I had a great deal on a 383 fall through recently (the guy's wife didn't like the deal her husband made with me). So back to the drawing board (or craigslist or wherever).

I currently have a tired out NOM 350 in the car and may eventually build a stroker out of it purely because I want the fun of doing it. In the meantime, I'm looking for other options for the car (cheap and temporary craigslist motor to keep the car driveable, possibly). Also, please save all mention of Vortec motors or the great value and power I can get out of modern roller setups, I'm aware, just not interested.

My real question to the engine gurus out there is kind of a fundamental one...what are the advantages/disadvantages/pros/cons of using a 350 vs a 400 sbc for the basis for my new motor? Obviously a 383 is an attractive option, these days, and you can build a torquey motor for a good price. What about a 400? There are obviously more cubes available, which is never a bad thing. Also, for some reason, there seems to be quite a few 400's around lately (I've been looking every day for years and it seems like there are more than usual lately). I guess the problem could be, I don't know much about the 400...

I should mention, the car is purely a driver, no racing, etc. (unless I put a 500 hp 406 under the hood in the near future or something). Its just a third vehicle that I like to drive just for fun (and, like most of us, work on). Its a 4 speed car with a 3.70 rear end. The only major thing I want to keep are my sidepipes. They are GM pipes (ie. cork), so they will inevitably hurt performance of whatever engine I put in the car, as I will have to keep the junk manifolds. Still, I love the look and sound and must keep.

I realize I am kind of talking about two different things here and that's part of the problem...on one hand, I'm talking about finding a cheap, temporary motor to put in the car while I build what I really want. But then, I also realize, I may not know WHAT I want...I guess in the end, I want more power than I have now but not so much that I'm going to break every other part of the car. And I want it at an affordable (reasonable) price. That's not too much to ask is it???

Thanks in advance!

 

350s are cheap and available, and rebuild parts are usually less expensive than for just about any other size engine. Going 383 is a very easy and cheap upgrade, as cast cranks are available for as little as $200...if the stock crank needs turning, you are halfway there.

400s are great motors that were hampered by their original factory form; low compression, 2 bl carbs, installed in heavier vehicles. They have great potential, however. The only drawbacks I have found to going to a 400 are 1)availability of good cores (which you say isn't a problem in your area) and 2) the need for a custom flywheel in a 4spd application. Some say they are more prone to overheating, but that hasn't been my experience. Some have an issue with the short 5.65 rods, but they're fine in most applications (though if you rebuild it I'd use a longer 5.7 rod). Also, if you use non-400 heads (the stock heads are awful), be sure they are drilled with the steam holes before installing them.

 

I'm building a 406 now and if you like a good torque motor up to 5500 RPMs. 400s are the $hit!

 

Go for the cubes. Depends on how far you want to go during rebuilding, but I would agree to use at least the 5.7 rods to get lighter pistons (forged-even cheap ones- no Hypereutectics).

Use a large CC port head (200+cc's), port ex manifolds as much as possible, put 3" mufflers under the side pipe covers....and use a decent cam. I'd put a nice solid flat tappet in it....it will run killer! You can build a lot of power with a basic 400.

Flywheel isn't too hard to find....and if you change pistons and rods, you might be able to internally balance it without too much trouble and use regular balancer and flywheel.

JIM

 

There's no replacement for displacement Seriously, the cost and driveability of a build is a result of the proportion of HP to CID. A 383 engine making 425HP (1.1 HP/CID) is going to be more driveable than a 350 making the same power level (1.2 HP/CID). This is the appeal of big blocks - tons of power from a relatively mild engine.

Good 400 blocks are becoming harder to find - they're out there but many have been through a previous rebuild. I agree that the overheating problems are a myth, but it is fair to say that a 400 is more sensitive to a marginal cooling system.

Generally, the cheapest route as noted is a 383 stroker. Unless your budget will not allow the cost IMHO there's no reason NOT to build a 383 today.

[Broken Record ON]
Budget is always the first step. Usage drives the cam choice, cam drives head choice and we build the engine around the heads...and budget makes the hard decisions.
[Broken Record OFF]

 

There is no good substitute for cubic inches and RPM is a poor substitiute.

-Mark.