I have a dilemma on my hands here.

Local car guy with clean 79 Z28 has a 400 SBC for sale. no heads or intake, splayed main caps, needs a rod bearing. has a 7 quart oil pan (for 3rd gen use), 200 dollar special harmonic balancer, and oil pump all for $425. FLywheel included but Like I said, no heads or intake.

My main part is should I buy the 400 or get a 350? I was told the 400 deal wasnt too good but I thought it was, cause they are pretty good motors. I want to buy some good aftermarket aluminum heads liek AFR 195's and put them on, put a good cam in it, and put my Edelbrock Pro FLow FI setup on it. It will be going in my 92 RS Camaro. The plan is to build the motor, put either a TH350, TH400, stock 700R4, or maybe a T56 behind it, 3.73 gears, SFC's, and lter in the season hook up a N.O.S or Nitrous Express 150HP shot. Also, would a y-pipe setup hooked up to some shorty headers support 350-450 HP easily or would I be best f with some duals/h-pipe? Just lookin here, because Im aobut to buy my block and want to know your opinionsd. thanks.

 

425 dollars for a 400 with a bad rod, that means you need to grind the crank, resize the rods.

Your pretty much buying a door stop.

You can get an entire vortec 350 for less than that.

 

400 hands down

Just to get splayed caps installed and line bore is big bux.
as long as the rod in question didnt beat the crank to death

 

i've seen 400 blocks sell in that price range.

 

Why spend 425 when you can get a 350 for 50 bucks. I guess it depends on budget. I wouldnt.

 

I've seen 400sbc balanced, decent rods, forged pistons, block was blueprinted (squared) with no heads, with a bad rod going for $300. IMO, stay away from the 400 because once it's apart, you may find that it will cost a ton to fix it.
On the other hand, you could take the 350 crank and put it in the 400 block and build a 377 that will be a rocket ship. (you have to use the crappy spacer-bearings though).

 

The 400 would be a better performance choice. A 350 is a good engine but the extra displacment of the 400 will yeild better results hands down.

 

The cost of splayed main caps, plus the machine work to install them, is about $400. So if you look at it that way, by buying that block you're getting the machine work done, and then whatever else comes with the spayed caps (block, crank, rods, pistons, balancer, etc.) is costing you $25. So, if you are intending to do that to your block anyway, it's a good deal. If you're not intending to do it, it's not a good deal.

In no case would I remove any of the cubes from a 400. It's laughable to think that somehow you'll make a motor more powerful by decreasing its CID. Think of a 377 as a 350 bored out .125"..... so what's the big deal about that? You take a 350 block, bore it out .030"; does that make it much faster? Hmmm..... how about .060"? Noticeable difference there? I don't think so. What about .090? .125"? A little more power now, since the inches are adding up; but we haven't revolutionized the science of engine building. Certainly we haven't taken our 350 and turned it into a "rocket ship". So how can you possibly "improve" a 400, by shortening the stroke? Ask anyone that's changed their 350 into a 383, which is of course the exact same stroke change except in reverse, how much they "lost" by doing that.

The rod(s) may or may not be damaged. Big risk there. If the rod itself is still good, then all you have to do to repair is is to crank-kit it, and get all the metal shavings out of it if there are any. If the rod needs repair, you'll have to remove the piston, which means ringing at least the one cyl at a bare minimum. But, in that case there would probably be enough metal in it that you don't want to put it back together without a good trip to the car wash with rifle brushes, which means a full set of rings and a honing too.

I'd also be concerned with the usage the motor has seen. You may be looking at a 300-lap short block that has 305 laps on it, which is why the rod bearing is used up. Who knows what else is also used up.... rod bolts most especially.

 

The only thing a 400 has going for it over a run-of-the-mill 350 is cubic inches... you take that away, then whats the point?

I say build the 400, but only if its gonna stay 400 (or more) inches.

 

Well my plan would be to take it to a machine shop, have them bore it .030 over, put new rods, pistons, rings and bearings in to make a good reliable strong bottom end, because of a probably chance of Nitrous later on down the road. Plus, Ive been looking at some AFR 195's for this.

