Will I have to put subframe connectors in my 90 RS to put a 450+ horsepower 500+ ft. lb torque 400c.i small block . Also how long wil the stock 700r4 stand up to that power. Already have new rear end for when the stock on spits its gears. Is there any thing else i will need?

Sub frame connectors should be the first mod anyone does to an F body.

That rear end will break in no time........1st hard lauch......

You will need more then subframe connectors to get that kind of power to the ground.......

The stock 700r4 wont live long behind that engine either. As long as you dont run slicks the rearend will last awhile. It all depends on the condition thier in now. That kinda power will find thier weak spots fast. Subframe connectors are a must and the very least you should do with that kinda power.

Shifty is right. When I put in my subframe connectors it made an enourmous difference, escpecially since I have t tops.

450hp on a stock drivetrain?

thats already a no no.

first thing i see is jam on the gas and the person your racing is already gone cause you cant hook.

The rear end, if you did hook would shatter. IT'll sound like throwing a steel bar at a train. a big ole mess.

Then if that rear end does hook and holds the weight, your tranny is the stress holder then. First thing i see going would be your internals very fast. Besides planetaries, there arn't many hard parts inside a 700r4 that would shatter from under 500hp. the planetaries are actually quite strong in 700's. But your bands will slip and give a lot more wear. Your clutches will burn, and autos dont like burnt clutches. And your torque converter, Having the stock TC with that much power makes it even harder on that TC.

all in all, thats a disaster waiting to happen.

I'd hold out on a huge power engine until i got my tranny fixed. the likelyness you'll hook are slim to none, but with a engine spinning fast and the car not going relative to engine RPM(becuase its a fluid clutch) makes it especially hard on the stock friction internals. Before you know it, you'll stop at a stop light and smell something weird. Like burnt brakes dipped into water. Its no fun.

Once your tranny can hold the mess, make sure your chassis can. SFC's are a must. Rear end support mounts should be replaced. LCa's even maybe.

Next would be your rear end. Now 10 bolts by definition cant take 450hp from a dead hook, no way never. They will shatter due to no support on the pinion end well there is support but minumal the whole case bends). Either get a aftermarket 12 bolt, or a stock 9" with custom backets for your thirdgen. 12 bolts can hold ~600hp, and stock 9" around 600 as well. where the 9" goes abiove and beyond the rest is when the 9" gets a good case and support materials.

Once you dead hook you put even more stain on the chassis, a new torque arm is a new must. suspension parts are a defiante to unibody cars.


Have fun, make sure you play safe. I'm pretty sure SFI requires cars with 450rwhp to have roll cages as well, so...

My car hooked up well enough to run 12.2's at 111.85 on 275/50/15 Radials with no suspension or chassis mods.

The rearend will hold up fine if you are running street tires and the automatic.

I wouldn't get discouraged, build the motor and drop it in, just don't run a sticky tire if you are worried about transmission/rearend breakage.

My buddy's rear held up fine also. He built up a nasty 400 sbc and was running high 11's on street tires and had no problem for probably a 2 years. Eventually he snapped some teeth off the ring gear. He did a gear swap and is still running same rear and running strong.

Bill

what suspension components did ur budy have on his car?

You'll definetely want subframes for multiple reasons. But since you are swapping engines, wait until right after you do the swap to account for any weight difference.

all he had was subframes connectors and koni adjustable shock all the way around.

Bill

Thanks for all ur input i wil have to try a few of youre sugestions

Yeah no problem man. Good luck with you project.

r90 how is your car doing? I remember a while back you shattered a clutch or something and then had some engine problems. Did you ever get your new engine put in? Any numbers or dynos yet? Just curious

weber, I ended up using my old car as a parts car and picked up the '91. The bottom end of the engine is done and will definetely hold some power, the top end will consist a lunati hyd roller cam, rpm air gap, and the protopline vortec heads. A commander 950 4bbl tbi is going to feed this and tune via wide band.

