[rtanner]

on that note, i know i saw a thread on here where one of the ho racing guys ken? said he measured it and it was like 30 degrees or so but dont quote that its from memory,

[rohrt]

Thanks for posting that b-man.

Were all the HO and RA 1.65 rockers?

Its interesting that the range is from 325hp to 390hp. I would like to sit down and go over the compression and valve sizes with each motor.

A fellow student in shop class back in the day, had one of those 390hp 428 that he was porting the head on. Never got to see it run.

[b-man]

Originally Posted by rohrt

Thanks for posting that b-man.

Were all the HO and RA 1.65 rockers?

Its interesting that the range is from 325hp to 390hp. I would like to sit down and go over the compression and valve sizes with each motor.

A fellow student in shop class back in the day, had one of those 390hp 428 that he was porting the head on. Never got to see it run.

The 068 cam always used 1.5:1 rocker arms, the 1.65 rockers were used on RAIV 400s and early 389 & 421 SD engines.

[Sun Tuned]

Well here's the deal...
I don't know either but I have access to the cam dr measuring machines here in town at all three cam companies. So since I dont have any original cams but do have four of the in the box Spc Melling cams....

I'll pay the shipping both ways and hand deliver them to the adcole machine, I can wait while it's being done if need be.
I'd like to know myself....

[goatwgn]

Originally Posted by b-man

The 068 cam always used 1.5:1 rocker arms, the 1.65 rockers were used on RAIV 400s and early 389 & 421 SD engines.

The 1.65 rockers do seem to work good on the 068 cam, however.

[jimmy daniel]

I bought a new Trans am in 1977. It had the TA 6.6 and 4 speed. I put on #48 heads, 068 cam with 1.65s, headers and 3.73 gear. That car would fly. Idled very smooth

[jimmy daniel]

And I ordered a lot of my stuff from Ken at HO Racing.

[goatwgn]

Originally Posted by jimmy daniel

And I ordered a lot of my stuff from Ken at HO Racing.

HO racing was "The Place" back then to get good quality Pontiac speed equipment. Still have one of their cataloges.

[b-man]

Originally Posted by rohrt

Thanks for posting that b-man.

Were all the HO and RA 1.65 rockers?

Its interesting that the range is from 325hp to 390hp. I would like to sit down and go over the compression and valve sizes with each motor.

A fellow student in shop class back in the day, had one of those 390hp 428 that he was porting the head on. Never got to see it run.

-1964 -

421 HO 370 HP Tri-Power (10.75:1, 1.92/1.66)

-1965-

389 360 HP Tri-Power GTO (10.75:1, 1.92/1.66)
421 HO 376 HP Tri-Power (10.75:1, 1.92/1.66)

-1966-

389 360 HP Tri-Power GTO (10.75:1, 1.92/1.66)
421 HO 376 HP Tri-Power (10.75:1, 1.92/1.66)

-1967-

400 HO 360 HP GTO (10.75:1, 2.11/1.77)
428 HO 376 HP (10.75:1, 2.11/1.77)

-1968-

400 HO 335 HP Firebird (10.75:1, 2.11/1.77)
400 HO 360 HP GTO (10.75:1, 2.11/1.77)
428 375 HP (10.5:1, 2.11/1.77)
428 HO 390 HP (10.75:1, 2.11/1.77)

-1969-

350 HO 325 HP Firebird (10.5:1, 2.11/1.77)
350 HO 330 HP Tempest (10.5:1, 2.11/1.77)
400 RAIII 335 HP Firebird (10.75:1, 2.11/1.77)
400 HO 360 HP GTO (10.75:1, 2.11/1.77)
400 RAIII 366 HP GTO (late year) (10.75:1, 2.11/1.77)
428 HO 390 HP (10.75:1, 2.11/1.77)

-1970-

400 RAIII 345 HP Firebird (10.5:1, 2.11/1.77)
400 RAIII 366 HP GTO (10.5:1, 2.11/1.77)
455 HO/RA 360 HP GTO (10.25:1, 2.11/1.77)
455 HO 370 HP (10.25:1, 2.11/1.77)

-1971-

455 HO/RA 335 HP GTO/Tempest (8.4:1, 2.11/1.77)

-1972-

455 HO/RA 300 HP GTO/Tempest (8.4:1, 2.11/1.77)

[Sun Tuned]

Anyone have any used examples of these cams??

