I have a question for you guys...

This spring, I caught the racing bug and all summer I've been bent on getting that extra tenth or two out of my Camaro. It does run pretty stong as it is, but I want a little more out of it.

Over the winter, I was planning on replacing the intake manifold on my car from the old single plane Torker to a newer Perf RPM manifold, because the 350 I'm running isn't nearly wild enough to make much use of a single plane intake, although it does run well with it. Its got about 8.5:1 CR, 993 heads, a mild cam (not sure if its stock or not though, but very mild). It runs around 95-99 mph across the lights, depending on the weather and my driving ability that day, lol.

But this is what I got to thinking about today... I'm running a stick car at the track (Super T10 4-spd), and I am using a vacuum secondary Holley. Its a 3310, 750cfm.

But what I was wondering, is would I see much benefit by ditching the 750 VS carb for a manual secondary 650?

What I was thinking, was that I could definitely see some benfit by going to a manual secondary double pumper carb, but was considering using the 6210 Qjet replacement (650cfm, double pump, manual secondaries, spread bore) because then I could also ditch the 14x3 open element air cleaner and reuse my HO dual snorkel air cleaner with the double pumper and get some cool air in there.

...and since I am getting a new intake manifold anyway, I could just get one meant to work with a Qjet (I think edelbrock makes an RPM for the Qjet?) so it would work with the 6210 double pumper.

Basically what I think I'd be gaining from these changes is an intake manifold better suited to my engine, a carb thats better suited to use with a 4-spd, and the ability to get cold air into the engine.

Your thoughts?

 

I'm not qualified to make any carb recommendations, but here's an interesting article on cold air induction vs. no element underhood air. I'd love to see some of you guys use your track time to test f-body dual snorkels vs. open element.

http://www.carcraft.com/techarticles/56419/

 

You can get the RPM in a spread-bore type (7104), but not in the Air Gap style.

Although I don't have a manual tranny, I realized gains with both the DP and cool air induction (which I'm sure you've heard before).

I've never had much luck with the Holley spread-bore carbs, but I haven't messed with one for over 20 years. I'll freely admit that I wasn't too up on tuning one back then, though. RB loves them, and he's much more savy than I.

 

First off, throw everything you've ever read in ANY car magazine out the window as they dont have any realistic info that will benefit you on the track. Racing defies any logic and simplistic math formulas, especailly when it comes to carbs.

Simply put, most of the races at any given track are shoe polish races, so your shooting for consistency between rounds, not fast ET. The biggest hurtle your going to face is accepting the fact your car may be slow and often you have to tune for consistency which will result in slower ET/mph....after you can fully accept that you can move onto stage 2 which is tuning to be competative and winning races...if your tuned to go fast first and consistant second, you will not go very far and only way you will win any races is with alot of luck on your side.

As for your car, stick shift is the worst tranny for competative shoe polish racing. There is just no way to consisteantly hit the same rpm, same staging spot EVERY pass ALL DAY LONG. You may be the best boat rower in the world on the stick, but eventually the math will catch up and you'll miss a shift here or there or miss the shift point and your done-simple in your face realistic answer. You may have fun, but constatnly losing will get old.

a mechanical secondary is a BIG step in the right direction, anytime you rely on something to operate with vacuum to motivate your car, your setting yourself up for losing a consistency race since everything will have an effect on how the carb reacts. Forget the 650DP, step into the 750DP and be done. I ran a similar motor when first starting out and it got quicker/faster with every jump in carb size and also more consistant-that's just racing since your asking for 110% out of your motor you need to be set up to allow it 110%.

Forget the spread bore, get a standard, tried and true Holley carb since 1. almost everybody around you in the pits runs a standard holley carb so parts will be abound as well as tuning advise/help. 2. There is somethinig to be said in racing being a follower. Look around at the parts the other guys having success are using and use them, it will get you a step ahead with less headache. I started out personally wanting to try something different/out of the norm, but it costs alot of time and money swapping parts and tuning when you could just get a similar set up known to work and be 3 steps ahead of the game and that much closer to the winner circle. Having off the wall parts is going to make your racing venture a uphill battle since 90% of the guys in the pits run standard stuff. The other 10% are on their way home on the trailer thinking about what they're going to change for next time.

I would personally stick with the open plenum and 750DP. The open plenum will help take away some of the hit when you take off so you wont have to deal with traction issues on hot greasy tracks and inconsistant 60' that will casue you to lose also. Torque is great, but not in bracket racing since torque is what causes tires to get over powered, chasis's to get over powered and leaad to traction problems which are a bad thing. Try to build your motor for hp so your up and running before it comes into the power band, you'll be alot more consistant that way.

