[TAQuest]

Originally Posted by Stan Weiss

If that is the case (and I don't, I believe the cam was installed wrong) then why was the engine done at 3200 RPM?

Worth saying again



Stan

Why? I don't know. If it was cam related then we will be fixing that. If it was not then we will fix that too. Cam first. One rock out of the field at a time.

[HO Kenny]

My 68 Firebird ran almost exactly like you described at first. After a long process of troubleshooting something was loose in one of the mufflers. It would block off the exhaust at about 3000 rpm under load. With no load, The exhaust gave no indication it was plugged at all. I disconnected it at the headers to test it. What a difference!
My friends car acted almost the same and it was the coil.

[Stan Weiss]

Originally Posted by TAQuest

Why? I don't know. If it was cam related then we will be fixing that. If it was not then we will fix that too. Cam first. One rock out of the field at a time.

Just saying what I would do if it was my field and my rocks. lol

But it is your field and your rocks. Good Luck

Stan

[STEELCITYFIREBIRD]

Yes, be gentile when rolling it up from both sides. Taper the tip of the bolt too.
Find what you have before spending time on amaking a new pointer.

[TAQuest]

Originally Posted by Stan Weiss

Just saying what I would do if it was my field and my rocks. lol

But it is your field and your rocks. Good Luck

Stan

Yup.
Maybe a $17 timing set from a warehouse that would close soon after they sold it was funky and the dots were wrong? Or the cam was ground wrong.? Hang your hat on that rather than thinking that all the mechanics working on the engine were wrong.

[HO Kenny]

We’re cheering you on even if our opinions are proven wrong. I would suggest a timing light once you know that the ignition timing marks are correct.
If it runs better timed way off it may point to the problem.

[chiphead]

It'll run after you change the cam, because that'll force you to pull and retime the distributor and re-tune the carb.

[STEELCITYFIREBIRD]

Busy here today!

[TAQuest]

I will be going with the Edelbrock 7157 cam.

[grivera]

Is that a RAIV cam? seems like lots of cam for that build

https://www.summitracing.com/parts/e...SAAEgJNbPD_BwE


Basic Operating RPM Range: 1,500-6,500
Intake Duration at 050 inch Lift: 231
Exhaust Duration at 050 inch Lift: 240
Duration at 050 inch Lift: 231 int./240 exh.
Advertised Intake Duration: 308
Advertised Exhaust Duration: 320
Advertised Duration: 308 int./320 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.470 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.470 in.
Valve Lift with Factory Rocker Arm Ratio: 0.470 int./0.470 exh.
Lobe Separation (degrees): 113

[TAQuest]

It's what Edelbrock tech recommends with my set up.

[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.

.

[TAQuest]

The Edelbrock Tech dude was real and credible.

This isn't a cam debate anymore.

[grivera]

I hope it works out well for you

[Steve C.]

The Edelbrock guy sells his cams. Like the Comp guy sitting in his cubicle and regurgitates his 995 valve spring for almost everything.

With low compression which will be better a 113 lobe separation or a 110 knowing a wider LSA number according to Comps website will decrease effective compression.

Similar situation with the advertised duration, 308 degrees vs 268 degrees.

And let's not forget how a engine thrives on valve lift, note that amount of difference. Again, especially with heads that flow well above 0.600" lift !

Onward thru the fog.


.

[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.

[TAQuest]

Bottom Line; Edelbrock guy wants it to run so the customer keeps buying parts. These heads have been out a long time now and they know what works.

At least I know they are compatible. Everything in the whole package is compatible. It's nice out and we just want it to run.

[grivera]

Originally Posted by TAQuest

Bottom Line; Edelbrock guy wants it to run so the customer keeps buying parts. These heads have been out a long time now and they know what works.

At least I know they are compatible. Everything in the whole package is compatible. It's nice out and we just want it to run.

Looking forward to your results and genuinely pulling for you. I'm sure you know the tech guy is simply looking at a computer and the cam wasn't designed around the heads, rather a RA IV copy. The folks on this site are a wealth of knowledge and if you can dig through the brush, really good recommendations here.

[pastry_chef]

About 20 years ago a buddy hated his Edelbrock cam. He ripped it out, my suggestion dropped 1.5 seconds off his quarter mile. Granted he was around 9 to 1 compression, engine liked the short seat timing / higher area (lift). Today I could do better still.

[TAQuest]

Teardown picture below. How's it look?;

https://share.icloud.com/photos/0arx...r_Township,_MI