I spoke to the owner of the block and he used to build motors. He told me that the knock wasnt very bad. Thing is, he bought the motor for liek 2000 completely balanced, blueprinted and built. He dropped it in his 79 camaro and drove it 50 miles when some of the lifters collapsed, then he put a differant set of heads on it after he fixed it and then it began knocking a couple weeks later and he pulled it out and dropped a 355 into it, put his Dart heads on it and has had the 400 sitting for a few months now. He said it isnt very bad at all and he was going to fix it but he was so mad that he didnt want to mess with it anymore and he had just gotten his hands on a 355 so he proceeded to drop it in. But I am taken the guys words liek a grain of salt, cause he could be BS'in me hopin ill buy it. Dunno really.

 

If I was the betting kind, I'd bet money it's already .030" over, or more.

Lifters don't "collapse". That's newbie / BS code for "The valve train was screwed up and made alot of noise and I couldn't find it or wasn't willing to fix it right".

No knock in a motor somebody is selling is ever "very bad". On the other hand, how would it be possible for any knock not to be "very bad"? Can someone be "just a little" pregnant? It's a yes/no kind of thing; either it was good, or it knocked.

It might be a good deal, like I said; but it also might be a pile of useless garbage. Approach it carefully. Measure everything you can, look at the rod bearing and crank journal in question, just generally get as much real info (NOT used-car-salesman monkey-spank) as you can, so you know what you're getting into. Don't get a bunch of stars in your eyes and blindly accept what the PO is telling you as "truth". Do your research, and don't be either mislead or scared off, without knowing the whole truth.

 

As RB said, find out the physical aspects of this engine before you buy it. Find out how far it has been bored. MANY 400's cant be bored past .030. I have personally taken a couple to the junk yard because of this. Couldnt pass the sonic test. Core shift is prominent in 400 blocks among other issues. One of the reasons I would rather stroke a 350 than start with a 400, even if i cant make the same cubes.

 

Could have swore I seen a wet sleeve 400 race block floating on one of those off brand catalogs, that sure would be nice to have.

You say it needs a rod bearing, is the engine apart??????

 

The point was RBL, is that he had a good 400 block with questionable internals. 350 guts are a dime -a- dozen.
But the 377s that I've seen (and I'll admit I haven't seen them all) seem to perform better than the 383's.

 

That may be true, as far as it goes; but on the other hand, a NEW USA made cast crank that's a little better than a stock one, and considerably better prepped, is less than $300 at Lunati. By the time you buy a junk 350 crank core, work it up to the same level as the Lunati, and buy bearing spacers, you're into about the same money; and you get about 7-8% less inches that way, and therefore 7-8% less power. On a 1HP per cu in motor, that's somewhere near about 30 HP you give away. By the usual rule of thumb of $10 per HP, that means that it's worth somewhere near $300 to keep it a 400.

CID is by far the cheapest HP money can buy, comparing stock CIDs to each other.

 

Not trying to disagree with anyones opinion here,but I don't understand thinking the 377 isn't a good idea.There is a bloke that lives near me with a Stealth B6 race car(a track only GT racer).It has a 377 NA engine producing well over 600hp.I must admit it is a bit exotic with a Rodec aluminium block,18* heads,Kinsler injection etc,etc.But my point is that if someone with enough money to build pretty much any motor,why destroke it to a 377 without a good reason.

 

No one said the 377 was "bad", just that the 400 is better!

 

Either he is doing it to meet the limitations of his class, or he lacks the common sense to take advantage of the extra cubic inches he is missing.

600hp doesnt mean anything. I can make almost any SBC engine achieve 600hp. A 350, 377, 377(the other way), 383, 400 you name it. There is nothing magical about the number 377. I always laugh when someone tells me they purposely de-stroked a 400 to make a 377. It usually has some purpose such as "The shorter stroke makes it rev easier" or some other nonsense babble attached to it.

Why take away cubes (potential) when you dont have too?

 

The car isn't built to a class limit.Don't get me wrong,I don't really understand it myself.All I was saying was there must be a plausible reason why these cars are built with that particular size engine.I'm curious myself.BTW the road going version of the same car holds the 2nd fastest time in the world for 0-100-0mph(may even be the world record by now).

 

Thats a Bad#%ss lookin car...Dont know about that "Visit Bahrain" part tho....
Later
Steve