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 Rear gear for 68 Lemans 400 M21 long
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Scott J
Buffalo

USA
61 Posts

Posted - 11 Jun 2016 :  4:03:32 PM  Show Profile  Reply with Quote
Standard old school build. 10ish:1 TRW forged slugs, arp where it matters, unported #62's, Comp 292H ( yes I know ), Comp 1.5 magnum rockers , 1 3/4 Super Comps, RPM intake, no gasket or port matching, Holley 750DP(31 squirters) Pertronix loaded HEI( coil, pick up, GM module. Excellent state of time for its sheer lumpiness. This engine I didn't build but I've gotten it to run to really well and it's time for gears.

With an M21 and a 3:31 12 bolt I've got really poor torque multiplication. Car was an TH400 automatic but that blew so I converted the car to 4 speed. Now I can cruise and if I dump the clutch at high rpm it will burn out as long as you want but the top end of this car is way too much and it's sluggish down low even with a 215 65 15. I could make up some with cam but I'll save that for another engine.

I want a real nasty head snapper. Ive been following pure stock closely and like the whole purist vibe.

3:90, 4.10, 4.30? Please, if you've owned this type of set up I would be appreciate of your time!!

Thanks in advance!

Scott


Phil
The Great White Buffalo

USA
7215 Posts

Posted - 11 Jun 2016 :  10:31:09 PM  Show Profile  Reply with Quote
Scott, can you ditch the 2.20 first gear as well as the second gear and swap in gears from an M-20?

If not, autogear or similar may have an even better option regarding Muncie gears instead of changing your R&P and sacrificing highway cruising.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Scott J
Buffalo

USA
61 Posts

Posted - 11 Jun 2016 :  11:11:25 PM  Show Profile  Reply with Quote
Hi Phil!

Thanks!

. I was actually going to change the cam and do an M20 but the engine's dialed so nice now and I'd like to try the gear with the M21....

As well as reducing this thing's top speed....which right now, is somwhere well past my comfort zone in the car.

Part of me is curious to try the 3.90 over the others but the cam is soft low so I hope it's enough. I could wring 60mph out of first now the way it is. If I do end up changing the cam I'll probably go with a more modern milder grind and still have a really quick feeling car.
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Scott J
Buffalo

USA
61 Posts

Posted - 28 Jun 2016 :  5:28:41 PM  Show Profile  Reply with Quote
Went with an Eaton 4 series carries, moser axles and 4.11's. This should be fun.
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GtoGuy32
Cochise

USA
842 Posts

Posted - 28 Jun 2016 :  10:13:43 PM  Show Profile  Reply with Quote
Good choice.

Its a lot of gear for the street, but get some good tires and you'll be fine.

I run 3.90s with a 2.56 first gear and the torque multiplication is more than your setup and I LOVE it.

A lot of guys will claim you went with too much gear with a Pontiac engine. I don't think so, especially if you ever decide to get the car on a track.

Have fun with it...

https://www.youtube.com/watch?v=__cXG30BwAs

-Dave
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Scott J
Buffalo

USA
61 Posts

Posted - 29 Jun 2016 :  10:38:04 AM  Show Profile  Reply with Quote
Nice!!!! Yeah, that's some nasty power! Kind of looks lke the road we cruise.

It will never see past 6K and it's just broken in. We have nothing but hill and 50 mph speed limits. Someday I'll put a 6 speed in when I grow up. LOL!

Edited by - Scott J on 29 Jun 2016 10:47:39 AM
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Scott J
Buffalo

USA
61 Posts

Posted - 06 Jul 2016 :  11:14:11 PM  Show Profile  Reply with Quote
12 bolt rebuild with 4.11's done.

The car is now really in sync. 500 mile break in before I can pound it but it drives really well.

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GtoGuy32
Cochise

USA
842 Posts

Posted - 06 Jul 2016 :  11:53:09 PM  Show Profile  Reply with Quote
Scott, that is awesome. You'll have fun with that.

Long trips won't be great, but you already know that.

Enjoy.
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Scott J
Buffalo

USA
61 Posts

Posted - 07 Jul 2016 :  07:23:00 AM  Show Profile  Reply with Quote
Thanks Dave!