The overall process is going slow, namely because I picked up the z-28 as well. Also, ACS ripped me off $600+ took my money but never sent me the headers But I hope to have the engine and tranny in the end of this month and hopefully have some numbers sometime in aug. Fortuantly, the Z28 has a moser 9" in it, so I will probably swap that in the rs when I do take it to the track. That way I can throw the slicks on her. The goal is 11.5's n/a and a 10 sec pass on spray

r90,

That is awesome. So you are going to stick with the 4 barrel throttle body? Why not upgrade to the mpfi that holley has? Just wondering that would be awesome times if you could pull a 11.5 that would be pretty awesome.

Bill

Oh yeah who is doing your chip tuning? Are you taking that on yourself now?

Brian at tbichips.com did all of my tuning on the previous 383 setup I was running with the holley 2bbl tbi w/ 85pph injectors. He was great to work with, and did a very impressive job. If you have any questions regarding him, feel free to pm me.

This time around, I will be running the commander 950 ecm. There are a few reasons for this.
1) simplicity. The TPIS tuned port setup on my z is enough multiport for me! TBI is much, much more user friendly.
2) It will support up to 600hp, and give me various intake and nitrous options.
3) The commander 950 is capable of wide band 02 input as well as progressive linkage.
4) last but not least, price.

I like the multiport benefits, but I get along much better with tbi. It is all personal preference though

That is cool.

I have been toying with the idea of an aftermarket fuel system also. I just don't know which one to go with. I have looked at the projection stuff and also have been looking at the edelbrock pro flo setup.

It seems that either way I will be able to do the tuning via a laptop with the projection and with the little hand held thing that comes with the edelbrock system.

Are you planning on doing the tuning your self with the projection setup? If so do you have any exp diong that? Have you heard whether it is simple or not. I have heard that it is fairly simple.

Right now I am working with Brian and he seems pretty awesome. I have just got my first chip from him and am going to start data logging and making some more mods. I really would like to learn how to tune the setup myself but I don't think that I posses the patience.

Later bro

Bill

I am glad to hear you are working with brian and that it is going well. You are definetely in good hands As far as after market systems go, I really like what I am hearing about the holley commander 950. Most people say that it is pretty simple to use and I think that wide band is going to make it a ton easier on top of that. The only complaints seem to be that it just doesn't allow you to do as many things as say even a stock ecm will. However, the use of progressive linkage and wide band w/ the commander 950 has tons of benefits in itself.

I am definetely going to be doing the tuning myself for a few reasons. The main one being that the commander is set up for it. But also time. Since this is a project car, I can take time to learn the system, however still have the ability to do quick last minute changes at the track.

My z-28 on the other hand still has the stock ecm (7747) with a "custom" ed wright chip. Do not worry, I did not pay for that pos chip, it came with the car. However, I do want to go with a prominator, but want to doa little more research. I know a couple of members here have converted there 8746 ecms to a newer pcm, I would like to do the same, but not sure if it has been done with tuned port apps.

That is cool. I am wanting to do the tuning on my own car also. I hate to have to outsource crap to other people. I have always done all my own work on my cars and i look at it like why should chip tuning be any different. lol. I think i might just take the time and learn how to do it. I mean I can keep my car on the road with the right chip.

Let me know your progress man.

Later Bill

I will throw my two cents in. My 406 ran a 7.82 in the 1/8 with a 1.84 60ft on pepboy radial tires w/ no subframes, LCA's or relocation brackets. The tranny was rebuilt by a local shop and I had a 9.5 ACT 2800 stall in it. When I launched it I could feel the car flex. I tried launching the car harder but it started doing the mexican hat dance and wheel hopped so bad the rear view mirrow came off hitting me in the head almost making me crash. I never got the car back to the track after I put SFC's, LCA's and relocation brackets on it, but the car did feel a lot stiffer. If the car would have ever dead hooked I am sure it would have blown the driveshaft and/or the rearend eventually. I still think it would have ran 7.4's with some ET streets and the suspension work.