Isn't that like the question of questions? The tranny you say? No way! One of the things I HAVE been able to pick up on is that choice of tranny is solely dependent on what YOU intend to do with the car. What the owner's preferences are with respect to fuel economy, performance, rideability, budget or even just the plain old cool factor is what make you choose a tranny that's right for YOU and no one else unless they have the exact same goals in mind. But the TC?! What gives? I know very little about what happens from the crankshaft back... hell... I know very little about what happens from the flywheel forward too . But the tranny and all associated components are like black voodoo magic... just not meant to be played with. How could it be that something like the TC, which REALLY affects the overall useability of the car doesn't have a formula to determine the correct one for your application... or at least a dang good guideline?

I've tried reading up on its function, purpose and selection but keep running into the same vague useless info. Some rule of thumb about choosing one that falls between where your engine produces the most torque. What in the world is that supposed to mean?! Layman's terms for the love of Pete!

Here's my problem... I got my original engine spiced up a bit from a local machine shop run by a guy who has been racing his whole life and is 3rd generation owner of this shop. It has a magnificent reputation here in Vegas and the guy is super nice. He upped the HP of my engine from the stock 210hp to up around 340 or so. One of the things he did was stick in a HUGE cam. Well intentioned, but now I have issues I can't solve and I think it's with this black voodoo magic stuff. Here's my specs... roughly:

- 327, originally 210hp

- flat top pistons for higher compression (don't know what the new CR is because I don't know what size gasket they used)

- original powerpack heads (not camelhumps) that have been hogged out and have professionally enlarged valves to match the camels but still have the 75cc chambers

- The rear gears are stock for the 67 327 with powerglide. I think it was 3.0 or 3.07 gears (one wheeled wonder)

- a friggin' HUGE comp cam http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=296&sb=2 (http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=296&sb=2)

- original 2 speed automatic powerglide (no I'm not changing it out) with stock converter

- Pertronix flame thrower dizzy and coil with 8mm taylor wires and autolite plugs with 18* initial and if memory serves high 30s but I'm not sure about the high 30s... it was mfg recommendations for this

- Vintage Edelbrock Torker Scorpion intake (air gap style)

- Edelbrock 1407 750cfm carb with electric choke

- 4 wheel disk brake conversion (working like crap because of huge cam)

- Summit ceramic coated long tube headers coupled to a Pypes stainless dual exhaust with x-pipe and street pro mufflers

My problem: really high idle... 1200 rpm. Throw the sucker into gear (reverse or drive) and the engine tranny kicks hard as though I just romped on it and it kills the engine. I have to rev higher and throw it in gear for that not to happen and then I have to be ready to take off like a BAT OUT OF HELL!!!! Not that that isn't fun or anything... what can I say... the wife disapproves. This sure sounds like a torque converter yes? According to desktop dyno... I'm pulling my highest torque (just over 350) anywhere from 3000-5500 rpm and the horsepower peaks at 343 at 5200 rpm. But I'm always at high RPMs with the powerglide, and also I was guesstimating on the compression ratio. I set it at 9.0 I believe it was... sorry I’m at work. Don't get to chat at home... kids. So how the heck do I solve this issue when there is nothing to help figure out what I need. This is for what I hope to be a daily driver. Not planning on racing it EVER. This is a family owned car since day 1 and has 100% matching numbers parts throughout except for just a little sheet metal. What components I removed for upgrades I kept in a crate right down to the date coded drum brakes. I will run no risks with it. It is strictly for family cruises and cruise ins. I need it to be street driveable for the wife. It’s her family’s car and she needs to enjoy it. I've asked about 20 people and have gotten 20 different answers. Can anyone clear the fog for me? Also, is it the stock converter that's causing my high idle or do I just need it to make the monster cam happy?

Long... I know... but everyone always seems to want more info. I'm playing it safe.

Thanks

My problem: really high idle... 1200 rpm...............Also, is it the stock converter that's causing my high idle or do I just need it to make the monster cam happy?

From your discroption I think this is what is happening...
For the street/missus to drive....the engine is way over camed and carbed, making it very unstable down low...
You have a stock TC there are 2 one is rated about 1200 rpms the other about 1800...
Either way, they will be both locking in at your rpms, drop into gear and thereis no slip

To get around this , a high stall, say a 2500, better still 3000
BUT doing so, around town most of the rpm range is i 1500 to 2200 ..which means ok once upto speed but the slightest slop/acceration the rpms will go way up and be like a slipping clutch
AND It will improve the neural to in gear only slightly, at 1200 rpm idle..now where enough to satisfy the missus.

