CHP magazing has a buildup of a 406, with AFR 180cc heads, 230 deg Lunati cam, 1.6 rockers, RPM intake, and 750 holley. This sucker makes 525 lb-ft at 4100 RPM and 490 HP at 5600 RPM. Those are awesome numbers at real street-usuable RPMs. I love it. Especially because I have a '73 standard bore 400 SB sitting in my basement. I think it would make a real nice future motor for my 68.

However...

I'm not a hard-core race guy. I'm more of a cruiser and weekend warrior. I don't want a highly modified, racey looking machine. I'd want to do it as a semi-sleeper. That means I don't want to jump to a BB or L88 hood. I've read the threads about which intakes work with a drop-base aircleaner, and although the RPM has worked in a few cases, I might have to consider a lower intake. With this much power and torque on hand, I think I could live with the outcome, even if performance take it in the shorts a little. That's my question for you motor builders...

How much power would I expect to lose with a Performer EPS, Weiand Action Plus, or something similar? I doubt I'd see much change in low-end torque because the RPM is already a pretty decent piece out of the box. Another alternative is the Torker II, which is similar in height to the Performer EPS. In a way, the single plane might be a decent option. With all the torque and airflow of this 406 (over 500 lb-ft at 3300 RPM), a small drop off in the lower revs might be acceptable. I'd imagine the drop would be quite a bit less than with a 350 because the airflow at any given RPM is so much higher.

What's my best 'short engine' combination?

This is a classic Corvette design issue. Remember when the 427/435 engine was changed from 67 to a lower intake for 68?

Just curious for your opinions.

 

Hey I'd go with the Torker II setup The 400 is going to be a torque monster and the single plane might even make it spin up a little bit more

 

if not i'd use the rpm air-gap

 

I think its been discontinued but should be around s/h. Miles ahead of the Torker II and same height. Lengthen runners as per David Vizzards book in Carbs and Manifolds (he likes this manifold) to boost low and mid range.

I used an old single plane Holley Street Dominator years ago and it had plenty of midrange.

 

Super Chevy mad did a comparison test between a Weiand Stealth and an RPM air gap. The air gap made 10 HP more at 2200 RPM and 24 HP more at 5500, and 6K. The stealth is a low manifold.

 

I'll admit to having been a fan of the torkerII, but not anymore. The area of the runners are the smallest of all aftermarket intakes I have compared. I switched from the TorkerII to a Team G 7525 (discontinued but found on ebay) and picked up nearly 10rwhp from the intake alone. Another one to consider is the even larger runner Team G 7530. The 7525 and 7530 are within .080" of each other in height and both will fit under the 68-72 small block hood. The low end torque loss of these single planes is minimal if any. In fact, I found no difference in seat of the pants torque between a Performer 2101,TorkerII and the Team G on a 355.

 

Was that a recent issue that I could still buy? I'd love to see the details on that! If not, is there any possibility you could scan and post it or email it to me??? I'd sure appreciate it if you could.

 

I've done a little research on the Team G single planes and think they're a nice choice based on the specs. The 7525 is probably the ideal intake for my application. Yeah, I realize they're discontinued but I'll keep an eye on ebay and/or Carlisle. The 7530 isn't bad but the increased port size is a bit of a put off for me for a torquey 406 without intent for 6000+ RPM use. The 7525 ports are 1.94x1.15 (2.231 sqin), very similar to the RPM Air Gap. The 7530 ports are 2.17x1.24 (2.691 sqin). That's 20% larger, and considerable larger than any of the intake I've looked at. I really want to stay with something that can be portmatched with the FelPro 1204 intake gasket, which is 1.990x1.230.

Has anyone had any experience with modifying manifolds? I was wondering how a medium rise dual plane like the Weiand 8000, which has similar height dimensions as the 7530, might work ported out to 1204 port sizes and a cut down plenum divider. Thoughts?

 

Your best all around performance is from a dual plain manifold that works from 0-7000+. Most of the others {single plain} are only effective from 5000 and up.

 

I've read that buildup article.
there is something funny (hmmm) about it, they used fully CNC'd 180AFR heads (cost about $1900 or more) but if you look closely at the intake port pic's you can tell that they have been hand polished (they no longer have the ball-nosed end mill finish). I think they neglected to tell readers about the polishing job.
in past articles they have had a pro polish ports (on even bigger heads) and it amost always add's to the HP numbers (unless the heads are too big to begin with).
I think you should get a few professional opinions before shelling out 2 grand for the 180AFR cnc'd heads.
I'm sure they are nice heads, but I doubt they will make 490HP out of the box (like that article implies).
RJ