400 Small block engine

[WarMonger]

Ok, I have a 70 C20 with a 350 motor with a brand new turbo 350 trans. Motor is getting old and wore out. I think I want to to a small block 400? Where do you guys think is the best place to get a crate long block? DO I need to change motor mounts from a 350 to a 400? I will thank everyone now, I know there are some experts here.

[wbc409]

External dimensions of all first Gen small blocks are the same. You might have a problem finding a 400 crate motor with an original GM block. 400 ' s are getting hard to find. I suppose I should have asked if you were going small block or big block.

[WarMonger]

Originally Posted by wbc409

External dimensions of all first Gen small blocks are the same. You might have a problem finding a 400 crate motor with an original GM block. 400 ' s are getting hard to find. I suppose I should have asked if you were going small block or big block.

I was thinking small block? Now should i try to find a small block 400 crate motor or just go with a 383 crate motor?

[wbc409]

If you really want the 400 it never hurts to look or make a few calls. But don't be surprised if you find one and it uses an aftermarket block. This will be reflected in the price. You could talk to local machine shops and see if they have one laying around that is able to be rebuilt.

[Warrens69GMC]

Originally Posted by WarMonger

I was thinking small block? Now should i try to find a small block 400 crate motor or just go with a 383 crate motor?

I would go 383, roller cam

[CarterD2015]

I would go with a 383 because the small block 400 doesn't have water jackets between the cylinders. Because of this it tends to run hotter. I have heard that this was the downfall of the sb400.
Posted via Mobile Device

[ol_skool_chevy]

I would go 454....400 small blocks more prone to overheating than other small blocks. use the 1003 high- performance Fel-Pro head gasket has larger 7/16-inch coolant passages that greater coolant flow to prevent excessive heat buildup between the center cylinders. and use 3 core..

[MARKDTN]

Why do you want a 400 or a 383?

There is a lot that goes into a new engine decision. Bigger is not always better. It could be-just depends on what you want it to do.

[WarMonger]

Originally Posted by MARKDTN

Why do you want a 400 or a 383?

There is a lot that goes into a new engine decision. Bigger is not always better. It could be-just depends on what you want it to do.

I need a rebuild/new motor. Mine is burning oil and leaking oil. Since i have a brand new trans and a locker in the rear end, I was going to put some horse power to it all.

[Lattimer]

Originally Posted by WarMonger

I need a rebuild/new motor. Mine is burning oil and leaking oil. Since i have a brand new trans and a locker in the rear end, I was going to put some horse power to it all.

400 small block seems like an odd choice. They are kinda rare now and were the oddball of the factory small blocks. Their real claim to fame was donating their cranks to make the 383.

How much power do you want? A crate 383 can get you 450 HP pretty easy. http://www.jegs.com/p/Chevrolet-Perf...54258/10002/-1

Rebuilding your 350 correctly can get you into the high 300's, and probably less expensive than a 383. All depends on what you want and what you have to spend.

[WarMonger]

Lots of good ideas you guys are throwing out. I might have to rethink everything I though?

[Lattimer]

Originally Posted by WarMonger

Lots of good ideas you guys are throwing out. I might have to rethink everything I though?

First thing is how much power do you really want/need.

I decided when I bought my engine that anything over 350 would be plenty for what I'm doing with the truck, which is basically cruising around and playing a little. I wound up with a crate 350 that engine dyno'd 382 HP. http://www.jegs.com/p/Blueprint-Engi...61054/10002/-1
I would have liked to go with a roller cam, but cost was a factor. I've got a little over 5000 miles on it, and pretty happy with it. With the manual trans, open rear and tires I run, its really more than the truck can put to the ground. Wet roads are really difficult....LOL

[67 cst swb]

Originally Posted by WarMonger

Lots of good ideas you guys are throwing out. I might have to rethink everything I though?

I think you are over thinking this.
Although the cubic inch does play a role in the potential performance of an engine. It really is based on the components, pieces and specifics used in the build. It is possible to build a 283ci to walk circles around a 400ci.
So, focus more on what you want to achieve.
You already have a 350. Find some good heads (your engine may already have good flowing heads, check the casting numbers), then choose a good camshaft (read the description of the cam) and just rebuild what you have. You would be surprised what a flat top piston engine with a good set of heads and a decent cam with do for performance.
Although its kinda cool to have "aluminum heads" on your engine, there is no huge advantage to running them. What a head flows is what a head flows. Sure if you can get aluminum heads that flow great for about the same price as steel heads, then definitely get the aluminum heads. Just remember... fuel and air doesn't care what it is flowing through.
That being said, you can run a slightly higher compression with aluminum as it is less likely to ping and detonation. But that is all in a whole higher performance level.
Also there is a weight savings advantage, but not really worth $500.00 more in a street vehicle if they are costing you that much more.
I would go with a 350 or 383 engine before installing a 400.
As for small block versus big block. I suggest staying with a small block. Everything is already in place to reinstall a small block. Saves on the wallet.

