I'm re-doing my rear end on my 84. The question I now face is wether or not to do the tranny too. It is still the stock 200-4r. I'm upgrading my rearend to a 7.5 posi that will have a 3.73 ratio (if all goes correctly). Will my tranny hold up to this, or is it time to just shell out for the TH 350?

Whats your engine specs?

H.O. Deluxe 350 complete crate. 625 cfm Holley, hooker shorties. I think the manual says 330 hp. I had x-piping put on for my exhaust and two flows.

If you have the money buy a built 2004r, it will make like better with the 3.73 on the highway. If not toss a 350 behind it, 330hp isn't really going to blow it up. I bought a Level 2 2004r from Bowtie Overdrives rated to 500hp, not making near 500 but I figure plan for the future. Cost me $1500 with 2400rpm stall, tv kickdown kit and shipping from CA to NY.

Ahh thanks. Well that price kinda hits where it hurts. I can get a sweet th350 streetfighter for $800 rated for 450 hp. So I'm thinkin it sounds better. Because I'm workin with a slightly more than limited budget. But thank you kindly.

Properly built a th2004r can handle 700 hp ----unless you are doing neutral drops it can live with 330 hp indefinitely even in stock form

hehe... I haven't dropped it out of neutral that many times... dang... after that statement I've decided 100% on the 350. I'm looking at a tci street fighter. supposedly shifts harder than the 200 r4. dang wow yea done way too many neutral drops in it for it to last. I knew what I was doing too but it was just so much fun though haha. especially to trench a yard... or two

If you do use a TH350 Trans you won't have overdrive. It will limit your highway cruise speed alot! I would if you plan on upgrading find a 700r4 in the junk yard and have it rebuilt with a decent shift kit. I have had all the worries of using the th350 trans with a set of 3.73 gears before and trust me you want that overdrive! My cruise speed at 2500 rpm was a crappy 65mph at best. If you use the 700r4 or even the 200r4 both of which have overdrive your cruise rpm would be around 2000 @ 70mph. I would build the 200r4 you have. It will hold up to alot more than you would think. Just make sure that the job is done right. I also am pretty sure you can find someone who can do it for alot less money. I knew a guy who would rebuild the 700R4 for 700 bucks with a stall convertor and corvette servos. Good luck!

If you do use a TH350 Trans you won't have overdrive. It will limit your highway cruise speed alot! I would if you plan on upgrading find a 700r4 in the junk yard and have it rebuilt with a decent shift kit. I have had all the worries of using the th350 trans with a set of 3.73 gears before and trust me you want that overdrive! My cruise speed at 2500 rpm was a crappy 65mph at best. If you use the 700r4 or even the 200r4 both of which have overdrive your cruise rpm would be around 2000 @ 70mph. I would build the 200r4 you have. It will hold up to alot more than you would think. Just make sure that the job is done right. I also am pretty sure you can find someone who can do it for alot less money. I knew a guy who would rebuild the 700R4 for 700 bucks with a stall convertor and corvette servos. Good luck!

Tahts the problem now with my 200 r4. Whenver I go out on the highway ill be doing 70 and it sounds like it needs to shift again but it wont. either the overdrive is screwed or something with the kickdown is cause when i step on it anywher after 50mph it wont kick it only keeps going. Now if I rebuild my 200 r4 can I get a kit on it?

yea you can get a shift kit and alot more the reason 200r4 is a cool trans is because it has a really low first gear :) 2.87 i believe. so it really launches nice. Use that trans and about a 2400 rpm stall convertor and it will run good. it sounds like your trans has something wrong with the throttle valve. your rpm should be pretty low. if you haven't installed the gears then you should be lookin at around 2500 rpm at 70 if the overdrive isn't working. with it working it will drop to around 2000 rpm or so.

dont neutral drop it lol especially to trench a yard you have more than enough hp to just step on it and burn em up :P

Oh i never neutral drop it anymore. I onyl did that when a brake stand wouldn't work back when I had my wittle bitty 305 in it. was pushin barelly 150 or so... So Can I get my 200 r4 rebuilt for $700 and have a shift kit in there? I'm assuming having it rebuilt would clear up any overdrive problem or that throtle valve problem?

