street manners are not very good

Duration at 0.050" Lift: Intake: 234° Exhaust: 244°
Lift at Cam: Intake: 0.325" Exhaust: 0.340"
Lift at Valve: Intake: 0.488" Exhaust: 0.510"
Timing at 0.050" lift: Open Close
Intake: 10° BTDC 44° ABDC
Exhaust: 59° BBDC 5° ATDC
Centerlines: Lobe Separation - 112° Intake Centerline

Billysvette

larrywalk

What's not to like? Your dynamic compression ratio is already 8.1:1 - wouldn't go any higher with pump gas. If you shorten the intake duration, the DCR goes higher.

The lift is reasonable, the static compression ratio is reasonable. If you need more power, get better heads, but what you have is already quite good. Have you considered a 383 or 406?

MotorHead

Alright lets not be silly here, why do you have this cam for sale ? I have been on this forum for 10 years and have never heard anyone praise this cam. The posts I remember are from forum members that have reported this cam is too much for there 350ci, from a many points of view.

Do you think I am going to waste my time making a comment about something I don't know anything about ? Go thru all my posts in 99% of the time I only post from personal experience with a part or setup.

Why would I post anything negative unless I have heard something many times. This cam might work for some applications but every time I heard about this cam it is negative. That is the reason for my post, you reason I believe is to sell a crappy cam that you have sitting around.

If I don't have anything to say to help someone who asks a question I don't say anything, you clearly are upset that you might lose a chance to sell your used cam that you had in 383ci in which might work but for some reason you decided to change it. If it is so good it would work with a S/C no problems in a 383ci

Billysvette

Ok your right.

Jack Wood

Cabin fever, I guess.

aaroncorvette

Hey guys, thanks for posting

1 - i'm not bothered about selling the cam

2 - i'm reasonably happy with the cam, just thought a switch to a more modern cam might give me a bit more bottom end torque AND a bit more or the same top end, Solid cams have faster ramp speeds don't they? so i thought a change to one of those might get the valves opening faster but for a shorter duration to bring the overlap down, or would a roller be the better option, i've got enough things to spend money on at the moment and wasn't looking to change to a roller but if that's what it takes then at least i know.

3 - we don't tend to have any issues with fuels over here, i could run 11-1 in this engine and probably be fine

4 - this is as much a theory question as a real world question, i don't want to leave anything on the table, people either love or hate this cam, so a suggestion of another cam ( and why) would be great

5- i don't mind adjusting the rockers with the solid cam, i used to do it all the time on my MK1 Escorts.

Motorhead i'm glad you chipped in, i've read lots of your posts and searched a lot on this subject, the cam either get 'it's crap' or 'it's great' and no alternatives

For example how would a Comp Cam XS274S compare?
http://www.compcams.com/Company/CC/c...?csid=226&sb=2

I've just been looking at this solid roller
http://www.compperformancegroupstore...Code=K12-770-8
at $914 i may as well sell my heads and get some better one's at 64cc to bump the compression up a bit more, decisions, decisions!

larrywalk

If you're wanting a solid roller, try the Voodoo series:
http://www.lunatipower.com/ProductGr...?id=290&cid=58

You may want the 60131, but I love the 60132 in my 406 '78!

aaroncorvette

Thanks, so how would the 60131 perform compared to the Edelbrock cam?

Edelbrock -
Duration at 0.006" Lift: Intake: 308° Exhaust: 318°
Duration at 0.050" Lift: Intake: 234° Exhaust: 244°
Lift at Cam: Intake: 0.325" Exhaust: 0.340"
Lift at Valve: Intake: 0.488" Exhaust: 0.510"
Timing at 0.050" lift: Open Close
Intake: 10° BTDC 44° ABDC
Exhaust: 59° BBDC 5° ATDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°

MotorHead

One more it looks like my appologies to Billysvette

My appologies, it looks like my brother was having some "fun" with my account. I have not been around much in past month due to work related activity and haven't been posting much. I have told him about the RPM cam and do agree it might be little aggressive for a 350ci I would not be insulting anyone with my replies.

CorvetteForum is my homepage and I am automatically logged in as soon as you open the browser, same with my photobucket account with all my pics.

He knows allot about my Vette and and hot rods in general and has helped me work on it so he knows a few things about it and also knows quite a bit about the way I think about certain things related to cars, motors etc. as we work together quite a bit and has his own toys too.

Now I have to find anymore posts he was having some "fun" with, just disregard any recent posts "I" have made that sound real stupid and please don't say they all do

larrywalk

The solid roller profiles can be much more aggressive than any flat tappet due to the geometry of the roller versus a flat tappet. Compare the advertised duration of any cam with its duration at .050" (lifter rise). Because of the quick action of the roller cams (the Voodoo cams are some of the quickest), it will minimize overlap, but still allow lots of area under the curve. Also, the tighter lobe separation angle will improve mid-range torque (110 vs 112). If you've got the budget to step up to a roller, it's a great way to go!

MotorHead

aaroncorvette, I see you want an opinion on 2 cams, I will do a little research and see if I can help you out

DRIVESHAFT

Voodoo roller => <= Edelbrock cam

Billysvette

Its all good I thought it was strange in how you were reacting tell your brother