You have to bring the idle down....what advance do u have in the dizzy, does the VA kick in at idle vaccuum? is the VA connected to manifold or ported.

Get intial advance up, (if there is room to do so) and you should be able to drop the rpm idle

The carb is too big for a missus driver..this also creates a unstable idle, doesnt help
BUT the cam has way to much overlap duration for a street engine...It is described as "Good for higher RPM tracks" thats not even a street/strip..no way designed for street let alone the missus to drive around town
IT is designed to be real crap idling, cause that is NOT a consideration in the design, it is not designed to drive up the road, unless going out of the pits...it IS designed for on the track full trolttle hard out ONLY.
THAT is your main issue.
Even advancing that cam up todrop rpm range will not even get close to street drivable .

Also that engine, on the street will cost a fortune to run, and the missus will soon complan that she has to fill up every time she goes to the shops.

Did you tell the engine builders what rpm range and what the car was going to be used for???

What has happened is what damn near everyone has done on their 1st street engine, and come a cropper...gone for the high end HP instead of bottom end torque...a stump puller.
I have gone extreme stump puller cam (advanced ) low duraton overlap, small carb, cast rams horns, and stock 1200 torque converter I swaped the 2500 out, lost a bit of acceration below 2200 rpms off the line, but put the boot in from about 40 mph cruise and she takes off, yet still very quick below that also, I swaped the 2500 cause it spent most of its life slipping around town, and improved economy dramatically
I Do run near 11:1 compression, but Im running 105 octane gas, and because of the gas have an idle of 600 dropping to 450/500 stable in gear. 308 gears

Dario,
The best way to choose a torque converter is to decide on which manufacturer you want to purchase, then pick up the phone and call them and ask. Make sure and have as much information about your engine and car and let them tell you which one to use. There are too many variable involved to try and guess.

That cam seems to be a REALLY poor match to your setup, and is really the root of your problems. Hard for me to believe a respected engine builder would recommend that cam on a low compression 327 with a PG and 3.08 gears. I'd worry about converter selection AFTER I got that cam replaced with something more suited to your set-up. Yeah, you could put a 3000-3500 stall converter in and solve part of your problem, but in my opinion that's the tail wagging the dog. As Steps said, get a cam that operates in the RPM range you're going to use on the street. If you do fhat, I bet you'll be happy with the converter you have. And consider this - a cam change at this point will probably cost you less money than a converter change, or at least darn close.

That intake manif isn't the greatest choice for a 100% street car either. You can find an Edel Performer on e-bay for 50-75 bucks, and would be a much better match after the cam change. The carb, although a little large for your motor, should be OK, being a vac secondary carb.

I hope the guy knew what he was doing when he ported your heads. It's pretty easy to ruin flow characteristics if you don't. It's a bit more of a science than "hogging them out".

Good luck!!

Well,

Hogging out would be a poor choice of words I guess. I was an ESL (English as a Second Language) kid... leave me alone hahahaha. He knew what he was doing. As for the cam choice... I asked him for a bit more power. He told me he would get me to the 300 hp range and was intending on putting a cam in that was cut to reflect those of the early corvettes of that era. I had no clue what I was getting until I had the idle issues and I looked in the teardown/breakdown of what he did and found the cam specs... but even then I had no idea what I was looking at. I wanted a stronger engine that would be fun to cruise the town a couple days out of the week, and maybe still have enough power to lite em up every now and then. I thought we both understood eachother. I'm not an engine guy. I'm an electron chaser. I have fun in zapping myself not making pistons go up and down faster. Well, the car is a long term project. I turned in my engine and got it back over a year ago and only recently ran it and broke it in. I'm just now realizing this. In other words... too late. I can't afford to be replacing a cam now. With it will require new springs and lifters and all kinds of things I'm completely ignorant about doing. Unless one of you guys wants to drive down and give me a hand I'm stuck. I wont touch it with a 10 foot pole. I had asked before about bad idling problems in the engine forum but back then I was running my stock intake and 2bbl carb with this set up. I know 3000 RPM around town seems high but the powerglide sits at this all day long. Actually more like 3500 because it's only got first and second gear. So, realistically, IF I were you guys and knew what the hell I was doing I would replace my cam again with a stocker. But I just plain don't have the know how. If it were just the cam... that would be something, but I'm sure this guy changed the springs, which probably affects valve length or something which will later affect something else and so on and so on. I need to figure out what will improve the way my car responds to the throttle and my idle if at all possible the way it sits. I'm on a humoungous budget now that times are tough (I work for the airlines, what can I say... I could be out of a job tomorrow for all I know). Let me give you an example of what I mean... The intake and carb were FREE from a friend whose buying a crate motor for his 55 Chevy. How can you pass that up? I'm actually really please with the way the car performs. It's not choppy or rough in any way (except for idle of course) but otherwise purrs like a kitten and has a heck of a lot more power in it than I remember from the last time I drove it. It just acts as though it's always poised to take off screaming and with a loss of vacuum to my new disk brakes because of this damn cam it's really hard to hold this bad boy back!