YAY! I found a 700 r4 that came out of an 88 chevy van. it supposedly ran perfectly fine when it was taken out but that was 3 years ago. it was sitting on the floor of a friend's shop. I know I have to shorten the drive train 3" right? It wasn't my friend's tranny or else Id have gotten it for free but the guy wanteed to be rid of it so He sold it to me for $200. From what I looked around at that didn't seem like a bad deal. Worst case scenario is Ill have to pay for a rebuild right? Are there about to be any major crisies I can avoid that any of you know of from experience?

Lower gears are easier on trannys. IE 3.73 is easier on a tranny than 2.41.

Never neutral drop any trans.


The 2004r costs roughly the same to properly build as the 700r4 and some of the components are the same.


To put a 700r4 in an elky you need to shorten the driveshaft 3". You will also need the tailshaft housing for a B or D body car. It has a mount casting on it that places the mount in the same place as the 2004r.

I prefer the 1st gear ratio of the 700r4 over the 2004r. 2nd gear in both especially the 2004r could be lower though.


Your speedometer gears will have to work out to a 3:1 ratio if you are running 26" tires.

Lower gears are easier on trannys. IE 3.73 is easier on a tranny than 2.41.

Never neutral drop any trans.


The 2004r costs roughly the same to properly build as the 700r4 and some of the components are the same.


To put a 700r4 in an elky you need to shorten the driveshaft 3". You will also need the tailshaft housing for a B or D body car. It has a mount casting on it that places the mount in the same place as the 2004r.

I prefer the 1st gear ratio of the 700r4 over the 2004r. 2nd gear in both especially the 2004r could be lower though.


Your speedometer gears will have to work out to a 3:1 ratio if you are running 26" tires.

Lower gears are easier on trannys.

Yea the thing is... i feel like a jerk... this whole time... you can laugh in your chair there at home if you want as long as you dont openly make fun of me but well... this entire time i only had a th 200.................. yea i know... stupid me. I was under the impression mine came stock with a 200 r4... well i was wrong. so now i hope this explain a little more. sorry for wasteing your guys time.

No prob. Only 85 and later had 2004rs as an option.

Hopefully this post will go through... The server is obviously having major probs. Took 5 minutes of trying just to get this far and before that the site was down.

Yea the thing is... i feel like a jerk... this whole time... you can laugh in your chair there at home if you want as long as you dont openly make fun of me but well... this entire time i only had a th 200.................. yea i know... stupid me. I was under the impression mine came stock with a 200 r4... well i was wrong. so now i hope this explain a little more. sorry for wasteing your guys time.

Don't take it too personal, we've all made what we consider stupid mistakes. It's all part of growing up and gaining expererience. Now I know why you were saying going to a TH350 would be an upgrade though. There are many in here that have made worse mistakes though. I'd even bet that there is somebody in this world that bought all the parts to rebuild their engine, which they thought was a 350 because their freind said it looked like a 350 and found out it was a 267 when the pistons didn't fit.

Yea so I'm replacing the tranny with a 700 r4 and I'm trying to find a way to get a third member with posi so i can put a 3.73 in too. hopefully after that i'll be feeling a major difference in my take off. considering i dont have a ake off right now. its more like i roll for a second then suddenly acelerate haha.

The 3.73 will make a difference. Lower gears makes a vehicle feel allot lighter. Much less effort is required to get it moving.

I am about to put a 3.73 rear in my elky. (waiting on speedometer gears). I have a 7.5 one and an 8.5 one. I'm putting in the 7.5 right now. If I like the ratio I'll have a driveshaft made for the 8.5. If not I'll probably put 3.42s in the 8.5 first.


Right now it still has 2.41s. Acelleration from a stop and intermediate speeds is not very good. 3nd gear of the 2004r and 2.41s just doesn't let the engine get into it's powerband so it isn't quick but.... Acelleration at speeds above 50 is great. You can hit 80+ without even thinking about it. But I'd rather help out the low end as that's where you drive at.
On the freeway the 3.7s are going to be a little more than I want I think. After running the numbers I think 3.42 would be better but we'll see.

