Thread: 400 ci weak?

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I'm probably opening a can of worms here and I don't mean too, but I'm slightly confused. My sbc knowledge isn't great and it mostly stems from about thirty years ago when my brother built a 34 Ford p/u with a mouse motor Jag suspension etc, and I owned a '66 vette 327/350hp. Most of my performance cravings have been relieved with motorcycle power since then.

Back then the common belief was the 400 block with it's siamesed cylinder bores could make a good high torque truck engine but would not hold up to high horse, high RPM street/strip use. "Just build a 383" was the often heard advise.

Now that I am looking at street rods again I am seeing ads for crate motors and engine kits with 427ci and larger sbc. Wow!

I've done a search on this forum and for the most part people are still saying "just build a 383" with a few swearing their 600 horse 400ci mills run forever.

I won't doubt any individuals personal experience. There are exceptions to everything I guess and I REALLY DO NOT want to start a war.

I guess what I really want to know is how do they get 427 or more cubes out of a sbc? Stroke a 400? It can't be bored anymore can it? What's the biggest mouse out there? With controversies over 400ci, how in the world will anything bigger survive?

Great forum! Lot's of good people on here!

Thanks for your time.

The 400SB did have some problems related to heat and the Siamese cylinder construction compounded the problems. There are some fixes that work (as simple as a 3/8" hole to very elaborate machine shop work) but many people believe that starting with a 350 4 bolt is the best way to make a lot of power in the small block Chevy world.

World Products (and others) market a 427 CI small block (4.125 bore x 4" stroke) that produces well in excess of 550 horsepower with 525 F/P of torque - it's spendy, but some folks want to have the small block look.

If you want lots of thump - talk to Pat about a big block Chevy. He's the master and has forgotten more than most of us will know about building bullet proof big blocks with a reasonable outlay of cash (remember - you usually get what you pay for)..

Regards,
Glenn

The 400's got a bad rap when the 4-bolt block was introduced. There was insufficient main saddle webbing strength in the block and you'd end up running over the rotating assembly if you tried to extract too much power from one. The 2-bolt block is a better choice if you're intending to use a production block.

Also, the 400's in general got a bad rap when some dunderhead bolted 350 heads onto his 400 block and it overheated because he didn't understand that you had to drill the 350 heads for steam holes to prevent overheating.
http://www.gregsengine.com/350to400.htm

I concur with Glenn about using the BBC when you intend hp levels approaching 600.

Production 400 blocks can be increased to 434, but going to a 454 small block will require using an aftermarket block.
http://www.speedomotive.com/s-86-sbchevy-400.aspx

The 383 makes a fine motor, but if you have access to a good 400 2-bolt block, that would be my choice. There's no replacement for displacement. Look at the dyno'd results of a "406 street motor" here on the AFR site. The components are listed, so it's just a "plug-and-play" situation. Look at "550 HP 406 Street Engine".
http://www.airflowresearch.com/chevy_dyno.php

420 inch motors are common in UMP modified circle burners,running high dollar brodix aluminum heads,lots of compression,and burning alky and they seem to be reliable. I do know a lot of them are built using a 400 block.

there are actually 454 cubic inch small blocks

If you are building a street rod that you want tobe a driver, come to the future and take a look at the LS based Generation III and IV motors. They are available in a number of vehicles including late maodel trucks and SUVs. They will make great power and with EFI abd computer control will even get great gas mileage too, Best of both worlds. I have an LS1 in my Studebaker and just love it.

Pat