I'm thinking of fixing up my old beat-up 3rd gen. This car has always had a special place in my heart. Since I've had it as a 2nd car while I bought and sold 3 others. Went from a mint-condition marron paint and drivability to a 200k mile, drunk beat up (drunks hitting the car downtown Nashville) and Atlanta acid rain killing the paint, sit-around car. I'd like to change that next year.

Currently, just a 90 RS hardtop marron w/black int and 5.0L with 700R4 and 3.73s and arburn posi (stock 26 spline axles). Car still runs good, just using excessive oil badly (a quart every 2 or 3 tanks of gas). Could be the 100HP shot of nos I had on it 5/7 years ago... hehe

Anyhow, here are my thoughts. I won't be serious about this project until Feb or March or so of '03. But I like to make the plans first. I've already got my hands on a '74 400ci truck block that has built to 413ci and 500 miles on the engine. Ran 12.2s in the 1/4 all motor in an 81 camaro.

* 400ci Mouse Motor (either the used 413 or another built one)
* T56 from a 93/94 (the one with 0.50 overdrive), already found two of these too.
* '92 Z28 trim (ground effects, wing, hood), but I'd rather use a fiberglass hood.
* Sometype of complete suspension overhaul (I'm too use to the awesome Cobra handling).
* Complete new interior (has that 70s-old-car smell to it, been sitting for years)

Keep in mind, this will be a dialy driver and long-trip car.

My questions are about the fuel injection systems to use. I'm a Ford ASSET graduate, specializing in drivability, not only that but I program chips for Fords. Also did my RS chip 7 years ago myself (got to love binary). So I think I can handle the TPI and LT1s. Just I'd rather stay away form LT1-Edit and use a chip programmer to code my own for the TPI.

My options are:
* Aftermarket modified (runners and heavy porting) 87-92 TPI
* LT1 heads and LT1 intake/runners

I'd rather stay with a stock-looking setup under the hood. I know of the Holley fuel injector carb setup I wouldn't mind trying, but I like the looks of the TPI or LT1 setup. The Edelbrock multi-port injection is a nice option too. But I don't want to run a big air cleaner utop that. A nice honed-out TPI would work nicely I think, if it can handle it (see below).


Q: Can the TPI units be modified enough to flow enough for the 413ci SB with a 292 cam (yeah, big cam)? If so, what modifications are recommended? I.e., high-flow runners, larger TB, ported lower intake, etc? I know I'll have to switch to the center-bolt heads (with the 45 degree center intake bolts). Was thinking of some aftermarket Dart or alike heads. The coolant passages are different a little as well on the 400. I've heard of people taking normal 350 heads and drilling/modifying them for the 400 block. Didn't know if this was just as easy on a set of aftermarket aluminum heads for the newer centerbolt valve covers and TPI lower intake.

Q: If I decide to go with an LT1 route (most likely not, as I don't want to pay for the LT1-Edit software), what all is involved with the reverse coolant setup of the normal LT1 block and the older 400 block to get the heads to work? Or is it even possible (put LT1 heads/intake on an old-style 400ci)?


Thanks in advance! I'll try searching around the forums a bit more, but I've really found anything to answer my questions though.

I'd like this car to give my friend's car a run for his money, '01 Firehawk, highly ported CNC match heads, milled to 11.5:1 compression overall, LS6 intake, long tubes, no cats, 3" exhaust. He pulls my friend's C5 vette with just a 100shot of NOS. The C5 w/NOS dynos 402 to the wheels. So my friend's Firehawk should be a bit over 400rwhp.

Humm, maybe I should just swap in an LS1... Nah, shouldn't a 400ci with worked heads and a high flow TPI system out do that? Maybe I should be looking at an LT1 setup?



Eric

 

Oh, forgot to ask what type of suspension packages people recommend for these 3rd gens? I want sometype of touring suspension. Nothing too firm, but something better then stock. Are there some tubular k members/subframes for these cars? Adjustable coil overs?

And has there been any hydrolic brake booster conversions? The 96-up GT and Cobras went this route and I really like it. Since the last GM SB I built up would barely stop (292 cam in a forged 305 motor), no vacuum for the brake booster under hard accells then hard brake.

