[TAQuest]

Tear down picture below;
https://share.icloud.com/photos/0uv4...r_Township,_MI

[chiphead]

Originally Posted by Formulajones

That Edelbrock cam is a copy of the original GM RAIV camshaft.

What did you tell the tech for him to recommend that??

All I can say is, in a 400 it's going to be choppy so I hope you like some attitude, and I hope your engine has enough compression ratio to support it because no one here could seem to agree on what that might be. If it's below 10:1 as some suggest, that cam is going to act a bit soggy in a 400. If it's above 10:1, prefer 10.5 or better, it's workable, will idle better and make a little more vacuum.

On the plus side at least you have a 4 speed so you don't have to worry about converters.

A bit soggy may be an understatement. Over the years, we've had a few guys come on this site with a RAIV cam in moderate compression 400s. The common complaint is rough idle, poor idle vacuum and lack of power below 2500 RPM. Above 3000 it'll pull hard until it floats the valves or runs out of air.

A snip from Hot Rod:

With a cam that spec’d at 308/320 degrees of duration for the intake/exhaust and 87 degrees of overlap, it was one of the more finicky street motors out there. But that’s what it took for Pontiac to compete against larger competitors. With 10.5 compression, it put out 370 hp at 5,500 rpm and 445 lb-ft of peak torque at 3,900. Only 3.90 or 4.33 gears were available.

https://www.hotrod.com/articles/1970...n-to-the-rule/

The engine itself looks clean. I like the glyptal paint in the valley, I did the same with mine.

[Steve C.]

The Edelbrock cam has a whopping 87 degrees overlap, 35 degrees more than the Voodoo 703 cam.

One source... Increasing overlap increases top-end power and reduces low-speed power and idle quality. The goal to make valve overlap useful is maximizing power output to the RPM band the engine is designed for. Commonly overlap can range from 60° to more than 100° on a race application, a mild street application operating between 25° to 55°, compared to a stock engine of between 15° to 30°. with that is the statement is not knowing the cubic inches involved.

( Issue with those numbers is cubic inches involved, but it serves the point )


There is no downside to lift. If there are no clearance issued involved, more lift is always better. If you want to build a street motor with the most power without a sacrifice of idle and low speed qualities, then lift is the most important factor to maximize, not duration. The best street cams are those that seek to maximize lift while only adding a minimal amount of duration.

Edelbrock cam 0.470" lif
Voodoo cam 0.489" lift


.

[TAQuest]

Originally Posted by Steve C.

Better choice.....

http://www.lunatipower.com/Product.aspx?id=1776&gid=287



And before anyone starts throwing darts at the Voodoo cam's 110 lobe separation seek out Paul Carters very specific information presented on that subject as to why they are much different than other cams, such as the Comp XE flat tappet lobes.

.

Caught the order before it left the warehouse and changed to this cam.
Voodoo Hydraulic Flat Tappet Cam - Pontiac V8 268/276

Product Description
Hydraulic Flat Tappet Cam. High performance street/strip cam for 350 c.i. motors. Excellent cam for 400- 455 c.i. touring type vehicles with 9:1-9:5 compression ratio. Use 2200-2400 RPM stall converter with 3.23-3.42 rear gears. Very noticeable idle quality.
Advertised Duration (Int/Exh): 268/276
Duration @ .050 (Int/Exh): 227/233
Gross Valve Lift (Int/Exh): .489/.504
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1600-5800
Includes: Cams Only

Part Number: 10510703
Previous Part Number: 60903

[pastry_chef]

Originally Posted by Stan Weiss

Steve,
No sure if I missed something, but using your numbers I get

56.48354
------------ = 9.8377 to 1
5.7154

Stan

Pretty much the same, image attached (CC and cu.inches).

[SA74SD]

I've tried following this for over 450 replies. I do recall two things by the OP.
36 degrees total timing and never uses a timing light, times by ear.
A degree wheel and confirmed TDC would put the guesswork on that cam to an end.
I wish you luck and success.

[TAQuest]

Originally Posted by SA74SD

I've tried following this for over 450 replies. I do recall two things by the OP.
36 degrees total timing and never uses a timing light, times by ear.
A degree wheel and confirmed TDC would put the guesswork on that cam to an end.
I wish you luck and success.