I thought about using 3.42's instead too. I have a set from an old camaro but I just really want a 3.73 back there instead. I thought abou thighway cruising too but I'm not really out on the freeway enough and hopefully the overdrive on this 700 r4 will help significantly. I also didn't want to waste that 3.08 first gear on the 700 r4. I hope to feel a very noticable difference going from a th200 with 2.14 in the back to a 700 r4 with 3.73 in the back.

It'll be a night and day difference.

I just pulled the elky into the garage so I can swap the rears. I'm putting the 3.73 rear in then I'll drive it around a little check it out then I will change the speedo gears and install a couple other parts in the tranny. I'm replacing the TV bushing and putting in a new TCC apply valve with a teflon seal. It's cheap insurance while I have the pan off.

I'll find out pretty soon if I like them or not.

Do tell of this experience aftwards please. Seeing as we have nearly identical cars I would like to know the actual feel of difference. It will be a week or two before I get mine in. i'm still waiting on parts to be shipped blah blah

I put it in yesterday. Have only done a test drive in it though. Gotta bleed the brakes again. Was nice on the quick trip but I think I may be looking at putting 3.42 gears in my 8.5 before I put it in though. Just a feeling

I put it in yesterday. Have only done a test drive in it though. Gotta bleed the brakes again. Was nice on the quick trip but I think I may be looking at putting 3.42 gears in my 8.5 before I put it in though. Just a feeling

I have a Monte Carlo SS with the 7.5 rear and a 3.73. Its not a problem on the freeway at all---I commonly drive at speeds up to 80 mph and the engine seems to be loafing. It has a 383 and a th700r4 with throttle body fuel injection and gets about 20 to a gallon depending on how heavy my foot is that day. As far as acceleration goes, its a hoot to drive, runs consistant 12:80s on street tires and closed exhaust. (full duals with headers and flowmasters)....Dan

So just checking again on what all I need to do. I have an apointemnt scheduled for my drivetrain to be shortened 3'' right?

I know there are topics on it but I want to clarify. The bracket mounts for a th200 will NOT match the 700 r4's right? Do I need to do some fabrication or are there adaptive brackets for this?

Also my tranny came with a tailshaft housing. I was told I would need a B or D body's tail shaft housing, and I was curious as to why?

Hopefully in the next day or two I put in my new 3rd member and 3.73's to get them worn in before I switch trannys.

Now last part on the checklist is a new torque converter.

3" is correct assuming a standard length 700r4.


The easiest way to mount it is if you have already had a 2004r... If you have the 2004r crossmsmber (which requires the additional bracket on the drivers side which 84 down doesn't have) you can use the tailshaft housing from a B/D body because it has a mounting flange on it already that is in the same place as the 2004r.

Now if you don't have the 2004r crossmember and frame bracket for it... I have heard people modifing the stock crossmember but I have not done it myself.



As for the 3.73. I put the speedo gears in and other parts and went for a drive. It pulls very well off the line. When doing a double downshift it really grabs once it's done doing it's shift. Also my TCC seems to be working properly all the sudden. Dunnow why but I'm not asking.

Oh gosh, I hope its not too hard to figure that out.

So there isn't going to be any comman ground going from a TH200 to a 700R4.

TCC? Is that a traction control or something? Did you add that on or is this something I should have too?

I have also been informed that shortening your driveshaft is a bonus for performance in some way. Unfortunetly this convesation was cut short so I wasn't able to get all the details. Does it increase torque? I thought I heard him say it just gives less to twist on the drivetrain. I'm not too sure.

I am going to look up the gear ratios of the TH200 and 700R4 as soon as I'm done sending this because I'm still curious as to what kind of performance increase I'm going to be getting.

Currently I have an HO Deluxe 350 it is supposed to push 330 hp. How much of that is getting to my wheels I don't know. My current transmission is a TH200 and my rear end is an open differential with a 2.14 gearing. Swapping to a 700R4, posi rear end with 3.73 gearing. My friend helping me says its going to be significant but not really awesomely different. Is this true? I really don't want this all to be a waste of time.

