Building this one for another Olds customer.
1970 .030 455 Block. Line bored, .honed, cam plugs, .010 polished crank, Eagle Rods, SRP Pistons (I'll try to provide specs on pistons and cams later), "C" heads, bowl ported, 2.075 Intake and 1.78 Exhaust Ferrea valves, Competition valve springs setup for roller cam, Howards, roller cam, 4/7 swap, Howards roller lifters, new pushrods, screw in studs, Comp roller tip 1.6 rocker arms, W30 aluminum intake (repop), W30 exhaust manifolds, Dick Miller Q-Jet build to match combo.

 

You do realize that rocker is at its limits with the spring pressures needed for a roller cam correct?
And I’m guessing the piston is really a CP and the ex valve is a 1.68? That’s what they look like anyway. Thank you for the build outline!

 

No I did not. That's a good point. Thanks for pointing that out. Yes, typo on exhaust valve. Didn't know the piston was a CP either. Going to check everything here as I go, as all of my prior Olds build have been very stock. Thanks for the feedback.

 

The pistons say SRP, but maybe they are rebranded.

 

Do you have a part number by chance?

 

I'll try to get it when I get home from the office.

 

Anything on this?

 

 

Got it thanks. What’s your target comp ratio? Cam specs?

 

9.75:1 CR. I’ll provide cam specs shortly

 

Here’s the cam specs. 4/7 swap.

 

Idk.
cutlass would know.

but I have sort of the same / bigger set up. I had to go with the bigger/ gold rocker arms. Barely fit under the valve cover too

 

You keep mentioning 4/7 swap, why?
Kind of a small cam. Won’t make much hp but should enhance low end torque.
Thanks.

 

I think I understand what 4/7 swap is referring to, but what is the logic?
TIA

 

I didn't really seek out the 4/7 swap, it just kind of ended up with what we picked out for a street setup. However, I can tell you I used a Howards cam with the 4/7 swap on a Chevy 409, and it definitely smoothed out the idle. That cam was impressive with that combination, and the customer was and is extremely pleased. So I went with another Howards on the Olds to see if the outcome would be similar.

 

My roller cam is a 338, and idles fine,

 

That's good. Just seeking feedback, that's all. This customer is very much a purist but wanted some kick for his 67 442. I wanted to make sure I have enough vacuum for the power brakes. Not trying to set any records, but hoping to make him a nice torquey street machine.

 

That Cam is fairly small for a 455, you’ll have plenty a vacuum.

 

Reading this thread to me is like turning the tv to Univision...

 

So you did a back to back with the exact same cams other than the 4/7 swap and it made a noticeable difference in the idle? What were the cam specs?