Well, i recently bought my first truck, a 1987 C20 Silverado with a non-running 350 in it. A friend of mine knew i was looking for a motor and found me a small block 400 for $400. Anyways I'm not completely new to motor work/swaps, but I've never taken on a project myself. I'm wondering if using the TBI that is on the 350 now is an option? If so will I need new injectors, high psi fuel pump etc? How should i go about the swap. I have not removed either motor from the vehicle its in. The 400 is in a 1978 chevy tow truck. Any input would be appreciated, i do have some friends that are willing to help me if i need it but i would like to do as much of it as i can by myself. Hopefully i will come up with a cool truck.  

This is doable with some extra cost and effort, only you can determine the value of it for you.

The TBI uses a different intake bolt pattern than the older 400 heads. There's a couple ways to go, one is to modify the center bolts on the TBI intake to match the angle of the 400 heads. The other is to use the 350 TBI heads. To fasten these to a 400 block you need to add 6 cooling holes to each head, easily done with a hand electric drill motor and bit. You'll also need 400 head gaskets with this.

The TBI's computer will need a custom chip to recognize the additional 50 inches.

http://www.fastchip.com/

http://www.hypertech-inc.com/

http://www.superchips.com/

http://www.kcspeed.com/

http://www.jetchip.com/

The rest of the system you have in the 87 Silverado.

Issues you should ponder are the CFM capacity of the TBI on a 400 engine, the 350 3ngine's TBI only flows 400 CFM  and the 400 inch engine could use more so a TBI off a 454 or a Holley 502-6 at 670 CFM, or having Turbo City bore your existing throttle body to 2 inches would be a big help. This needs to be done before the chip gets made, as it needs to have all mods incorporated in its programming.

Cautions, the 400 has short rods which tend to increase cylinder wear, so expect any 400 to need a bore job, sometimes you can't get a clean bore as what you can take out isn't enough to smooth the wall. Cooling a 400 especially one that works for a living is touchy where the weather is hot.

Bogie

Well, what it comes down to is I have a running 400 SBC and a seized 350 SBC. Today me and some friends tried to break the 350 loose but it wouldnt budge with what we could do. The 400 will go in atleast until i get the 350 rebuilt. What would you do? Like i said this is my first truck. Gas mileage really isnt an issue. All I want out of the motor is as much power as I can get relatively cheap. I know there are several options such as destroking the 400, or stroking the 350. I am willing to use whatever motor will make more power. I would think the 400 would do this because of the extra 50 CI. Anyways, any input is welcomed.  

have you thaught about putting the 400 in with the carb on it untill you can get the 350 built.  

Yea I have thought of that since my last post. I'm preparing to pull the motors soon and just putting the 400 in as it is. I guess the TBI intake will not bolt up to the 400 because the angle the bolt goes into the intake is different than where it bolts in just like Bogie said. I think im going to rebuild the 350 as cheap/reliable as I can and put it back in and bore the 400 .030" over with relatively high compression (10.5:1-11:1) with a cam, roller rockers, vortec intake and heads, and any other valve train upgrades I can think of inbetween now and then. Hopefully it is as easy to do as it is to say but I doubt it. Also, I was wondering if anyone has any idea what the stock horsepower rating for a 73 400 SBC 2 bolt main is? I would appreciate if someone could tell me. Thanks alot for the input.
                                                                                  -Mike

You can take an electric drill or a die grinder and egg shape the center holes of the TBI intake so that these bolts will pick up the threads of the the 400's heads. Then you drop the intake in place and test the bolt fit. Then while still inplace you put brass tubes inside the bolt holes to protect the threads. Then use a piloted end-mill that has a pilot that will slide inside the brass tube and spotface the intake such that a land is created for the bolt head to snuggle onto when torqued.

Or and this is simpler, machine an adapter that registers against the manifold's bolt face surface on one side and the new  bolt head angle on the other. If you're a careful fabricator this could be done with hand tools.