Actually the th700r4 mount is within 3/4 of an inch of where your transmission mount it now so just by elongating the mounting holes a bit both where the transmission mounts to the crossmember and where the crossmember mounts to the frame, you should be able to compensate fairly easily. also I believe the transmission is a little more than 3 inches longer---closer to 3 1/2 so that's how much you need to shorten the driveshaft..... As for the rear end, one from a Monte Carlo is a direct bolt in..the ones from the SS's were either 3.42 or 3.73 depending on the year and its a lot easier and usually cheaper to find an entire rear end to swap in rather than buying the parts individually and paying a professional to set them up---recommended--if you have never done it you can ruin a set of gears real quick...and your friend is so wrong its funny---its going to be like daylight and dark---you will not believe its the same car on acceleration and the overdrive will keep the cruise rpm near the same---the best of both worlds.... the 3.06 first gear ratio combined with a 3.73 rear would give you a 11.41 ratio so the rear tires are going to see 11.41 times the amount of torque the engine puts out and the .70 ratio for overdrive will make the 3.73 appear to be a 2.61 ---not to far from the 2.41 you have now. your current multiplication factor with the 2.48 first gear in the tranny and 2.41 rear gear is only 5.97 times the engine torque---now show that to your friend and inform him there is going to be close to twice the power to the rear wheels in first---even the second gear ratio of 1.62 times the rear ratio makes the overall ratio a 6.04 so second gear in the new setup will be slightly stronger acceleration than first in the current setup and third gear wiil have a more favorable ratio of 3.73 than the current second gear of 3.56---Oh by the way the TCC is the torque converter clutch---which eliminstes the "slip" in the torque converter by actually locking the engine to the transmission..Its electronically controlled by actuating a solenoid in the transmission.. you can make the circuit controlling it as simple or complex as you want to. A toggle switch can be wired in so you control it manually or you can use the pressure port on the valve body for forth gear to put a switch in and only allow lockup in forth gear. you can also add a vacuum switch in series so that it disengages on acceleration and another toggle switch can be added in series so it can be turned off completely is those situations where you don't want to risk burning it up----like at the drag races--thats how mine is wired----I hope this book helps....LOL...............Dan

Thank you very much. This was probably one of the most informative posts I've ever seen.

Unfortunetly the Monte Carlo rearend tip is a little belated. I purchased a 7.5 posi 3rd member and a 3.73 set about 2 weeks ago. It is ok because for a grand total of $100 I don't think I could have gone wrong on that. I'm probably not going to be putting these in myself after all. I do have a friend who is a "retired" mechanic of 60 years. He will surelly knwo what hes doing and has already offered to put in the gears.

The 700 r4 holes thing is a slight relief. I was afraid some heavy modification was going to be needed.

I'm really not worried about ever really getting my car tore up from drag racing. All I do is the occasional red light derby. There are no drag strips within 200 miles of me unless you count the local car clubs renting out a runway from the crop dusters every so often.

My th200 is slipping so abd now though that I have to floor it to get ir to go into reverse. My neighbors hate that at 6 in the mourning. I have no 3rd gear anymore and 2nd gear feels like its about to follow soon. I basically drive with it in 1 all the time and never go over 30... its depressing. The only thing holding me back from putting the tranny in right now is a torque converter and a center console.

Thank you finnaly too for reassuring me about the difference I'll be experiencing with this new setup. That was a crazy awesome book you wrote.

CLICK HERE FOR TRACK LOCATOR (http://chasinracin.com/track-locator/states/tx.shtml) This will hopefully help you find a track close to you. Red light racing is not only unlawful, but extremely dangerous. Run over some little kid that walks out between two cars and the last thing you'll ever see is the inside of Huntsville.

I really shouldnt have said red light sorry. My wittle town has only ummm 5? stop lights in it haha... sad i know. its more like... go out into the middle of nowhere and see who can get past 7 telephone poles, yea still dangerous but what isnt? Visibility isnt really an issue in case you were thinking about "oncoming traffic". first you have to have traffic in order for there to be oncoming traffic, second you can see the next township. its 11 miles away. Its whatt the city cops even told us to do because they didnt want us racing in town not only for safety reason but because it keeps evryone awake haha...

sorry its just how a small town operates.

This map only proves to me what I already knew. there is no drag strig within 200 miles.

I know its illegal to race anywhere outisde of them.

Amarillo's should be taken off because its no longer active.

Thank you though.

Movieboy8 I got a good laugh out of your post describing your town. I also grew up in a small town and thought your description of oncoming traffic was brilliantly put.