Long post, but having been there done that, trying to help you save time, money, effort by fast forwarding you to where you need to be to start winning quicker.

 

At least I can say I've graduated up to "Write On/Wipe Off", and NHRA # decal on the car...

 

When I take the Camaro out to the track, I go on the 'street legal' days, which is only heads-up racing, not bracket racing. When I'm racing, its usually just with friends or trying to beat my best ET or mph. I really don't take it as seriously as alot of people do. I drive a stick car at the track just because its more fun

Anyway, the car actually is pretty quick for what it is, but I just want to get a little more out of it. The thing is though, I still use the car all the time on the street, so I don't really want to lose any driveability. Thats part of the reason I was thinking about using a 650cfm (as opposed to a 750cfm) double pumper and a dual plane intake instead of a single plane like I have. The intake I have (Torker) seems to need to spin up too high for this engine to really work well with it. My 350 runs out of steam around 4500-5000 because of the cam and heads its got.

I don't get any of my info from any car magazines, because I very rarely read them, and take the tests with a grain of salt most of the time anyway.

Most of the info I've gotten has been from others' experiences... like other guys at the track, or some of the more knowledgeable racers here at TGO, like Five7 and RB.

I know theres benefit to a good cool-air induction system, because I've seen it out at the track. Going from a open 14x3 to a sealed cowl induction system made a noticeable difference for one of my buddies.

I also know theres benefit to using a DP-style carb on a manual trans car, because when you lose the load on the engine between gear changes, the secondaries on a vacuum secondary carb will close and you have to wait for them to open up again. A DP-style carb just yanks the secondaries open when you stand on the loud pedal.

I know thats the theory about why they work better on a manual trans, but I've also seen the difference too. Same guy who I mentioned above also changed from a 750cfm Holley VS carb to a Demon 750 DP, and he loved the change it made! ... so I do know that it DOES make a difference.

 

If that's all your doing is grudge/fun racing, just strap on the 750DP and you'll easily get the .1-.2 possibly more, and if your running out of steam by 45-5000, just get a standard performer intake since you dont need the added range the rpm will give, ebay has them pretty cheap around $50 so you might even pick up a full .3 after your said and done, but the carb will be the big factor.

And dont be fooled about driveability. I street drove the pizz outta my old 355 with the 950HP strapped on top. It's all about the tune, you could just as easily bolt on a 500cfm carb and have the car running like crap as you can a bigger carb. The bigger carb will allow more pull in the higher rpms, I know this personally from the 6 carbs I tried varing from a 600Vs upto my 950HP with no other cahnges made. Later after carb changes were complete I swapped out the performer rpm I was running for a vic jr with 1" 4 hole spacer and it went from falling on it's face at 5500 to pulling well past the 6000 mark.

Borrow a bigger carb, tell that buddy you'll put it back to where he had it jet and PV wise when your done, bolt that on and tune it....you'll see what I mean and save yourself alot of unneeded time money swapping everything out that you have planned. Having been playing this game and trying out many different combo's over the years, my info is first hand...

 

Don't get the wrong impression, I don't doubt that you know what you are talking about

I know the engine I have now doesn't really need an Edelbrock RPM intake, but I'll be building up a decent small block sometime in the future, and would like to use that as part of that engine as well, So even if its a little overkill for this engine -- which, right now, makes a decent bit more power than a stock L98, because I do outrun them (L98 f-bodies) often at the track, and have a much higher trap speed then they typically do -- I can use it on a little bit hotter small block later, possibly next summer.

I'd really like to borrow a DP to try out, but the only two I know of are always in use. The Demon is a chokeless, 750cfm DP thats just set up much to wild to bolt on an retune to work on my engine. And plus, from what I've seen with that one, it seems like Demon carbs can be an absolute nightmare to tune compared to a Holley. He's always using it out at the track when I'm out there anyway, so I'm a bit out of luck there. More-or-less the same story for the other as well, although its a Holley and not a Demon.

I was talking to one of the local guys tonight though, and now I'm wondering if I would be better off to use a 4150 (square bore, dual feed) double pumper instead of the 4175 (spread bore, single feed) double pumper?

See, I already have everything I'd need to use a 4150-style carb on my engine, since my 3310 (750 VS) uses all the same parts... the dual feed fuel line (uses a DP line because its got a secondary metering block, not plate), air cleaner, intake manifold, any and all linkages, electric choke setup, etc... As far as I know, I'd have to change all of that except the air cleaner to use the spread bore double pumper. I also have a bunch of spare parts for a 4160 around as well, and as far as I know, alot of them are the same with a 4150.

Any thoughts on this?

 

Stick with a 4150!!!!! They are common to EVERYBODY, EVERYWHERE!!!