A degree wheel while it's in the car? hmmm

I'm going to settle for the piston stop I made earlier and a marked up balancer.

To each his own.

[pastry_chef]

If the cam will be a Voodoo 703 then the intake lobe should very close to .075 lobe lift at TDC when installed, maybe a few thou more.

[Formulajones]

Degree wheel can be used in the car, just a little more tedious and time consuming. I've done several "in car" cam swaps using a degree wheel. Everything you have to remove out of the way to slide the cam out gives you the room needed to use the degree wheel. Just sucks laying over the fenders trying to use it.

[Steve C.]

"Caught the order before it left the warehouse and changed to this cam."

And with the cam you will need to upgrade the valve springs. And yes, I know I already mentioned that.

.

[grivera]

Like others here, I strongly recommend you buy kit and degree the cam. You’re this deep in it and should do it right. And, it can be done in car while not easy.

[TAQuest]

Originally Posted by Steve C.

"Caught the order before it left the warehouse and changed to this cam."

And with the cam you will need to upgrade the valve springs. And yes, I know I already mentioned that.

.

Got a link to the springs? Do you need any measurements to decide which ones to get? Or do you already have all the info now?

[TAQuest]

Originally Posted by grivera

Like others here, I strongly recommend you buy kit and degree the cam. You’re this deep in it and should do it right. And, it can be done in car while not easy.

I have three recommendations here to use my piston stop and mark up the balancer. They say that will work just fine. Thanks for your opinion.

[steve25]

Degree checks can be done far easier and faster in car if you pull the grills out.
Spend the extra bucks and get the big moroso wheel.

[TAQuest]

Originally Posted by steve25

Degree checks can be done far easier and faster in car if you pull the grills out.
Spend the extra bucks and get the big moroso wheel.

You must not read what I write.

[steve25]

I read what you wrote, my reply was more for other people who may have the need to do such.

[TAQuest]

Originally Posted by steve25

I read what you wrote, my reply was more for other people who may have the need to do such.

And that's why we have such a mess here with so much extra posting that is meaningless. I would take out about 1/3 (or more) of the garbage in this thread to make it useful.
From now on just post to me in this thread. When you go on and on arguing a point it's worthless. OK?
Thanks for your help.

[TAQuest]

Here we are deciding on valve springs for using a '703 cam in Edelbrock 60599 heads.
It's a Lunati Cam so let's use information from their website;

Valve Spring Tech
Valve Spring Pocket Clearance
Valve spring pocket clearance is the gap between the inside diameter of the valve spring pocket (or cup, if used) and the outside diameter of the valve spring.
Too much clearance will result in the spring "dancing" around in the head, which "beats up" the spring mounting surface and the spring itself. If this is the case, a spring cup may be used. Additional machining of the spring pocket may be required to accept the spring cup.
Not enough clearance will bind the spring in the pocket, overstressing the bottom coil by limiting its movement and not allowing the spring to "grow". This will cause the bottom coil to wear against the head and/or prematurely fail. Machine the valve pocket using a Spring Seat Cutter if not enough clearance exists.

Valve Spring Retainer Fit
The valve spring retainer should fit the valve spring being used. A slightly snug fit is acceptable, however a fit that is too tight can overstress the top coil, and cause it to fail. A fit that is too loose can lead to spring "dancing."
Valve Spring Installed Height
The installed height of the valve spring is the distance between the valve pocket (or cup, or shims) and the outer edge of the spring retainer (which is the height of the valve spring) when the valve is closed. To check installed height, follow the following procedure:
Install the valve in the guide.
Install the retainer and valve locks.
Install all spring cups and/or valve spring shims (basically, everything except the valve spring).
Hold the valve closed by pulling the retainer up tightly against the valve locks.
Measure the distance between the outside edge of the valve spring retainer and the spring seat. A snap gage or a height micrometer should be used.
Check the distance against what is recommended on the camshaft specification card. An installed height of +/- 0.020" is acceptable.
If the installed height is not within 0.020", either machining of the valve pocket, or removal/installation of valve spring shims is necessary.
Repeat this procedure for the rest of the valves.