Bogie

while i halfway understand these ideas, i could not do them myself. Like i said im 15 and this is my first truck. I can unbolt things, and bolt them back on, but im not too great at fabricating. I know you gotta start somewhere but i dont think my intake would be a good thing to start on. Is there an intake I can buy that will bolt up to the 400 heads and use the 350 tbi system? This would be the best for the setup i want to go with. Please let me know. Thanks bogie for all your help. -Mike

OK go back and reread what I've said at the beginning of this and really decide if you're technically up the challange of this swap. The 400 with no changes is far beyond what the computer can deal with and will require at a minimum a custom chip and perhaps larger capacity injectors along with an adjustable pressure regulator. the custom chip is not a catalog hot rod chip for a 100 bucks, this is a genuine made for you limited edition chip that will caost around 3 to 5 hundred dollars. 

You have to be very careful with the engine room electrics so as not to alter nor damage any of the wiring or sensors required by the fuel injection. The 400 will have to use the 350's distributor and coil which may be in the cap or external to the cap, you just have to look. Timing is controlled by the computer, the distributor needs to be set up a 0 degrees. The computer will then establish the base timing as well as the advance.

I'm not aware of an intake that will mate pre 87 heads to TBI. But you can get an adapter that will mount TBI to either a 2 or 4 barrel intake. Go to this URL <<< http://www.tdperformance.com/alphabetical_dir.html >>> then click on "Adapters,TBI" and give it a minute for the PDF file to come up.

Stay connected to us or contact me off line as this can become a real bugger of a swap if you're not careful.

Bogie

Well, I'm pretty sure I will have problems with the swap, I started the project knowing that. This is a learning experience for me :-P thats why its a $350 truck and a $400 motor. I'm hoping in the end it will turn out decent but if that takes me until the end of next summer then oh well. If you were me, would you leave it carburated or swap to TBI. I'm going to replace all the gaskets but I'm not going to re-build completely. I might re-ring and hone, depends on how money looks when i get there. If you wouldnt mind me contacting you once I start putting it all back together you can e-mail me at Metzex08@yahoo.com with your contact information. If not thats OK too and I can continue posting on here. Thanks for your help and sorry I did not read the previous posts more carefully.  

OK, the cost of a carburetor or a computer chip is about the same, around 3-400 dollars for a new one. But!, a carb is adjustable with a minimum of inexpensive parts like jets and power valves, or metering rods depending on whether you choose a Holley or Holley clone like the Demon, or pick a Q-jet or Carter AFB or any of its newer Edlebrock relatives. Fuel injection is always expensive to work on as you're looking at blowing new chips or reprogramming old ones, messing around with pressure regualtors, high pressure pumps, and matching injector flow capacity with engine fuel needs so the things aren't running at more than 70 to 80 percent of their duty cycles (time on versus time off). When on their coils get hot, when off the coils cool down. If you run the injector to where the coil has to be switched on for too much time they overheat and burn out.

If you don't live where a SMOG inspection is requred, I go with a carb as it's much less complicated and less expensive to tune to the engine.

For an 87 the computer is net yet running the transmission if this is an automatic. You will need to use the 400's flywheel or flexplate for balance purposes.

I've got to run to a meeting. But stay in touch.

Bogie

I've decided to go the carb route. The motors are both ready to be pulled. Me and some friends are going to work on the getting them pulled tonight. Right now i cant afford anything as far as carbs go, and the next couple months doesnt look too good. If I do it will be because of asking for it for christmas. I think I am going to have the 400 bored .030 over and the crank turned for undersized bearings. This will be more expensive but hopefully it will be more reliable. What carb/intake combo would you suggest? Let me know, no hurry as money is tight right now. Thanks for all the help. -Metzroth  

I just love it when Santa brings parts for Christmas, my wife thinks this is weird. Don't forget to look on E-bay and at your local wrecking yard and swap meet.