[rohrt]

LOL that saves me some work. Thanks.

[b-man]

Originally Posted by Sun Tuned

Anyone have any used examples of these cams??

I have two NOS 068 cams and one NOS 067 cam. Found all three of them by placing a 'parts wanted' ad here on PY in the classified forums.

I have a used original cam (9770543?) that came out my '64 421 HO, I need to clean it up and take a better look at it. Couldn't find the factory letter stamp to ID it.

[Rocky Rotella]

According to the factory literature I have on the 068, the dwell area at peak lobe lift is 4 degrees on the intake and 6 degrees on the exhaust.

Not sure if the Melling 068 cam is a true reproduction. I know it isn't where the 744 is concerned.

[68azbird]

Originally Posted by Rocky Rotella

Not sure if the Melling 068 cam is a true reproduction. I know it isn't where the 744 is concerned.

I have one I purchased about 15 years ago, will have to check.

[PONTIAC-ONE]

69 428 made 390 hp
70 455 made 370 hp

Is this fairly accurate? 428 had a little more compression but I would think the 455 would out power the smaller engine....

[Sun Tuned]

Rocky that's what I was trying to say. I'm curious if the 068 and 041 versions are true and if so how true a copy of the originals.

If you want to do an article on this I'm up for walking these things through the cam co. To have em checked out. I'd like to know for my own satisfaction. I knew the 744 copy was a dud I did that already....

[b-man]

Originally Posted by PONTIAC-ONE

69 428 made 390 hp
70 455 made 370 hp

Is this fairly accurate? 428 had a little more compression but I would think the 455 would out power the smaller engine....

These are simply advertised horsepower ratings that you must take with a grain of salt.

Quite often the top rating is not to exceed 10 pounds of vehicle weight per HP. Note the Firebird vs GTO ratings for the same exact engine, Firebird being lower because of the lower vehicle weight.

Lastly, HP isn't always dependent on cubic inches. A 428 could have more peak HP, but the 455 would have more torque.

Again, some of the ratings are closer to 'real world' than others.
-------------------------------------------------------
One fun comparison - Do you think a 370 HP '69 -'70 RAIV 400 is equal to a 370 HP '64 421 HO in true HP output?

My money's on the RAIV, out-powering the 421 HO by at least 50 HP. Restored RAIV 400 engines have seen 425 HP on a dyno.

As much as I love my '64 421 HO I doubt it can make the factory stated 370 HP, 350 might be more realistic but who knows.

[Rocky Rotella]

Originally Posted by Sun Tuned

Rocky that's what I was trying to say. I'm curious if the 068 and 041 versions are true and if so how true a copy of the originals.

If you want to do an article on this I'm up for walking these things through the cam co. To have em checked out. I'd like to know for my own satisfaction. I knew the 744 copy was a dud I did that already....

I understand. I was just saying that we know what the real 068 is so if you want to run your Melling through a spin doctor, we can compare it to the real one.

I'm game for an article on that for Smoke Signals!

[Cliff R]

It's been at least 20 years since we've bought and installed an 068 or 744 cam, but back then the Melling replacements had flat lobes and low lift just like the factory cams did. I never ran one on a cam doctor, but the engines we installed the 068 cams in ran very well, and easily managed pump fuel at relatively high compression ratios.

I did pull the 744 cam from my own engine and replace it with an HO Racing HC-01A, as that engine (428 with 6X-4 heads) wasn't making nearly the power that I thought it should have. With the 744 cam it idled poorly, was "lazy" below 3000rpm's, then went "dead" around 4800rpm's. I had plenty of spring on it, but have heard others mention over the years that the 744 cam may have taken the "flat" top lobe design a bit too far and could experience high rpm issues.

It really matters not in the big scheme of things, those are old/outdated designs, and as good as the 068 cam works, there are just much better offerings out there these days that establish more area under the curve without all that duration and having to add high ratio rockers to them, etc and FWIW......Cliff

[Formulajones]

068 cams never got me all that excited. Okay for a stock build I guess but a 45 year old cam design wouldn't be my first choice.

Cliff, your HC-01A looks surprisingly close to the Summit 2802 camshaft specs, with the 2802 having a smidge more duration. How did your 428 run with that HO cam? Complaints, good or bad?