What are pros and cons for one or another?

I've read that 400's might have some cooling issues!?

Throw in all that you know!

This year I'll probably start to make a new engine for my vette and first
I want to decide which way to go, 383, 396, 421, 434 ??

if you can afford it, go big. Motown blocks makes some sick small blocks.

My 2 cents:
400's make more power, thus more heat. In my opinion, the slightly extra heat that a siamesed block makes is not enough to concern yourself with.
Without a doubt, build a 400 if you are considering a 383.
If you wanted to stroke the 400, 3 and 7/8 is all you need. This will yeild a 421. The 434's are nice, but you can never put enough cylinder head to them to make them work to their full potential. On a street driven car anyway. My next build (after the 406 I already have) will likely be 421.

Id like to get a Dart block (very nice piece), go big as possible on the bore and keep the stroker reasonable. Bigger heads=Heavy breather that can take some revs.

Quote:

i went with a 3.75 " reasonable stroker and went .60" over size to make up a 388 c.i but to make up for not going so large, i went all forged light weight components such as crank,rods,pistons,balancer,flywheel so it will rev like theres no tomorrow!!
cheers
glen

I had a 400 small block in my '70 Monte Carlo back in high school in the 80s. It was lightly built with 327/350 hp cam, headers, Weiand single plane, Holley 750 and ignition. The car really hauled ass and I gave the smackdown to a lot of bitch ass punks street racing. I'd normally spin it up to 5,500 rpms.

This car ran hard for years and I even drove it in sub zero temperatures in the winter in the Midwest. I eventually just wore out the rings. I kept the block for years but eventually just sold it when I moved.

I've read it is hard to find a good 400 block. I read a story interviewing David Vizard who said he has only come across a few decent 400 blocks. Evidently core shift is an issue. Plus, you can't really bore them out too much. Also a lot of people would talk about the higher rod angle with the shorter 400 rods.

Cubes rule. Now there are more choices for aftermarket blocks. It is way cheaper to go the 383 route. Coast High Performance has good deals on 383 short blocks. With an aftermarket block you could go ape shit on the cubes, which would be sweet.

I just got back from a ride in my 410 cubic inch stroker Windsor. This puts 440 lb ft of torque to the wheels. It really pushes you back into the seat. I would love to have an engine like that in my vette.

Here is an excerpt from a good story on the Motown blocks:

At this point, it would almost be ridiculous to compare a production 400 block to the new Motown. Thin cylinder walls were a constant problem during the 10-year life span of the 400, siamesed cylinders without larger water jackets meant that low-rpm cooling was an issue, and main webbing weakness affected the engine's durability. All things considered, this was a great option 20 years ago when building a performance motor. Thankfully, things have changed. Nowadays, the best service you can do yourself when looking at a 400 core for a performance-oriented buildup is to look past it. Accomplished engine builder and author David Vizard (www.davidvizard.com) sees no advantage to using most production 400s.

http://www.gmhightechperformance.com/ ... block_solution/index.html

Thanky guys, here is a lot of material for thinking.

My main problem is where I live. Shipping a block to Croatia would cost as block itself.
I was thinking of finding original production block from some truck and fit it with some good internals.
Germany is not so far, and I believe that 400 block can be easily found there.
I'm not so sure it's the best solution anymore.

Does any of you have original production 400 block?

My goal is to build engine that can rev to usable 7000 rpm, but it has to be reliable.

May be a challenge finding a decent 400 block in Germany, considering they are hard to find here in the US. May also be a challenge and expense building it to spin to 7,000 rpms.

It would probably make the most sense in your situation to rebuild your current engine with a 383 stroker kit. That would be the best bang for the buck, especially considering shipping costs to Croatia.

Summit has these kits for around $800-$900.

http://store.summitracing.com/egnsear ... h&DDS=1&N=700+115