I'm looking into a serious power bump for my 84 TA. Obviously the cheap HP jump is to go with a 350. Now I approached a local engine builder/machinist with the idea of building a 350-400HP 350 SBC. He said if I give him a short block (at least) he can build it up for me, carb, intake, etc. for 2 grand. Now that sounds in line with what I've heard.

I'm unsure if its cheaper to build the motor in the garage. I've looked around, it seems like if I order all the parts needed to get to that power output, it comes close to what it would be to have him do it. Also I have some parts that are supposedly interchangeable between the 305 and 350. Motor Mounts brackets, the HEI dizzy, the water pump among other things.

If I did build it in my garage, I'd probably go with the Performer intake, Vortec heads, a non computer controlled carb, and an LT4 hot or Lunati cam. with lifters etc included. All that stuff alone, I'm looking at possibly close to what he wants. The other thing is, whats involved in making a non computer controlled carb work with the ignition and all that stuff in the car?

I've toyed with the Pontiac 400 swap. But if I do that I might as well kiss my ten bolt goodbye before I even let the clutch out, and will need at least a T56 if not a Richmond 6 speed to handle the torque. (I want to keep my car a manual, and if I'm upgrading trannys I would rather get the extra gear.) And that is IF I EVEN FIND A 400. I might know where to look.

What would be my best bet? I'm leaning towards the 350 but I don't know if I want to build it in my garage or have the machinist build it.

 

What heads was he going to use?

+400ft/lbs vrs a T5 sounds like a good fight.. I know who I'm betting on.

Why ditch the ECM? If you have a L69 ECM that is great. Saves loads of cash and is up to the job.

 

I'm not sure what heads. I'll have to ask him. And yes, I know NWC T5 vs anything more than 300 ft lbs and spirited driving is a one sided affair. LOL bye bye third gear. I don't know what I'm doing about that quite yet, if I find an LT1 T56 I'll swap it.

So you're saying I could use the L69 carb, and ECM with a 350 and still not have any issues. Most of my emissions stuff is either broken, worn out, or just plain screwed. I wasn't sure how the L69 carb would run if you eliminated all the emissions equipment. If I can keep the L69 Q jet, and dizzy, all the better, saves me more money.

I guess if I could get a rundown on what I could keep from the L69 for the 350, I could give the guy all the parts. A long block would cost roughly the same amount. I can find a 350 longblock around here for less than 500 bucks easy and the idea is have it reconditioned and built up. What kind of cam would I need to run, I'd like it not to fall on its face and not require race fuel.

 

All you need is a 350 knock sensor.

Since you have a L69 ECM it has a more aggressive timing table suitable for performance where the LG4 has a table suitable for smog police getting groceries.

Keep the valve overlap low and the ECM can handle mixing fuel easy enough. To suggest a cam though people are going to need to know the whole combo all the way to the rear axle.

People over look the CCC setup often I'm a bit bias to it my self. The secondaries tune like a carb and the primaries tune like a bastard child of a carb and FI.

The '87 L69 ECM is hacked so you can tune your own chip if needed. You can find them easy for cheap on Ebay.

If you are going to invest that kind of money into a rebuild find your self a roller block to start with.

 

Actually its an 84 L69 ECM. All of the L69 stuff is 84 spec. I still have the cam, but you'd have to get it turned and out of the original block. The CCC Qjet I got so close to running right with the LG4 in there, but it wasn't quite there. The problem I had was I was throwing lights for too rich, and it would bog down and stumble hesitate etc. (Classic bogging symptoms if I'm right....) I'm open to using it if I can find someone who can tune that bastard right..... The final nail in the coffin for the LG4 was losing oil pressure til I had none. If you want a better rundown of what I have in mind for the car...

350 putting out approx 400 horses, NWC T5 (Temp most likely. I have all the parts to put it back in so....) if not that T5 then it will be either an LT1 style T56 or a Richmond 6 speed most likely, stock clutch, stock driveshaft driving the original stock 10 bolt 7.5 inch 3.73 posi rear. I've looked around about the 10 bolt, the argument is that if I'm not at the strip everyday the ten bolt should be just fine.

Suspension is going to be upgraded all around.

Could I use a 010 350 block (those seem to be dirt common) with a roller setup?

If not then I'll keep an eye out for a 87 or later 350 with the roller setup and if I'm lucky Vortec heads already on there. And it will just need a lil encouraging to get to the power numbers.

 

Yea I get that you have a 84 ECM. I am saying that you can buy one on Ebay from an 87 L69 and use that and it's tunable.

