D0AE-N CC Head Unshrouding

[Don C]

There really isn't a need to unshroud the valves for 351C CC heads that will be used for the street and occasional trips to a dragstrip. You mention reliability, did the previous owner also install hardened valve seats? Valve recession is no myth, I've had it occur on two engines. Cleaning the heads up to eliminate any high points that can contribute to pre-detonation (pinging) is fine.

I have the same heads (D0AE-N) and have had no pinging problems on 91 octane pump gas at altitudes as low as 200 feet above sea level. The only work done on them was minor cleanup of the ports and chambers when I had hardened valve seats installed.

Don't believe the hype you've heard about no low end torque on the closed-chamber Cleveland heads. With the lower 1st gear of the 4R70W and the 3.50 rear end, plus fuel injection, you'll have very good throttle response. Enough so that you should give your son a few lessons on driving a high performance car. Too much throttle, especially going around corners, or when it's raining, can have consequences.

 

[wrobinson]

There really isn't a need to unshroud the valves for 351C CC heads that will be used for the street and occasional trips to a dragstrip. You mention reliability, did the previous owner also install hardened valve seats? Valve recession is no myth, I've had it occur on two engines. Cleaning the heads up to eliminate any high points that can contribute to pre-detonation (pinging) is fine.

I have the same heads (D0AE-N) and have had no pinging problems on 91 octane pump gas at altitudes as low as 200 feet above sea level. The only work done on them was minor cleanup of the ports and chambers when I had hardened valve seats installed.

Don't believe the hype you've heard about no low end torque on the closed-chamber Cleveland heads. With the lower 1st gear of the 4R70W and the 3.50 rear end, plus fuel injection, you'll have very good throttle response. Enough so that you should give your son a few lessons on driving a high performance car. Too much throttle, especially going around corners, or when it's raining, can have consequences.

I do not know if the seats have been changed but that is a great point. The heads have already been cleaned up in the ports but nothing more than removing casting flash and smoothing transition areas from what I see. I plan to run a Blue Thunder intake, 1.750 long tube headers into a 2.5" mandrel bent Pypes exhaust with X-pipe to let it breath. You confirmed my theory on the 4R70W and the low end throttle response, thanks. I think the build should yield a streetable 400-425hp pump gas Cleveland.

 

[Don C]

Yes, your horsepower estimate is realistic.

If you have staggered shocks the Pypes exhaust won't fit, unless they finally came out with a staggered shock version.

 

[wrobinson]

Yes, your horsepower estimate is realistic.

If you have staggered shocks the Pypes exhaust won't fit, unless they finally came out with a staggered shock version.

Yes staggered shocks. Did you have a custom exhaust done or is something available in the aftermarket?

 

[Don C]

As far as I know nobody makes a 2-1/2" exhaust for staggered shocks. Most members who have a 2-1/2" exhaust had a local shop build it. I believe a couple of members put together exhausts with universal systems.

I don't know how much work it would be to modify the Pypes system. As far as I know, none of our members have tried it. I've thought about it, but a local shop has the equipment for mandrel bent exhausts, and seems to have decent prices, so I'll likely give them a try. I currently have a 2-1/4" exhaust in good shape, but if I ever get my new build finished I'll want to upgrade.