For a 400 inch engine something with a CFM capability of 650 to 750 cfm for a street engine with up to a 220 degree cam at .5 inch lift or a bit less is good. My preferences run to Holley or the Q-jet. The Holley is simpler to maintain and tune, the Q-jet will deliver better fuel economy, not a hugh amount better a mile of 2 more out every gallon.

The Carter comes in third in my book, not that it's bad, it's just a pain to tune. It's more similar to the Qjet than it is to the Holley, using metering rods moving up and down in the jets rather than Holley's seperate main metering and power valved circuits.

Edlebrock sells Carter AFB and AVS clones. They also sold Qjets till recently but the 4MV has been discontinued, too bad it's a nice carb.

The Demon is a Holley clone that uses the same tuning parts.

Bogie

I think i will go with the holley when the time comes. I got the 400 out tonight. Looks like i got some work ahead of me. I'm pulling the 350 tomorrow.  

Got the 400 all taken apart and was trying to get a piston out and it got stuck. was using a metal bar to hit it out (getting new pistons and having bored anyways). My friend said he would go at it awhile and he was being an idiot and took a massive chunk out of the bottom of the cylinder. I'm not even going to risk using this block now. My cousins who race late models have a pre-machined 400 SBC sitting in their shop that they are going to sell me along with an 850 CFM Holley Carb. What intake would you suggest? What is a strong crank/rod combo? I start my first job tomorrow so i will actually be able to start getting some stuff done. What kind of cam/lifters/rockers/springs would you suggest (lift/dur etc.)? I don't mind a rough idle this truck is strictly for fun at the strip and maybe the occasional 5.0 mustang i pull up next to. I've been lookin at intakes but i cant decide what to get. I'm not really knowledgeable when it comes to picking parts. Single plane seems to be more for racing but honestly that is what the motor is for. I'm planning to spend somewhere in the neighborhood of $2,000-$3,000 and would like to make the most hp/toqrque possible. I'm more worried about the strip than the street. I guess i should ask about headers and what to do about heads as well. I don't want to run aluminum heads because i've heard plenty of horror stories about aluminum heads on 400's. I guess i need to help choosing all the major components pretty much. I'd prefer to just have my heads redone but if will be extremely beneficial for me to buy new heads I will do it. At some point I hope to buy a supercharger for the motor but that will be quite a bit later (when i can afford a camaro or something of the sort). Thanks for all the help and suggestions in advance.

Got the 400 all taken apart and was trying to get a piston out and it got stuck. was using a metal bar to hit it out (getting new pistons and having bored anyways). My friend said he would go at it awhile and he was being an idiot and took a massive chunk out of the bottom of the cylinder. I'm not even going to risk using this block now. My cousins who race late models have a pre-machined 400 SBC sitting in their shop that they are going to sell me along with an 850 CFM Holley Carb. What intake would you suggest? What is a strong crank/rod combo? I start my first job tomorrow so i will actually be able to start getting some stuff done. What kind of cam/lifters/rockers/springs would you suggest (lift/dur etc.)? I don't mind a rough idle this truck is strictly for fun at the strip and maybe the occasional 5.0 mustang i pull up next to. I've been lookin at intakes but i cant decide what to get. I'm not really knowledgeable when it comes to picking parts. Single plane seems to be more for racing but honestly that is what the motor is for. I'm planning to spend somewhere in the neighborhood of $2,000-$3,000 and would like to make the most hp/toqrque possible. I'm more worried about the strip than the street. I guess i should ask about headers and what to do about heads as well. I don't want to run aluminum heads because i've heard plenty of horror stories about aluminum heads on 400's. I guess i need to help choosing all the major components pretty much. I'd prefer to just have my heads redone but if will be extremely beneficial for me to buy new heads I will do it. At some point I hope to buy a supercharger for the motor but that will be quite a bit later (when i can afford a camaro or something of the sort). Thanks for all the help and suggestions in advance.

Given your guidelines, I'd recommend copying the "Impersonator" 406 (you can do a search on the CHP site and find the article), though I don't know how well the internals will hold up to a supercharger.