If you know your going bigger mill in the future, again, minimal cfm carb would be the 750DP so your not buying 4 carbs and borrowing 2 like I did You'll be really surprised at what you can get away with on the street so keep looking ahead like your doing and buy parts now your going to reuse in the future.

Personally i'd just throw a 1" 4 hole on your torker and look into a vic jr for future engine then reuse the 4 hole spacer and your set. I wish the motor would'nt have blown before I could've got number on the performer rpm to vic jr swap, but seat of the pants it was just as strong down low as it ever was and it definately pulled harder and higher than ever before with the dual plane intakes. I had the performer, performer rpm air gap, and then vic jr, all bolted on the same 355 with 9.3:1 compression and .480/.480 230/230 hyd flat tappet cam

Demons are notoriouos for a lean condidtion in mid rpm range (or so I was told by engine builder that dynos all of his motors prior to customer pick up) they've tried tuning it out and have made it better than box stock, but smart money is a standard Holley 4150 carb since parts are abound and they're easy to tune...plus they flat out work.

 

If I had room for a 1" spacer, it would be on top of the carb so I can use the HO air cleaner

I think you've got me convinced on using a 4150, but I don't think I'll be using a big single plane intake like a Vic Jr. As much as this is a track car, its also just a car to screw around with on the street, so lots of low end torque is something I like. For some reason, my Torker does have a decent amount of low end power for what it is, so it will stay there at least through the winter. I'll make a decision about that in the spring.

Is there any kind of cold air system that will work with a dual feed Holley? I don't really want to change the hood, because I just won't have the money for that. And the HO air cleaner doesn't clear the float asjustment nuts.

 

I run a 6210 and it works great for me. Also run Weiand 8000 medium rise dual plane with the dual snorkel L69 cleaner and I have very minimal hood clearance. That is something you should check out........................

 

How close is "minimal"? And how tall is that manifold?

 

I'm not famliar with the 6210 carbs, but so long as it takes standard holley parts it might be worth looking into, just dont get too out of the norm since proven pieces are proven for a reason.

My best bud used to run a torker II on his sbc's and with every different motor he went through ( literally) that intake seemed to prove the best of both worlds from an off idle to upper rpm stand point. You will be leaving some on the table not being able to use at least a 1" 4 hole, but having been in your shoes using stock components I absolutely understand where your coming from, sooner you can afford at least a 2" minimum cowl type hood the better of you'll be in this quest for drag racing streetability since intake/carb/spacer combo's will net you quite a bit of bang for the buck. The torker does'nt have the straighter "longer" runners that the Vic jr has, but the vic jr's runners are very short when compared to actual race only intakes so it allows better low rpm response especially when coupled with a 4 hole spacer. I know from the outside looking in it seems like too much, but in reality it would be a great purchase for a bit hotter engine in the future and would'nt hurt you as much as your thinking from being brainwashed by magazine articles.

From a consistency and possibly better ET/mph stand point, any time you can isolate intake charge with a cool ambient source as opposed to sucking in the heated air our cars produce alot of you will be better off. I personally did not see any track differences when I went from standard cowl set-up to completely closing off engine bay air by making a carb pan to seal against bottom of hood to only allow ambient air to be drawn into carb. I have spoken with 2 others in the past few years that have stated a .1 increase in ET once they sealed the cowl to carb, but they were on different body styles (G body and vega), so from first hand stand point I did'nt see as much as others have claimed, it might have helped in consistency but any gains were so minimal they really did'nt jump out and say, " hey this mod proved worthy".

As far as you HO cleaner not clearing, if your gonna keep that peice just mod it to work if your bound and determoned to keep it, otherwise sell it and use that money to go for something worth while. We've had air cleaner bases in the past with similair issues of hitting float bowl adjustments, but nothing a little heat and ball peen hammer did'nt fix....boils down to how much you really want the HO set-up, but in reality if you want to go faster, that thing is wasting your time and energy....how many truely fast cars have you seen with a HO dual snorkel.....see what I mean...

It boils down to priorities and commitment and what you really want to do with this ride. Sleeper, all out pro street, pro touring, drag, auto cross, daily driver, etc....pick your posion and run with it. Do like I did, ask everybody for advise/opinons, sort out the bull sheeot from the real stuff and form your own opinons and run with them.

 

measurements are as follows...front 3.75" rear 4.63" port size 1.94 hi X 1.24 wide with EGR and divorced choke well.See weiand for all info.Minimal would be .....I had to cut insulation out on hood but I retained the stock L69 air cleaner. This carb is an excellant performer but the floats are not externally adjustable and iit is a different animal than 4150/4160. There are 3 on Ebay right now with the highest one priced @30.00. Add 30.00 kit and a small assortment of jets and powervalves (which are standard Holley issue)and you are in the game.