400hp is no joke a lot of people don't understand that it's a tall order. You are not going to throw parts together and get it unless you buy some really nice heads.

Vortec heads making that power probably need to be over cammed a bit and modified to handle the cam and valve train. It's going to have to spin over 6000RPM to make that power with those heads IMO. Hopefully someone who's found different can help. You said the "V" word you may actually get a discussion now.

One thing I do know for sure is your car will need to be upgraded all the way to the tail-pipe to meet your goal.

Zero oil pressure with a mechanical gauge or the factory? I know it's not the point of the thread but the factory oil sending unit is notoriously bad.

010 block is "ok" but it's time has well passed IMO. If you got one that runs good that's great use it. But I wouldn't invest good money into the bottom end. A 1pc rear roller is much better and easy to find. Money much better spent.

Making a 010 roller is costly and again silly IMO. It may be controversial but there are still guys that get all stary eyed over "4 bolt mains" and it's just buzz words from the passed at this point. Spend 2-3k building one to meet your goals when you could spend it on a roller, or better yet a LSx swap.

 

indeed, most notably that T5. I'll see what I can find. In realty I'm probably looking at 350-400. In that range. I have a couple friends, one with a 477 horse 406, and the other with a LS1 modded to 374 HP at the crank. Both cars do 13 second quarters with ease, and thats with the 406 car spinning the rears for the first 100 feet. I'd go with a 383 stroker, but I want to get a decent baseline starting point before I start doing that. As I said, the 400 Poncho was another idea, and naturally the LTx and LSx. I even thought about building an LT5 but that would have been overkill. Problem with the later motors is I'm not an electrical genius. So I've been trying to avoid those.

 

If you are still considering having someone build your engine, I have some advice. Check and see if the potential builder has completed builds on the road in your area, so that you can try and verify the performance level of the engine you may be getting.

The research you are doing by reading up and asking questions here is a definite advantage. There are so many parts for these engines, and with each individual having different preferences and ideas it is not always simple to get everything to work together. Asking for a 400 HP carbureted 350 is a tall enough order. The builder may be able to provide this. Then, you would just have to worry about connecting whatever dash gauges you want. If you wanted the engine to work with your factory Q-jet and ECM, however, things can become more complicated.

Learning as much as you can first and then assembling the engine yourself may be the best bet. If you don't have the time or tools available to you, then do as much as you can to figure out what combination you want and go to your builder with that.

The main point is that since this will be your engine, how it turns out most likely matters to you the most. If you have a reputable engine builder that you trust, then you can simply go to them with a HP goal in mind, and let them take care of the rest. Builders could have time commitments to meet however, other customers, certain specialties, food to put on the table etc. so if you feel confident it really may serve you best to take the time and figure out what components you want to use ahead of time.

 

You've pretty much nailed down what I'm trying to do. I'm trying to figure out what is the best combination of parts and etc for the engine. I'm certainly able to build the motor, just don't have every special tool in the book (crank thrust measurement dials etc, though I could use feeler gauges for that stuff as well as Plastigauge for rod clearance). My issue with going to an FI setup like an LT1, L98, LT4, is I'm not an electrical genius. Give me a diagram and I can wire a car, but if I'm custom wiring a car for a setup then it gets tricky. I'm open to the idea though. I suppose best case scenario I build a 383 LT1 stroker with an LT4 cam or an LT4 383 stroker and drop the thing in there with the T56 backing it.

My goals are to have a car that can run high 12s/low 13s, and still be able to carve canyons. In short a good all rounder. I know looking at the TTA power figures (real ones not the fake BS 250 one) that 350-400 HP can easily accomplish what I want. I'm not worried about the rear yet, it was totally rebuilt sometime in the 90s and it has less than 100K miles on it since then. I have nothing against using FI setups, just leery about wiring the car for it.

Now if someone can talk me through what needs to be done to wire the 84 dash and etc so I can use the LT1 then I might be able to do it without a problem. I really want my car to appear stock at first glance. Meaning it must look like it came off the factory floor, but to the sharp eye it will seem like something is not quite right about it.

If someone can help me nail down a setup to make 350-400 horses (I put down 400 in the title bec if you get 400 then obviously can make 350) then I can piece together the motor little by little or at least start gathering the necessary parts. This is a street car that I'm building, not a race car.

Thanks.

