Most Power from Stock 400-509 casting?

[econo racer]

Would a 600 hp 434 last a few yrs bracket racing at 12-1 compression shifting at 6400 rpm. Using a scat crank and rods. will be run on E85 only

[mag2555]

With no detonation taking place , why not

[steve316]

Why tie up money in a block like a 509 casting; when you can buy a dart shp ( shp pro better yet) for a few dollars more. You don't have the clearance
problems, thin cylinder walls or the mains wanting to walk. Also the wore out lifter bores, sell your block to someone who want a low hp street engine.
I would not use a oem casting for anything over 450 hp. Just my opinion, good luck.

[Racing68]

I know without splayed caps they only last about 15-20 nights about 500-700 laps in a dirt circle track car. Depending on how many passes you make a year it should last at least 2 years, longer if it's 1/8 mile. Also for these reasons I have not used a stock 400 block in a race engine in well over a decade.

[Lizardracing]

I know without splayed caps they only last about 15-20 nights about 500-700 laps in a dirt circle track car. Depending on how many passes you make a year it should last at least 2 years, longer if it's 1/8 mile. Also for these reasons I have not used a stock 400 block in a race engine in well over a decade.

Lots of guys in my area running 509 GM blocks ate 550-625 in circle track cars for several seasons. I'm one of them.
A aftermarket block is still a good idea but they also cost twice the amount, not just a few dollars more.

I have a $1000 in machine work on my current 406. A dart block starts at $1800, then needs finish worked and ends up at $2200.....Tha'ts not exactly a few dollars more.

[mt-engines]

I have built quite a few in the low to mid 700hp range that are still being used today without issue. 377-434.

I have one thats getting a freshen up here at the moment that hasn't even had the springs changed since it was built(2006). no signs of fretting on the caps or oiling issues, overheating, cracking etc. As far as power goes, it was never on the dyno but showed over 600hp worth of et. Just a 7000rpm bracket engine.

I have also had luck with one that made near 800whp with an 8:71 blower, guy has been cruising it to car shows for probably 6 years. Ive seen more engines destroyed because of the tune up, vs because the block was stock..

but if you were to start a build from scratch and wanted over 700hp and over 7000rpm, dont waste your time correcting a stock block. The extra $1k is worth it.

[mt-engines]

Would a 600 hp 434 last a few yrs bracket racing at 12-1 compression shifting at 6400 rpm. Using a scat crank and rods. will be run on E85 only

Yes, if your tune up is on, the problem with the e-85 and stock blocks is they wear the bores pretty bad over time with even a great tune up. You can get away with more compression if you'd like also.

[miniv8]

Would a 600 hp 434 last a few yrs bracket racing at 12-1 compression shifting at 6400 rpm. Using a scat crank and rods. will be run on E85 only

Yes.
Do not tighten the heads more than GM specs, ever.

[rustbucket79]

A 434 might last a few years in a stock block, or it might not. I’ve had great success with some, disappointment with others. (Split cap/fretting/ugly main bearings/various cracks where there were none prior)

For the price of the entire build, why not buy a SHP block and get years of life with better material, thicker bores, better main caps, and less grinding for clearance. It’ll seal a head gasket, not split a head bolt hole, and more importantly, the bores seal much better. You get a block with many rebuilds in it, not investing a bunch of machine work into the block’s last build.

Think about it.

[ProPower engines]

I have done a few for unlimited circle track class's and by the time you clean and mag check the block and add steel caps then correct the cam tunnel and lifter bores as well as bore and deck the block you have spent more then an SHP block does with money left over.

Some guys will do it over time cause they can't put the spare change away for a block which seems like more often then not but.................

[GARY C]

Would a 600 hp 434 last a few yrs bracket racing at 12-1 compression shifting at 6400 rpm. Using a scat crank and rods. will be run on E85 only

Cylinder wall thickness would be the main issue, I had one friend that ran both a 421 and a 434 around 675 hp na and 175 to 300 hp of nitrous and never broke one, we ran a lot of stock blocks from 377, 400, 421 and 434 most never broke and others never made it through the burn out box.

If you can sonic ck the block and be sure it has thick walls then you should be safe but if not you can spend $700.00 or better on one that breaks the first time out... I did it twice.

[rustbucket79]

FWIW GM decided to save a few bucks and retain the open head bolt holes in the 400 blocks. They also sculpted cylinder wall material at each of those head bolt holes, so the wall thickness in those 5 areas is pretty damn thin, under 1/8”. The Dart block does not suffer from this design flaw.

[mt-engines]

FWIW GM decided to save a few bucks and retain the open head bolt holes in the 400 blocks. They also sculpted cylinder wall material at each of those head bolt holes, so the wall thickness in those 5 areas is pretty damn thin, under 1/8”. The Dart block does not suffer from this design flaw.

Design flaw???? Heck if you were to design a 265hp 400 cubic inch engine.. mind you only 265hp and has to be mass produced. would it be beneficial to your company to have .300" cylinder walls, blind bolt holes.. essentially retool everything? No.

The LS engines have some Racing related design problems. But both engines do exactly what they were designed to do.

IM SURE THE OP IS WELL AWARE A DART BLOCK WILL HANDLE MORE POWER. HE ASKED IF 600 HP WILL LAST IN A BRACKET DEAL. THE ANSWER IS YES

[PackardV8]

For an engine shop, the question is piece-work machining or a complete build with our name on it and your tune.

If a bucks-down guy brings in a 400" block and asks for bore, hone, deck, line hone and takes it with him, his decision.

If a guy comes in and says, here's a 400" block, build me a 600hp bracket engine, probably not going there any more.

[rustbucket79]

FWIW GM decided to save a few bucks and retain the open head bolt holes in the 400 blocks. They also sculpted cylinder wall material at each of those head bolt holes, so the wall thickness in those 5 areas is pretty damn thin, under 1/8”. The Dart block does not suffer from this design flaw.

Design flaw???? Heck if you were to design a 265hp 400 cubic inch engine.. mind you only 265hp and has to be mass produced. would it be beneficial to your company to have .300" cylinder walls, blind bolt holes.. essentially retool everything? No.

The LS engines have some Racing related design problems. But both engines do exactly what they were designed to do.

IM SURE THE OP IS WELL AWARE A DART BLOCK WILL HANDLE MORE POWER. HE ASKED IF 600 HP WILL LAST IN A BRACKET DEAL. THE ANSWER IS YES

What is your problem, pal?