Valve Spring Retainer to Valve Seal Clearance
The distance between the innermost step on the valve spring retainer and the valve guide must be 0.090" larger than the maximum valve lift of the camshaft. Measure the distance between the top of the valve seal to the bottom of the valve spring retainer. After adding 0.090" to your measurement, it should still be larger than the maximum valve lift of the camshaft. If not, machining of the valve guide in necessary for adequate clearance.
Valve Spring Coil Clearance
Coil clearance is the distance between the valve spring coils when the valve is it maximum lift (fully open). A minimum of 0.060" must exist between the coils at maximum lift. Coil bind is when the valve spring is compressed fully-to the point that all of the coils are "stacked up" on top of each other. For high RPM applications, .100" is recommended . Coil bind is a catastrophic condition that will result in valve train failure. Disassemble each spring (if multiple springs are employed at each valve). Check all the springs (both inner, and outer springs) If there is not 0.060" - 0.100" minimum of clearance between the coils, the solutions are: the valve retainer, the valve locks, the valve, or the spring must be changed; the spring pocket must be machined. Keep in mind that these modifications will change the valve spring installed height

Valve Spring Retainer to Rocker Arm Clearance
When installing the rocker arms, check to see that the inside of the rocker arms clear the spring retainers. Many rocker arms have a "relief" to accommodate large valve spring retainers.
Valve Spring Run-In
Each set of Lunati valve springs are hand-selected to keep load variations below +/- 10% of the next. However, it is important to "run in" your new valve springs at low RPM using the following procedure:
Start the engine and run the engine between 1500 and 2000 RPM until the engine reaches operating temperature.
Shut off the engine and allow the springs to cool.
After initial run-in, most springs will lose a slight amount of pressure. Re-check and shim up the valve springs if necessary. After the springs are "run in", spring pressure should remain constant until the point of replacement.

There are some great pictures with this tutorial at;
http://lunatipower.com/Tech/Valvetra...pringTech.aspx

[grivera]

Originally Posted by TAQuest

I have three recommendations here to use my piston stop and mark up the balancer. They say that will work just fine. Thanks for your opinion.

Those recommendations are correct but don't substitute degreeing-in a cam. Rather, verifying the TDC mark on the balancer is correct and making a new mark if it isn't, is one of the first steps when degreeing-in a cam. Cams are known to be inaccurate - some more than others, and timing sets are usually off too due to varying machining tolerances, so for best performance, installing "dot to dot" isn't recommended . You won't know where the cam actually is without checking those timing events with a degree wheel.

BTW - don't forget to check/set camshaft end-play when reinstalling cam gear - .003-.007 is spec.

[Cliff R]

"The Edelbrock cam has a whopping 87 degrees overlap, 35 degrees more than the Voodoo 703 cam."

Not really, the SPC-8 cam is still ground by CMC and everyone sells it. It's rating is probably at .002" tappet lift so it's going to show more seat timing and overlap than a Comp or Lunati grind. It's interesting how some companies "juggle" the specs slightly to make it look like their own cam.

Advertised duration will vary some, as will the .050" and LSA.

Crower, for example puts a cam card in with their 60919 cam showing 304/316, .469/.469", 231/240 on a 113 LSA, but on the website it's on a 112LSA. Comp shows the cam at 230/240 on a 114LSA. Some show .470" lift and other .469".

I'll bet anyone reading this a steak dinner that ALL of those cams are the same exact grind.

As for the topic at hand, read post #462's on the RAIV cam in the 400.

Just last weekend I custom tuned a real Pontiac Ram Air carb 7040273 for a recent engine build where the builder used the RAIV cam (from Comp) in a RAIII build with #12 heads.

The car has a 4 speed and 3.55 gears, and just like every single guy that came here before him with a "D" port 400 engine and RAIV cam he's got issues. Poor idle quality, stinky exhaust, "soggy" below 3000rpms, etc.

Even with all that said if you think the RAIV cam doesn't work well in a 400 build take a look at how well the 1968 Firebirds are running in Pure Stock.


https://www.youtube.com/watch?v=XMtZNOtxEec

......Cliff