Thanks,
Eric

 

Hey man, I can't be too much help to ya, but go to www.thirdgen.org.


All the info you need

 

How about a heads, cam LT1/T65 with some juce. Very streetable, good milage, and should have no problem with the Hawk. Especially since your thinking of LT1 heads and intake already.

 

A heads/cam package on an LT1 is only the marginal performance I'd expect from the swap. I know the power those makes, me wants me.

Thinking all weekend, I'm leaning more towards a 400ci block, lightly bored (so it can be removed and freshened up with rings again 50 to 100k miles from now). A set of Brodix or Dart 220cfm heads with the 45 (or was it 23?) degree angle intake bolts for newer style intakes (lightly polishing, don't need porting flowing that much, but they will both port to over 300cfm! Holy crap!).

A nice 292 dur. cam in the 400 is a nice combo from my experience.

The intake system I am leaning towards an LT1 intake. But this where I am unsure if they will bolt to older-style 23 degree heads (i.e., centerbolt heads for a 400ci with 23 angel bolts with an LT1 lower? Possible?).

Found where one of the 3rd gen swap sites sales LT1 wiring harnesses. Just have to decide on a MAF or MAP setup. Would prefer MAF as I like the drivability and adaptive control that gives me driving through the mountains or over large climates. Just I hate to buy LT1 Edit... Oh well.

The MAP setup (93 only LT1s) has a reprogramable EPROM that I don't have to use the LT1 Edit on. But the MAF (94-95) cpus must be reprogrammed, no chip. I kind of like this approach as I am constantly changing my tune in my cobra with my laptop. The idea of pulling an EPROM and carrying an EPROM programmer with me to edit a slight thing annoys me.

Anyhow, any comments on the basic setup?

400ci 4 bolt, forged internals (rods strong enough for a 6500rpm redline)
Brodix/World/Dart 23 degree aluminum heads
10.5 to 11.5:1 comp. from combo above
LT1 intake assembly (will it bolt to a TPI setup/head, my basic question?)
Standard cooling (not the reverse flow)

Of course, this means larger injectors, custom MAF, fuel line upgrade (and pump), radiator upgrade, etc etc. The normal high HP swap out stuff from an RS 5.0L car.

I'm really getting excited over this project. Thing is, I have to finish my Cobra first (won't be until Dec to finish that).


And yes, it will get a little juice down the road. But that's the point of builting a strong bottom end, no need for most cars on the road. Would like to turbo it one day as I like to do custom turbo installs, but not at 10.5:1 comp. That's another year (ahh, what dreams may come).

And btw, my friend's hawk has a large cam (forgot to mention that with the other stuff) and a 125hp dry shot (42lb/hr injectors, custom tune). That's ontop of the over 410/420rwhp he's already making, stock pistons/rods/crank. That's why I want to build up this 400 with some serious heads and cam and intake to stay near him on the spray.


Thanks!
Eric

 

OK I tried to cut as much as possible to help reading out a bit. First off the LT1 heads will not work because they are reverse flow heads so you are going to need something else. You will still be able to mate up the LT1 intake to it but you will need to grind the center bolt holes to fit the pre 87 block, I would just get a set of really nice flowing aluminum heads for your motor (AFR or the like). The LT1 is a great design it will be really nice on the high end with the 292 cam but then again if the LSA is anything less than 112 you are going to run into vaccum issues.

You can modify the TPI to be able to support the 4XX block but you will need to do some major porting on the lower intake as well as getting a set of aftermarket runners like SLP or the like. You can go with something like the Mini-Ram or the Superram but to keep the stock look under the hood the mini-ram is the closest you are going to get. You are going to be needing some large injectors, bear minimum of 30#ers.

Suspension is up for grabs. Some LCA's with brackets, Eibach Proline springs, Adj Panhard rod, subframe connectors S&W racecars makes some really nice ones that connect in the middle, adj torque arm, IROC-Z wonderbar is a small but nice touch. Now as far as companies go Sphon, BMR, Lakewood, Hotchkis, are all that make nice stuff.

