Ive done some research as far as 400s go, but i havent been luck in that said search. worst case scenario i get links to threads i missed right? Im looking in to buying a 400 sbc from a guy I had met recently, hes selling for 300$, but i am wanting to swap it in to my 86 iroc and get rid of the 305.
he has told me that the engine has had the complete bottom end redone. forged everything if im not mistaken. it is currently in his late 60s pickup and i saw a video on his phone of it running. it is bored and is a 406 now, and is at 900 miles on the break in. he also said the heads could use redoing and such, and i figured that would be too bad. Im sure you all know there are (stupid) questions coming Im aware of the steam ports on the original heads, but he has a set of double-pump heads from a 327, do they need steam ports?
I would REALLY like to reuse my current TPI system. what would need to be done as far as that goes? do i need the computer retuned or anything for that?
also, will it mount right up to the original engine mounts, or will i have to change them? I am also wanting to keep all my current accessories, he has a serpentine setup on the engine, and the ac is on as well. as for the transmission, Im going to get rid of my 7004r4 and im looking for a six speed. will it bolt right up? or is there an adapter? im not completely savvy as far as all this goes, so I may be unknowingly be asking completely retarded questions (i apologize), but like i said, not sure what all to ask. if there is anymore info you think I need to know or would like to know please feel free to indulge me!

ive tried that setup and it ran out of air before i could do much the best way for a 400 to run is carb i have it now and sometimes cant hold on to it and any head other then the 400 heads need steam hoseand you would need to get your pcm tuned ether way so i would say carb yes tpi no hope this helps just my opinion

Forget old factory heads. If you have a bass boat, you can use them for an anchor; otherwise, pass on them. The ones as old as you're talking about probably don't even have hardened seats.

A set of upgraded Vortec heads will do much, much better. Plan on a thorough TPI upgrade - might as well go with the Holley/Weiand Stealth Ram, which comes in a Vortec version.

Yes, also plan on computer retuning.

A 6-speed from a '93-'97 f-body will fit, but you will need a special flywheel for the external balance of the 400 (you would need a different flywheel, anyway, since 400's are 2-piece rear main seal).

alright, good to know, so if i were to get a higher-flowing say dual CAI, the TPI still wouldnt be able to use the air?

The TPI design is the restriction, not the air filter.

The TPI system can be upgraded to flow alot of air. These upgrades can be expensive and even with the hi flow parts, you need to do alot of port work on the factry plenum and preferrably on the base to make it flow it's best. Even with all that, a larger motor moves more air with each revolution and will run out of air sooner with any given intake than a smaller motor.

Still, I have seen tests where a 383 made 500ftlbs of torque and 400hp even with a tiny factory TPI system. That is huge power that will make your car a beast. The key to making TPI work is first developing a motor combo that works. five7 mentioned the Vortec heads which are good for the price. I disagree however with using the Vortec version of the Stealth ram. The Vortecs, unless they're extensively worked over don't flow enough to make it worthwhile. A TPI with ported vortec base and plenum will do just as well with those heads.

Tuning will then become the key and that can get expensive whether you use something like tuner pro or a standalone programmable EFI controller. Either way you will need to have the system dialed in by a professional on the dyno unless you are ready to really educate yourself in the finer points of engine performance. Of course, you pretty much need to educate yourself in order to make this engine work in the first place. A good resource for engines 101 is HP books. I see that Amazon.com carries these. Look for their books on building the small block chevy and start reading.

if you go with the shealth ram they(po po) will fine you it dont have egr but if you go with superram may help but look at the basics more air and fuel more power do your homework on the intake and the block but if you want to stay with the 400 look for a 509 block it was made better

Before you get deer in the headlights wide eyed about 500 lb of torque and 400 hp,you need to go back and find exactly what parts you have in the bottom end.I seriously doubt you have forged "everything" for a purchase price of $300.

Agreed. Honestly, I'd be surprised if it was even competently rebuilt for that kind of money. It sounds like somebody's trying to unload a problem to me.

yeah, ill have to get in there and find out. its not going to be a buy-and-drop deal. I still have the 305 in the camaro now. so while im getting the double hump heads fixed, ill also take a look in its bottom end. this will be my first swap, and so far im learning a good bit. thanks guys!

Again, scrap the double hump head idea. They're an old archaic design. You will make more HP and torque from a stock set of Vortec heads then you will from some hopped up double hump's. Not to mention a lot of double humps dont even have accessory holes drilled/tapped into them leaving you with more work to do and more money to spend.

Any head can be made to work on a 400 block. As for the steam holes, you put a 400 head gasket onto any head and drill out the 1/4" holes required for the steam ports into the head.

Stock 400 heads were never a performance head. They were all smog heads. Horsepower is in air flow through the head. The larger the displacement, the more air is needed in the engine to make power. Going backwards with camel heads is the wrong way to go. Any aftermarket or newer GM head such as Vortec are much better than heads designed for 1960-1970's engines. Unless you're after some sort of retro look, don't even bother with the old heads. Even if they were free, they wouldn't be worth rebuilding unless you could do all the work yourself. For what you would pay someone to update the old heads, you could have bought new heads. 40 years ago, camel heads were the hot ticket for performance compared to regular production heads. Technology has come a long way and the cost of aftermarket performance parts has plummeted since then. Even aluminum heads are considered inexpensive.

I also agree that $300 for a forged everything bottom end sounds too good to be true but sometimes a seller is willing to make a sacrifice just to move an item. I've gotten some fantastic deals myself but knew what I was buying and knew what it was really worth. My last deal was some 12 way double adjustable shocks with 2 sets of springs for $300. To buy new, it would have cost me around $1000 so deals are out there.

so vortec it is then? wha exactly should I look for as far as they go?

Man-you do really need to do some research on you own!!.Again,no 500lbs of torque or 400 hp on vortec heads.Look,buy from a search on line the David Vizard book how to build SBC hp.Read it cover to cover.Seriously,this is a matter of giving a man a fish vs teaching a man to fish.The book teaches you.

http://sdparts.com/details/scoggin-d...nter/sd8060ra2

You'll need two.

The Vortecs are a good value for the price. For what it's worth, the heads used in the Comp Cams TPI power test that I referred to above were Trick Flow. They didn't mention the specific model and TFS make several different levels of heads, but I would imagine they were the base 23 degree model (maybe even the CNC ported 23 degree heads) as these are a good street/strip head. They are also about $1,500 with valves installed(without CNC). About double the price of the Vortecs.

Yes, it can definitely be made to flow a lot of air, even with the stock runners. I did mucho port work to my TPI setup and flow will never be a problem again, even with a 400-SBC, but if I had to do it all over again, I would definitely go the LT1 conversion route. The welding would have been much easier for me to do, as opposed to all of the hours spent porting. These pics are before the polishing, but it will at least give the OP an idea...