I posted some info on this motor before, but now have more facts to play with to try and find the best carb/intake combo.
- - - - - -
400ci;
Bored 30 over (best guess based on pistons);
76cc cast iron heads;
1.5 rockers;
TRW 400NP 30 cast pistons (recessed head .160") and molychrome rings;
Crane Energizer cam (lift I/E 480, advertised duration I/E 284, duration at .050 I/E 228) 2800 – 5800 performance range;
Holley 750 dual feed – vacuum secondaries, plugged power valve;
Torker II single plane intake (2500 – 6000 rpm performance range);
Compression between 135 and 145 psi all cylinders;
Unknown head gasket. Federal Mogul 4926M 10 (on build receipt, but not sure if that’s the head gaskets);
Guessing stock valves;
Guessing around 9.0 – 9.5 compression;
Ram horn exhaust to stock sidepipes.
- - -
Appears to be setup for higher RPM performance.
I’m trying to achieve the best low end torque, and it doesn’t seem to come in until 2500+ RPM’s.
Should I go with a dual plane Performer - or the RPM or Airgap if they’ll fit under the 427 BB hood – stay with the Torker II - or other suggestions.
Is the 750 Holley the right size and would a double pumper work better (I’m at least going to replace the power valve and re-jet it to meet these specs). Smells rich at idle and only fair idle quality at the moment.

:cheers:



[Modified by Chris81, 10:30 AM 8/24/2003]

 

Are you running a four speed or auto? If you're running an auto try a higher stall converter. Everything seems matched up fairly well. If you can lean out the idle some you may notice better lowend response. A friend of mine ran a 400 nearly identical to this but with a 292/488 cam in a 68 Nova. He later swapped the converter to a 2800-3200 stall and the thing seemed like a totally different car. If I had to change anything in your situation it would be the intake. try the Rpm or even the holley 300-36 Z-28 style. Nearly any dual plane will increase low end vs. the torkerII.

 

Torker II is a single plane I believe, switch to RPM Air Gap probably the best dual plane out there right now, will give you a little more grunt but not much you can do if the cam's power range is ~3000 + then that were it makes power.

 

Weiand Stealth is also a good dual plane. With headers you would gain some low end grunt too.

 

The Performer is good for 430+HP on 383+ & you should have room for an insulating spacer. Stealth is good. 750 is fine. You want to look at entire intake flow path & not have the top of the air filter too close to carb.

Better ex. rec.!

RPM fits good w/ aftermarket drop base filter & 73-79 med. rise hood.

:cool:

 

Absolutely go dual plane. I run the RPM Q-Jet with a 750 Holley and the torque is outrageous.Check out my website.

 

I don't know what to expect with shorties that'll hook up to the stock side exhaust. Doesn't seem like I'd gain that much over the ramhorns in that little bit of distance. I had full length headers on the last car (ZZ4) and it was well worth it.
http://www.c3vettes.com/69_engine_pics.html

Ganey... The air flow with a drop base was another concern. I have the 427 BB hood, but it doesn't offer a ton of clearance. I'll need to get out the clay and see what I've got left with the 3" filter... The Torker II measures 3.53 x 4.63" and the Air-Gap measures just slightly higher at 3.72 x 4.92" and the RPM is 4.20 x 5.25". I'll probably need a drop base for the RPM...

Money Pit... Nice info on your website. I see you're using the same carb, albeit not hacked up like mine... The choke housing has been milled off, so if I need to go with a drop base to use the RPM, that may be an advantage. Have you tried a mechanical 750? Just wondering if being able to change out the secondary jets is a benefit.

Wow... Just went out and measured remaining clearance, and I have 1.125" to spare with existing air cleaner!!

Thanks guys... keep 'em coming! :cheers:


[Modified by Chris81, 1:36 PM 8/24/2003]

 

I think a 750cfm may be borderline too big, but with vac secondaries it should work. Holley has a formula on their site to calc this like

ci X max rpm / 3456 * efficiency

 

Old school guy talking here. Also a guy who is NO FAN of Edelbrock products.

IMHO, the best-ever dual-plane intake for a Small Block Chevy is the Holley Street Dominator. And, for your 406, I would go with an 800 CFM carb. (Or install a Proform body on your 750.)

I'd consider a little more cam down the road if I were you. 400s aren't 350s--big cubes like big parts. Look at something in the 235-240 deg. duration at .050" as a minimum. Get up into the .515"-.525" lift neighborhood, too.

You'll still have a very smooth-ish idle, good vacuum and you'll be making enough power so that you will really notice headers if you should install them later.