Also... let me retry this... what I meant was... fun cruise car every now and then... not DAILY driver. Maybe 2 or 3 days out of the week to go on family drives and take to work to see people drool profusely. Again... If one of you guys wants to come down and give me a hand with the cam I'm all for it. Otherwise... there's not much more I can do. So I had a strong feeling the TC would help and that's something I CAN do, but I have no clue which one.

LET THIS BE A LESSON TO YOU SEMI-EXPERIENCED GUYS TRYING TO MOD TOO MUCH. Keep it stock... then when Joe at the local auto parts store asks you what you need you wont have to present a disertation on what components you put into what would have otherwise been a great car. You have no idea... one little mod can snowball into a massive chain of other mods to compensate for something not originally intended by the manufacturer. And all this for the sake of MORE POWER!!! ARH ARH ARH!!!! (Tim Allen eat your heart out)

Clues anyone? Anyone want to come on over and lend an EXPERIENCED hand? Doubt it... Am I the only one that lives in this horrible little town?

Please... someone... shoot me! Nah... I have kids to worry about... better yet... HELP!!!!!!!!!!!!!

Dario,
The best way to choose a torque converter is to decide on which manufacturer you want to purchase, then pick up the phone and call them and ask. Make sure and have as much information about your engine and car and let them tell you which one to use. There are too many variable involved to try and guess.

Excellent advice ! A good converter shop can buid you something that will work for you and be very streetable.Most will also stand behind a custom converter.

Excellent advice ! A good converter shop can buid you something that will work for you and be very streetable.Most will also stand behind a custom converter.


:yes:......a copy of my dyno sheet was sent to Coan in Kokamo,IN. and they built a custom converter to work with my engine. I am very impressed with the results!!!

David F.

Swaping the valley cover is a good idea to...yeag that way out of your league
AND flck that off, get a good used performer as suggested, change the cam
Chances are flicking off the inlet manifold will cover some of the costs to..
And yeah as suggested above keep the carb for now...manifold /cam will sort most, carb later if so wish.

FYI...

You might have 2.73 axle gear; it was listed as "standard" for 1967 210 hp 327 with powerglide. Perhaps 3.08 with a/c and 3.55 was listed as a performance option.

My 68 was originally 210 hp 327 with powerglide and 2.73 (the listed economy option was 2.56, 3.08 with a/c and 3.55 performance option).

The camshaft installed is a NHRA Super Stock class camshaft because it does not exceed the max lift rule as set by NHRA. It also has a narrow lobe separation angle, meaning you are experiencing its results, peaky torque curve, low idle vacuum because the valves are open together, thus a higher idle rpm is needed.

If the LSA was 110° to 114°, idle would be much smoother and alittle more streetable.
Solutions given are excellent, especially the ones to call a convertor manufacturer and put your faith into their suggestions.

Since you're on a limited buget, and who isn't, your best route in to buy a store brand convertor, such as: http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2D700333&N=700+4294908216+400304+4294865449+4294903957+115&autoview=sku
Remove trans, pull out old t/comv, change the seal in the oil pump, lube the seal, add a couple qts of oil into the new t/conv, install it, and reinstall the trans, fill up the trans, select all the gears, add oil if needed, and install an external oil cooler to help reduce the added temperature.

Yes, a looser convertor adds heat to the oil, so an external cooler should be installed. You have a PG, it has a smaller input shaft then a THM 350 or THM400. The only crutch is the trans. Torque convertors multiply torque. With the added power, the question is: "Will the PG slip in Drive?" So, trans might need an overhaul later. I had a 6-cyl/PG Camaro and trans worked fine. Installed a V8, stock 295HP 350CID, and PG slipped in Drive; 1st gear was fine.

Other suggestions given, new camshaft & lifters are good, another manifold, and higher numerical rear axle gears are good, but they cost more money than swapping out a t/conv.

But then, Snowball Effect comes to mind..........it gets bigger.........