 

I should add, my stock ten bolt has a 3.73 posi gear set in it, so its certainly capable of pulling down the times, and a couple friends of mine, one with an 82 TA with a 406 and over 450 HP ran 13.2s all night long spinning the rears for the first 100 or so feet at least has no traction. the other has a 2002 Collectors Edition six speed with a lightly modded WS6 motor in it with 374 at the crank, he ran 13.4s all night long again, he had some traction issues too. So I know roughly the power goal I need. Somewhere between the TTA's true power output of 310 or so HP and 400. More likely shooting for 350-375 HP range.

 

Replacing the heads, cam, intake and exhaust manifolds may be enough to achieve your power goal, but I'm not sure of the tolerance/tunability of the ECM used with the computer controlled Quadrajet with more aggressive cams.

If you decide to go LT1, you will want the engine and transmission with all attached accessories, the ECM, complete engine/transmission wiring harness, and a fuel injection fuel pump. There will be some wiring to figure out, namely finding out which wires go to the fuel pump, ignition switch, cooling fan relay(s), and then the tachometer and air conditioning switch behind the dash. For an '84 car I believe you will need a converter box to get your cable-driven speedometer to work with the electronic speed signal from the transmission, or you can use an electronic/aftermarket speedometer. I know it is more work, but an LT1/T56 will be an upgrade over the 4 barrel 350 and 5 speed. With the car going on 30 years old, replacing some wiring might not be a bad idea.


Most of this has been covered extensively on these boards. These links should provide some help:

https://www.thirdgen.org/quadrajet
https://www.thirdgen.org/forums/carburetors/
https://www.thirdgen.org/forums/ltx-lsx/

 

I was going to do a T56 swap anyway, so the 5 speed will no doubt be removed from the drivetrain. My issue with a FI swap and LT1 wiring is, all the write ups I've found thus far have been for converting a FI car to LT1. I haven't found a writeup to keep my gauges for a carb car. Another issue that FI cars don't have is they already have an in tank fuel pump. I have a pump on the motor. So I'm already looking at swapping out a gas tank, possibly the lines for said gas tank, the motor, not to mention carb wiring to LT1 wiring. I'm trying to get the chassis squared away so I can move the car around at least if I need to. The reasoning behind the carb motor is I keep my guages no problem, and I'm not messing with the gas tank.

But like I said, if I find step by step with pics of everything for complete electronic dummies (I'm an electronic dummy I admit it), I'll look for an LT1 maybe stroke it. But as I said, I haven't been able to find an LT1 wiring conversion out of a carb harness.

 

I am also a fan of keeping things simple, achieving the goal with the least expense.

Something else to consider is if you create an ambitious project with many changes involved, your chances of having a disassembled vehicle sitting for an extended period of time go up.

I know there are some proponents of the factory computer controlled Quadrajet on these boards. Some searching should provide you with any answers you are looking for. Our cars are lighter which is an advantage, but it will take a pretty healthy 350 to run with newer LS1 cars.

 

well I'm also toying with the notion of building a stroker out of the 350. Chances are the block I use will need to be machined anyway. But, I have been digging around on the LT1 swap. Too much customizing and etc for my time and budget for now. So it will likely have the carb. The guy I was thinking of having build the motor knows his stuff (you tell him you want X HP or X ET and he gives you a motor that matches or better), but I was asking on here about combos because I could also build it in my garage. I found a couple combos in sigs that make a fun easy to drive 383 stroker for reasonable cost.

 

The CCC qjet ECM doesn't care how much HP you are making it's a reactive system and as long as you don't have too much positive valve overlap it can control mixture properly. So if you go aggressive with the cam use a computer or FI friendly profile.

The only problem is the LG4 flavor with its down right lazy timing.

 

Hmmm.... so you could use a Q jet with a stroker, that just doesn't seem right. But yes, the car was an L69 originally, that motor blew up big time. The LG4 was a free motor, but I ditched the LG4 dizzy and computer. Kept the L69 dizzy and computer. My guess is with the stroker I can keep the L69 HEI dizzy, even with a worked over 350 I could probably keep the dizzy. When I get that far I'll talk to the motor builder, I'm just digging around with ideas, and opinions. Here were some specs I found that appealed to me. Obviously I don't need to go forged if I get a powerhouse stroker kit. And I might use shorty headers, not sure yet.

383 motor specs
10:1 compression
73 010 2 bolt block with splayed caps
eagle forged h-beam rods
Eagle forged crank
JE forged pistons
Dart Pro 1 heads unported straight out of the box
225/230 .525 lift hyd/roller cam
750DP carb
RPM airgap intake manifold
Full length hedman headers

This combo reportedly runs mid to low 12s.

 

You would probably want to upgrade the ignition system but otherwise would be good with the L69's distributor.