Yes, long 70 mph plus cruising will be all 2016 WRX now LOL

I could be happier at 50-55 and under though. It's really just "together".
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DanM
Buffalo

80 Posts

Posted - 21 Dec 2016 :  5:19:04 PM  Show Profile  Reply with Quote
I could barely stand the my 3.23 on the road. 3.90 would be intolerable. I suppose you might have no interest in ever driving 100 miles round-trip to the beach and certainly not going for any Sunday cruises.

But you could upgrade to a 200-4R. The over drive will solve all your problems. the 4 speed manual doesn't have over-drive so it doesn't do anything for you. In fact it doesn't serve much purpose in my opinion unless you are racing on a track and want to keep your engine in a narrow rpm range. 1st gear is about 2.5 and drive is 1:1. a TH400 low gear is about 2.5 also and drive is 1:1 so you don't gain any low end torque or highway rpm with an M-20. Meanwhile a 200-4R low gear is about 2.5 but you get a 0.66 OD. That's the best solution in my opinion.

I have this setup in my Lemans and can vouch for it. You can get hardened parts for the 200-4R that will handle any engine you put in front of it.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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RonW
Buffalo

44 Posts

Posted - 21 Dec 2016 :  8:03:00 PM  Show Profile  Reply with Quote
Hi Dan,
I have a 67 LeMans with a 400ci, TH400 trans and a 12 bolt 3.73 sure trac. I'm planning at some point to put a 200R4 in mine also.
Can you offer any info on what carb you have and how you set up the TV cable?
Thanks, Ron
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Phil
The Great White Buffalo

USA
7215 Posts

Posted - 21 Dec 2016 :  9:41:46 PM  Show Profile  Reply with Quote
Ron, I love the 200-4R and have done quite a few of them over the years with Qjets, Holleys, Carters and even one or two E-carbs. I make my own brackets because nothing was available in the 80's when I started retrofitting 200-4R's into older cars. But these days brackets are abundant for most carbs to make things easy for most folks. I still make my own brackets though. Easy to set up the TV cable with a little attention to detail.

Still have those transmissions in a couple of my old Pontiacs and earlier this year replaced the 400 in the Formula with a 462/KRE head, HR engine. Trans has continued to perform flawlessly.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 21 Dec 2016 9:42:40 PM
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RonW
Buffalo

44 Posts

Posted - 21 Dec 2016 :  11:01:45 PM  Show Profile  Reply with Quote
Hi Phil,
I have a Q-Jet built by Cliff Ruggles a few years ago. I recently picked up a Q-Jet off an 85 Monte Carlo (200-4R trans car) thinking I could swap the base plate and have the proper linkage?
I haven't had a chance to really compare the base plate from the Cliff-jet to the Monte Carlo carb, but I think I noticed the MC carb has 3 screws and the Cliff jet has only 2 in the base plate.
The 200-4R is a ways off yet, but definitely in my future.
Had one in a 70 El Camino 350s/b with 3.73 gears and loved it.
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67drake
Sitting Duck

Azerbaijan
1501 Posts

Posted - 22 Dec 2016 :  09:20:07 AM  Show Profile  Reply with Quote
Ron,base plates vary on the Q-jets over the years,so you can't always put a "newer" base plate on an older Q-jet.
If you're worried about the bracket that holds the trans cable on the intake,as Phil said,you can make,or buy most of them.
If you're worried about the trans cable or throttle hook up to the carb, I would look at Lokar.or call Summit.
You COULD change out the primary throttle shaft/arm from the old Cliff carb and replace it with the new shaft from the '85 Monte's,from what I know,but that seems like a lot of work when aftermarket parts are available.

I'm taking a '73 Pontiac Q-jet and building it for my sons '91 Silverado right now (4L60 transmission). I told him ahead of time he would have to look through my odds and ends drawer for the proper cable hook up to the '73 carb,or we'd have to order one.