 

ramair.com has units that will clear the bowls.

 

Not being able to use my HO air cleaner is not going to be a devastating, heartbreaking loss to me, as I'm not using it at the moment anyway. I'd just like to make use of it if possible, since its a basically free mod for me, because I already have it. On top of my Holley now is a 14x3 drop base air cleaner with a K&N filter on it.

I'm kinda trying to go the sleeper route with my car, because I know the kind of negative attention fast looking cars get (the kind of attention that flashes red and blue ) and I like the way these cars look unmodified, although a 2" or 3" cowl is an option, because I do like they way they look.

For the spring, I already plan to replace the torque arm with a chassis-mounted tubular one, get some better shocks, install a Hurst shifter with a custom linkage made with aircraft rod ends, and a few other things. It will look stock from the outside, but will stick like glue if it works out the way I'm hoping. I want to replace the carb and intake (and possibly use the HO air cleaner) to get the most out of the engine thats in there now.

As far as I know, the 6210 uses most generic Holley parts, like power valves, jets, etc.. so tuning isn't too bad. I don't know about gaskets and those kinda parts though, but I'm guessing most will be different from a 4150 or 4160.

I know the 6210 has been around for years... since the early 1970s, and I know of a few people that just love them, like RB, but I just don't know how they stack up (overall) to a 4150-based carb.

 

Will the 6210 work on the factory aluminum intake manifold that the HO cars came with? I know it should, but does anyone know for sure?

I've heard that that manifold is actually a pretty good one to use on a fairly mild 350 like mine. It would save me a good chunk of change too, if theres little to be gained by spending $200 on an aftermarket manifold.

 

If you have a rev limiter try holding the throttle to the floor , or just lifting it a bit while shifting. that way the vac sec will stay open during the shift. Put a block under the clutch petal that limits its travel so the clutch just disengages when you depres the clutch against the petal block.
this will quicken your shifts and eliminate any imagined or real secondary throttle action delay that could be effecting the et. I'll bet this improves your et more than any benefit from a dp carb of the same size.

A dual plane manifold can tolerate a bigger carb than a open plenum manifold. You'll like the performance of the performer rpm. Change the intake and modifiy the carb and driving method. If you have too much torque at launch you can kill off some wheel spin by selecting a too light sec spring. Or get tsome tires LOL

 

I don't have a rev limitter (unless you consider a tiny stock cam a 'rev limitter')... all my ignition system consists of is a stock vacuum advance HEI with a curve kit and a coil with a little more bang.

Driving style I'm still learning, so with any changes, its easy to adapt to them because I'm not 'set in my ways' yet. I do want lots of low end torque out of this engine, and thats alot of the reason I've been wanting to use a dual plane manifold. I do race the car, but like I said, its still mostly a street car, and any racing I do at the track is just fun runs and grudge matches. Nothing too seriously competitive.

Does anyone know how good the stock aluminum intakes are? The ones that came on the HO Qjet cars?

 

The 6210 will fit on the stock manifold. I removed my stock manifold because I looked at the stock vs the Weiand 8000 and it seemed to me that the weiand was taller and had larger runners. Also I have always had great luck with both Weiand and Holley products. The weiand 8000 came off of Ebay for 50.00 bucks and that was a deal. On the 6210 you can retain the stock fuel line routing, and if you get one off of Ebay along with a kit you won't have so much in it that you will lose anything to speak of.

 

Working with the stock fuel line isn't an issue for me... its already gone. I would probably just bend myself a new one though, as I did for the dual-feed I have now.

I already have the factory aluminum manifold that came with the car when I got it, and aside from just a little cleaning up with a die grinder to get rid of some sharp machined edges and a little casting flash, it should run just fine. I've seen some quite fast cars running this manifold (or something similar at least, I never looked to close) and they seem to like it. It doesn't hold them back anyway. One particular Nova I remember was running a smog-era GM aluminum Qjet manifold and Qjet and was running very low 13s all day. On a pretty hot day too.

Do you know if the spread bore Holley's use the same tuning parts as the 4150/4160 carbs? By tuning parts I mean things like jets, power valves, accelerator pump cams, etc...?

 

Yes but that is all. All the gaskets, metering blocks,etc. are very different. The floats are NOT externally adjustable and the pump shooters are anti pullover designs,that will not interchange with 4150/4160 designs. Primary venturies are 1 5/32" and secondary venturies are 1 3/8". There were some 800 cfm units made with center hung float bowls but they seem to be rare or no one turns loose of them.