[SS Tim]

Sorry I just had to do this! :-)

[MARKDTN]

Originally Posted by WarMonger

I need a rebuild/new motor. Mine is burning oil and leaking oil. Since i have a brand new trans and a locker in the rear end, I was going to put some horse power to it all.

I will probably get flamed, but a basic crate 350 with Tuned Port fuel injection added will give you a lot of oomph (especially low end) and keep the mileage reasonable. That will be way less $$ than a crate 383 or 400. It will allow you to use your existing transmission, exhaust, and accessories.

[WarMonger]

I was thinking about this? What do you guys think?

http://www.ebay.com/itm/281660964041...%3AMEBIDX%3AIT

[Lattimer]

Originally Posted by SS Tim

Sorry I just had to do this! :-)

That looks cheap......

[WarMonger]

Originally Posted by Lattimer

That looks cheap......

Thats ok, thats what I wanted to know?

[Lattimer]

Originally Posted by WarMonger

I was thinking about this? What do you guys think?

http://www.ebay.com/itm/281660964041...%3AMEBIDX%3AIT

I personally would not buy an engine on Ebay.

[Lattimer]

Originally Posted by WarMonger

Thats ok, thats what I wanted to know?

That particular smart-a$$ comment was in reference to the aftermarket block. I'm betting they get a pretty penny for those.

Ebay engine is a little too cheap, plus I wouldn't trust it on Ebay. Too many scams on there. I don't care too much if somebody steals $20 on a part I'm buying, but $3k is a big deal.

Either find a local engine builder with a good reputation, or buy a crate from a reputable company.

[WarMonger]

Originally Posted by Lattimer

That particular smart-a$$ comment was in reference to the aftermarket block. I'm betting they get a pretty penny for those.

Ebay engine is a little too cheap, plus I wouldn't trust it on Ebay. Too many scams on there. I don't care too much if somebody steals $20 on a part I'm buying, but $3k is a big deal.

Either find a local engine builder with a good reputation, or buy a crate from a reputable company.

I will start looking around for good local engine builders.

Thanks

[67 cst swb]

Originally Posted by WarMonger

I will start looking around for good local engine builders.

Thanks

Good Choice.
Find a good set of heads and get some help deciding on which cam to go with, be sure that you know what rear gears you have and what transmission you will be running. I also highly recommend a 500-600 rpm over stock stall convertor if running a TH350.
My set up was 3.73 rear gears, 30" tall rear tire, TH350 trans, ok flowing heads (don't remember the casting number) and a .420/.443 lift 204/214 duration cam... the little over stock stall made the truck way fun to drive, while still being very easy to drive anywhere. If I build another one , I will go slightly larger on the cam. But not exceed .480 lift and not more that 230 duration, maybe about .460 -.470 lift and 218-228 duration area.
OK, enough of my rambling.

[truckster]

I'm personally a fan of the SB400. They are externally balanced, so you would need a different balancer and flex plate. As far as heat, they're no more prone to overheating than any other SBC. You just need to make sure your cooling system is up to par. If you're going with a new engine, you should be replacing the water pump and replacing or rodding the radiator as well, regardless of what engine you're installing.

Because the SB400 is getting rare, they can be really hard to find and kind of expensive. For my rebuild, I'm going with a 5.7 Vortec. It gets me the roller cam and the Vortec heads that flow much better. I'm keeping it somewhat old school, so the Vortec is getting an HEI distributor and a Quadrajet.

It's your truck, so do with it what you want. But it helps to ask a lot of questions before you start spending cash.

[67 cst swb]

Originally Posted by SS Tim

Sorry I just had to do this! :-)

I will take that block SS Tim. I will be over on Friday to pick it up ! HaHaHa !!!

[Eddie H.]

I like a small block 400. I have been running one in my 69 GMC for more than 20 years without any problems. The only 400 crate engines that I know of use aftermarket blocks, and they are pretty pricey, but if you can find a good rebuildable 400 SB core, and a good machine shop, you can build your own, or have them build it for you. Having said that, there's really nothing wrong with a good 350 or 383. You can get plenty of power out of either one.