71' GTO Original 400 M20 3.23 posi
13.95@102.1 MPH on street tires
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DanM
Buffalo

80 Posts

Posted - 22 Dec 2016 :  5:35:07 PM  Show Profile  Reply with Quote
RonW,

I have a Q-jet. The TV cable bracket came as an adapter kit from the Florida based fly by night shop I bought the 200-4R from. The kit had a bracket which I bolted to the throttle-cable-bracket using an existing hole in the throttle-cable-bracket. If you're halfway mechanical which I assume you are you will be able to see how two nicely located small bolts and maybe an extra hole drilled with a cordless drill will suffice. If you don't want to work with the nutty Florida guys you could buy a TV cable bracket from one of the usual aftermarket shops like Ames. Hacksaw most of the bracket off and just bolt a flat portion of the TV bracket to a flat portion of the throttle-bracket by overlapping them just enough to make space for the two tiny bolts.

The tricky part was getting an attachment point for the TV cable end. The plastic clip? at the end of the TV cable will snap onto a machine screw of just the right size. A counter-sink machine screw seems to work best. (Go to your favorite HW store and try a few). That machine screw can be attached to the bottom of throttle bracket using jam nuts. A stock Q-jet has a spare hole that works perfectly. When it is in place, the machine screw will stick out from the throttle bracket and be parallel with the throttle shaft but offset by about an inch and a half from the throttle shaft.

Properly, the clip is meant to clip onto a "post" that is shaped sort of like an allen head screw if you were to grind off half the head so the head is just the right thickness. The trick is getting the diameter of the head big enough for the clip to snap on, not fall off, and still allow just a teensy bit of play for it to rotate.

Meanwhile, as the throttle cable is pulled toward the firewall, the TV cable needs to be pulled away from the firewall. this means the bracket on the Q-jet will be such that the throttle connects to the bracket at a spot above the throttle-shaft-rotation-center while the TV cable connects below the throttle-shaft-rotation-center. As I said above a stock Q-jet is coincidentally built with a perfectly shaped bracket with holes exactly where you need them. I don't know why because there was no TV cable when the Q-jet was designed and there wasn't anything on the car to connect to that hole at that location.

Now, I have a friend with a Bridgeport mill so he machined a piece of brass that snapped into the TV cable connector and also was exactly long enough so that the TV cable was perfectly in parallel with the throttle cable. That way the TV cable slid in and out without dragging against the plastic housing of the TV cable itself. He put a tapped hole in the end of the post for me to screw into. I then screwed (outwards) through the Q-jet bracket into the brass post. Total overkill. Little brass post probably worth hundreds of dollars in engineering man-hours. But that's how we roll.

A picture would be worth a thousand words. No picture sorry. So I typed a thousand words.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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DanM
Buffalo

80 Posts

Posted - 22 Dec 2016 :  5:39:08 PM  Show Profile  Reply with Quote
When the TV cable is adjusted properly there will be just a tad bit of tension on the cable when the car sits there. When it's full throttle the cable will be about as far out as it can go.

The magic of the Q-jet bracket that just by happenstance works perfectly is that the throttle cable doesn't go in and out the same length as the TV cable goes in and out. This is like two kids on a teeter-totter with one of them sitting closer to the pivot point. The Q-jet bracket is such that one hole is further from the throttle shaft than the other by exactly the amount it needs to be to work the TV cable.

Spooky.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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RonW
Buffalo

44 Posts

Posted - 22 Dec 2016 :  10:55:28 PM  Show Profile  Reply with Quote
Thanks guy's, I appreciate everyone's info.
My Q-jet is actually a 1975 Buick carb that I had Cliff build for me.
I haven't been able to find any aftermarket TV kits for this carb, but I did find a website that shows the "required" correct geometry for the TV cable hook-up position.
I bought the Monte carb off ebay awhile back intending to just use the throttle shaft with the TV hook-up. I got the idea later to switch the base plates, but again I haven't really looked at it carefully.
I also think Cliff probably modified the base plate in my Buick carb, so that will be something to check also.
I've yet to put the carb it into service, but I've had the 200-4R planned for a long time, lots of other thing to do first.
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DanM
Buffalo

80 Posts

Posted - 23 Dec 2016 :  09:06:23 AM  Show Profile  Reply with Quote
I have a half dozen photos I took last evening but I can't figure out how to post them. I will be happy to email them.

Dan

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