 

If you can.. try AFR 195 heads. With a higher port velocity you will recover
a lot of that low down torque. Should make a huge difference.
RPM Air gap if you can fit it under your bonnet, will also help a lot being a
dual plane. The RPM Airgaps are also great up high in the rev range.
The last big torque improvement is EFI but thats a bigger step.
Chris.

 

With the last two replies... the cost of 'fun' just went north! :lol: After looking through the various forums (not just Corvette), it seems that there is great praise for the Weiand Stealth manifold. It's not that much taller overall than the Torker II and has a good RPM range. Holley claims a range of 0-6800 rpm's, so why doesn't everybody use these?

 

I think that, now that Holley and Weiand are the same company, the old Street Dominator and the "larger" Weiand Stealth manifolds are the same thing these days. Why doesn't everybody run them? Well, some folks need EGR fittings. Other folks want to stick with the Q-Jet. Other folks are suckers for whatever is new, trendy and more expen$ive because of extensive mega-dollar advertising in ALL the "Not Rod" magazines.

 

The DUDE:

Will the Street Dominator fit under a stock '69 SB hood? Will a Sreet Dominator and Holley carb? Or will I need a drop-base aircleaner to fit? I recall that a Weiand Action + will fit, with a drop-base aircleaner.

I do not want to find out the hard way and end up putting a star in my hood.

Also: what is the difference between a Holley Street Dominator and a Holley Contender? Will the Dominator work with a mild sbc (headers, mild cam)?

thanks in advance,
Kevin

 

I know the Street Dominator/Holley combo will fit under a stock '76 hood with a drop base air cleaner. But I think the '76s have a slightly more pronounced hump than the '69s. It will be close either way.

Street Dominator vs. Contender? Well, I don't think Holley makes "Contenders" any more. The Street Dominators (P/N 300-36) will supposedly operate just fine from off-idle to 6,800 RPM or so as far as I recall. I spin mine up to 6,000 and have never seemed to nose over. And it's your basic dual-plane off-idle.


[Modified by The Dude, 8:32 PM 8/25/2003]

 

Although it's from the 'dark side', this may be a pretty good representation of various intakes on a BB with a mild cam and stock Holley 750 - 3310 series..
http://moon.ouhsc.edu/jjoice/intakes.htm

 

Here's another informative link that pretty much covers intake manifolds and carb sizes.
http://victorylibrary.com/mopar/intake-tech-c.htm

On the subject of carbs, I may rebuild the 750, even though it's got vacuum secondaries, and wondering if anyone has tried the Proform main body?

 

Thanks for the help, um, Dude. FYI, I called Holley, and they said that the Weiand Action Plus and the Holley Street Dominator are the same height.


[Modified by Kevin Mason, 6:19 PM 8/27/2003]

 

Really? I'll be the first to admit that I haven't kept up with all the developments at Holley since it acquired Weiand, but I seem to remember that the Weiand Action Plus was a low-rise stock-type EGR replacement similar to E-Brock's non-"RPM" Performer manifolds. And that pretty much every other intake Weiand makes these days is called a "Stealth." But if Holley says the carb pad-to-end rails dimensions front and rear are the same between the two I would defer to them. Also, if those dimensions are in fact the same, you shouldn't have any trouble getting the Street Dominator/Holley combo under your hood. Great news.

 

I want to defer to what Holley says as well, but I admit being a little nervous simply taking a customer service rep at his word. Since customer service is nowadays not viewed as contributing directly to the bottom line, companies often try to avoid spending money on this function, and simply hire any jackass off the street. We've all seen the results, but this guy, I admit, seemed to know what he was talking about.

One reason I prefer to buy parts from a local speed shop, and to have machine-work done locally. If things go to poopie, I know whom to blame.

thanks again.

 

OK, the phone monkey at Holley was either feeding you a line of B.S. or he was smoking crack. I just dug out a Holley/Weiand catalog I picked up last November at the SEMA show.

The Weiand Action Plus intake for SBCs (P/N 8004 or 8024) has a front height of 3.5" and a rear height of 4".

The Weiand Action Plus for SBCs (P/N 8000) has a front height of 3.75" and a rear height of 4.63".

The Holley Street Dominator I'm talking about (P/N 300-36S or 300-36) has a front height of 4.44" and a rear height of 5.33".

These measurements are taken from the mounting surface on the bottom of the manifold(s) at the front and rear end rails to the top of the front and rear portion of the carburetor pad.

Looks to me like Phoneboy just wanted to sell you something. Like, now. I'll bet if you called his sorry azz and asked whether Weiand P/N 3984 would fit under your hood with no modifications, he'd tell you that it's a sure thing.

(3984 is a 10" tunnel ram, BTW.)

Good luck, man.