Hopefully that helps out a little bit. Good luck with your project sounds like fun.

 

Thanks Drkhrse89. That's the majority of the info I was looking for!

Yeah, I've pretty much decided on the LT1 intake setup (and harness and cpu) after looking at my friend's this weekend (all apart at the moment).

What's interesting is the LT1 lower intake seems to be a D like shape, and I think they call the runners in the LT1 heads "D" design.

Nothing that a good bit of porting looks like it will correct.

Thanks!
Eric

 

Thats right you do some porting and you will be looking at quite a sick motor. Keep us updated on the progress.

 

A little I am... Don't know if that is a sarcastic remark (sick as in, "you change from those D shape designs and it won't run worth a crap"), or if that was a compliment.

I won't be using LT1 heads, just the indunction system (which is what I was talking about porting to match the heads ). The heads I'mk looking at are either some Brodix or World Products. Some GM Performance Parts heads look very promising as well. The Brodix/World ones I am looking at fit the 400ci block, and have the 23 degree angled ports. So hopefully it's just a matter of porting of the intake... *crossing fingers*

Will be several months before even getting around to this. Who knows by then what I'll be building. But I have a good brain storm now.

Thanks!
Eric

 

The 400 is the way to go, use that block with some 5.7 rods and a decent crank and it should be good for a 150 shot.

The only thing I see wrong with your combo is the intake and computer. Your car is an RS so I'm assuming it has TBI on it now. You will have to change the wiring harness also, and the computer unless you want to stay TBI.

Since you have to swap harnesses anyway, look for a used DFI system, or 730 speed density ecm and harness. The maf 165 computer will work also, but the maf sensor makes it less attractive on the TPI cars. I'm running into problems now with it, and will have them sorted out soon. The LT1 ecm would be the way to go, but you'd need the LT1 edit and tunercat software to dial it in.

The LT1 intake can be matched to any head and bolt pattern. You could also get a single plane intake with fuel rails and throttle body to work even better, but don't know about price, unless you find it used.

Pro action makes some affordable good flowing heads, as well as the dart iron eagles. I would try to find something used, then get them ported, but that's me.

 

OneFastGta,

Thanks again for the info! I'm actually looking for a good strong N/A combo, no NOS for a while (will be shooting for 11:1 compression).

Yes, the wiring/computer/etc will all be junked. The car will go through a complete restroration. New interior, door and window seals, '92 Z28 hood & spoiler (debating on leaving the stock RS spoiler, but usability at 150 to 170mph, the Z28 spoiler looks to do nothing for downforce), 91/92 fined ground effects.

That's all exterior and interior.

The engine bay will be completely stripped (including engine, fuel, and brake lines, even the brake booster removed) and cleaned up. Cleaned up as in welding plates intot he open hole areas of the fenders and repainting to a fresh coat.

During the "rip everything out" process, the LT1 system will get a new wiring harness (found a 3rd site, can't remember name off hand that has em) for either the MAP or MAF setup I plan to use at the time. Will most likely stay MAF. I don't want a speed density or DFI setup as I want this to be an excellent daily driver. From Nashville to the Smokey Mountains, to FL and the Keys, to NYC. I don't want to have to pull over ever 150 or 300 miles when the climate changes so much to re-program the DFI. Blah.. hehehe

Besides, the LT1 wiring harness wasn't that much.

Oh, here's something I've always wanted to do. Don't know if people ahve already tried.

I wanted to replace the tachometer with one from a 90-92 V6. Just the face plate, not the actual electronics. My stock one goes to 7k, just like the V6 models. My RS has a range to 4500, where it is yellow to 5000. The V6 models has a range to 5500 where it goes yellow until 6000. This will be more like my RPM range with the 400 and cam (actually 6500).

Also, replacing the speedo with one from a 91-92 Z28. Now this could be tricky because my ranges a half circle to 110mph (115 is a dash past that). The 92 Z28 ranges a half circle to 140 (145 is a dash after that) if i remember.

Has anyone swapped the speedo on these cars? It is a simple remove and replace?

Thanks,
Eric