[Rar_421]

Are this cams compatible with 4.980 valves and 1.6 Installed height? I realize everything thing should be mocked up and measured but just wondering if it's a complete no go,like a Ra 4 cam in 7.6 cr 350

[Cliff R]

Not enough information.

What heads. What springs, retainers and valve seals. Were they machined for P/C seals. How much distance between the bottom of the retainers and top of the valve guides/seals?

A stock set-up is limited using stock retainers because they have a lot of material on the bottom side to seal the factory "O" rings on the valve stems. There aren't too many valve springs out there that will allow a lot of lift and still use the stock installed height or even 1.600".

To get answers you need to tell us what you are trying to do?......

[25stevem]

Besides the duration of that Cam being too much for a 350 on the street, no less a 7.6 to 1 350 cid motor, the lift is too much for the stock valvetrain set up!

The 4.980" is just the overall valve lenght needed for the deep chambers of the low compression heads, the Intake valve lift of that 703 Cam no less the Exh side lift is too much for the stock set up.

That Intake lift is .489" and the most you can safely run with a stock valvetrain is .470", and even at that lift if the stock springs where new they would not last long!

I myself even with 9.5 compression in street 350 motor would not run that Cam even with Rhodes lifters!

It would be a dog!

[Rar_421]

Sorry I wasn't clear in my post, didn't have all the info,the heads are at a shop the owner had to have back surgery and will be in rehabilitation and is outta work for a while and asked the shop to sell them and get what they can to take care of the bill and whatever extra goes to the owner,today I received a callback with the following info
Number 11 heads
2.11 intake,1.66 exhaust
Hardened exhaust seats
Guides cut for Pc seals with bronze liners
Crower springs 68404& retainers 87048,I guess these came in a kit with lifters but I'm wasn't able to access crowers site on my ancient phone for the p/n number,I guess the short block is spoken for but it has a different cam in it so I just assumed over the weekend that the 703 maybe had to much lift,seems the hotter cams have longer valves from searching for info on the site ,but I was told today they talked the owner into a milder grind as the engine was slated to go into a 54 jimmy with 3.08 gears

[John Milner]

I am actually running the Lunati 704 camshaft in a 455, which has lift numbers of .504 .527 on some 6X heads that I set the springs (68404 Crower) up at 1.6. Things get really close when you get up close to .500 lift on a 1.6 install height on Pontiacs. In my case, I cut the valve guides for positive type seals, which reduced the height of the guide some and I was careful to measure seal to retainer clearance. I used stock retainers but surfaced the area that normally supports the factory o-ring valve seal down to gain some clearance. It is close but it works and has worked for years.

To answer your question, you need to measure your guide/seal to retainer clearance before you can say if your cam will work for you with stock valve lengths.

[Steve C.]

That Crower 68404 is rated 113 lbs on the seat at 1.600".

https://www.crower.com/valve-springs...set-of-12.html

Evaluate what the pressure will be with the Crower 68404 valve springs at your actual VERIFIED installed height. With that in mind take note that based upon his dyno testing and extensive use of Voodoo cams Paul Carter recommends 130-135 lbs seat pressure with 30 degree seats and 330-340 lbs open pressure with the Voodoo hyd flat tappet lobes. Less pressure with 45 degree seats. Also he suggests to keep the distance from coil bind around 0.100".


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[25stevem]

Those 68404 springs when set up with a 1.600” installed height and the needed retainer and cut guides will be easily good for .575” lift .

If those number 11 heads still have pressed in studs you would be risking snapping them off at the thread to shank area or yanking them out with the spring pressure needed to run over .480” lift.!

I know as I have had both failures take place back in the mid 70s.
The problem is what you will have left for valve lift once you shim those up above the 115 psi seat pressure to handle the 2.11” valve as needed.