School me on SBC-400 (Good engine-Bad engine)?

crawler nut · Jan 27, 2013

Which ones to go for, an which ones to stay away from. Ive been told to stay away from 4 bolt mains.
So will they run hot in a crawler?
I have been told from a couple engine builders they will no longer build a 406 out of a GM block, beacuse of cylinders cracking because of the all ready thin walls.
SCHOOL ME PLEASE. Thanks

tommyswheelin · Jan 27, 2013

I got a 400 .40 flat tops 6" rods with pro 1 alum heads. Got all the power in the world. It has a small cam. Only ever blow 1 up in race car due to valve hitting pistion .

Bronco Buster · Jan 27, 2013

I ran a 406 4 bolt main for about a year on the street with no issues. It wasn't a full out drag motor but it was built healthy with 10 to 1's and some head work. I also know a few round track guys that run 406's. An engine builder would rather you build a 383 and him charge you for all of the machine work than just bore a block and you build a 406. My $.02

crawler nut · Jan 27, 2013

tommyswheelin said:
I got a 400 .40 flat tops 6" rods with pro 1 alum heads. Got all the power in the world. It has a small cam. Only ever blow 1 up in race car due to valve hitting pistion .

Its going in a crawler. I worried about the slow speed, an high RPMs an running hot.
Is it true that the most preferred 400 is a 2 bolt main. The one im looking at is castin number 509 it is a 2 bolt main.

Bronco Buster · Jan 27, 2013

If you think it will run hot at slow speed use a good high flow (manual or electric) water pump and some good (taurus) electric fans. If you go the all electric route it will flow the same at any speed. At high rpms approaching redline for an extended period any engine will run hot under load.

Elliott · Jan 27, 2013

Save your money and put a 6 liter in it, more power and fuel injection!As bad as I hate to admit it old school motors don't belong in crawlers anymore,dollar for dollar there is no comparison.

hink311 · Jan 27, 2013

Elliott said:
Save your money and put a 6 liter in it, more power and fuel injection!As bad as I hate to admit it old school motors don't belong in crawlers anymore,dollar for dollar there is no comparison.

true in stock form, if you start buying after market parts for a late model motor , it is cheaper to build old school. ive personaly never been able to run a stock motor ,i like a little more spank in my crank. stock parts tend not to live above 7000 rpm.

hink311 · Jan 27, 2013

by the way ,if your not interested in that block, i am .

TBItoy · Jan 28, 2013

crawler nut said:
Its going in a crawler. I worried about the slow speed, an high RPMs an running hot.
Is it true that the most preferred 400 is a 2 bolt main. The one im looking at is castin number 509 it is a 2 bolt main.

When my buddy Cody worked as a floor sweep at B&B racing engines, he built a 2 bolt main 400 SBC, 406ci, Dart Pro 1 al heads (hand ported and flow benched), full Comp cams roller valve train (lifters/shaft mounted rockers), fully balanced, etc.

Made 505hp/512tq. and they turned it 9,000 rpm on the dyno. And it made over 300 lb/ft tq over 1800 rpm. Stump puller for sure.

Impressive to say the least.

bad thing is, after dyno tuning, the engine was supposed to go in my Cody/s 65 Chevy truck... Which is still not finished and the engine is still sitting on the stand... for 7 years.

muslcr71 · Jan 28, 2013

i am in the middle building a cj7 crawler and its has a '76 sbc 400ci 4bolt with few add ons,motor spotless inside of motor,(looks to have less than a 100k) stout motor and revs quick and tight.........and i was wondering the same thang,my dad had a 400 in his 69 camaro and street raced with it and it last the whole time in the car.....but im going to run 400ci tell i cant or suming comes up better later.

crawler nut · Jan 28, 2013

hink311 said:
by the way ,if your not interested in that block, i am .

It is a complete motor, All acc. an everything. I will prob throw the stock heads away, As I hear they are junk. But I want to get the casting numbers off of them also. I know another guy that has several 400 blocks if your interested in one.

doctordick · Jan 28, 2013

SBC 400 got a bad rap for overheating. Guys were putting 350 heads on them without drilling the steam holes. My brother and I ran 400s in dirt cars for years, there's nothing wrong with them, either 2 or 4 bolt, but we ran 4 bolts when we could find them. We built a lot of 377s (400 block/350 crank) revs quick and makes good HP since this combination is close to the theoretical ideal bore/stroke ratio. The bottom line is that if you build it right it will stay together and if you have a good top end combination (heads, cam, valvetrain and intake) you'll get good performance.

Macman · Jan 28, 2013

509's are the thinnest of the 400's. The ideal is 511 2 bolt then put splayed caps on it. The factory 4 bolts are ok caps just seem a lil weak, The next best block is the 817 block imo. I had a 408 that dynoed 682 to the real wheels in a lil s-10 back several years ago and never had any problems with it. I found out by sonic testing a few different blocks that some of the 511 castings were as thick as some of the aftermarket blocks.