Newbie here...can anyone shed some light on how a 427 can have this kind of range

C

Coleman Bee

Hi there,

Im still learning...but what is up with this engine?

I thought 427's naturally aspirated top out around 500HP or so...throw in some error if you want to but how is a 2500HP engine possible with the same displacement, and same stroke?

I get that they can vary, but even 2000HP is hard to get to without major engine mods...is there something obvious about the LSX I dont know?

latemodelengines.com

427

This is the absolute proven combination that gives you 2500+ horsepower at your disposal. The solid foundation starts with your choice of blocks; the rigid piece from Dart or direct from GM, with the mighty LSX. Both feature remarkable improvements to the oiling system and cast with exceptional...
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B

Brian Kissel

Staff member
Admin
Lifetime Supporter
That looks to be a long block for a turbo engine. It has top notch components that are designed to handle (up to) 2500hp. Looks like no turbos or intake or fuel system included.

Regards Brian
 
S

Tom

first off, a good 427 can make 600+ hp without anything remotely exotic. Second, as above, the motor you reference is built for boost, and you'll need 60+psi of it to get to 2500 HP. Thus the billet crank, super strong rods, and pistons that are not only strong, but have the top ring lowered from the crown. And also as above, the long block is only the start of the 2500 HP build. A lot of money is going into the supporting hardware.
 
Cobra

Michael

Not that hard to imagine 2500 boosted hp when you consider top fuel engines extract 10k or so from similar cubic inches.
 
manta22

Neil

Supporter
These are apples & oranges comparisons. Sure, tremendous horsepower can be coaxed from engines under the right circumstances but an important consideration is "for how long?".
Top fuel dragsters can exceed 10k horsepower for a 3 second run down a quarter-mile drag strip but it won't live for much longer. Contrast that with a land speed streamliner where the engine is running full throttle for over 5 miles. Two totally different applications with totally different requirements. NASCAR, off-shore boat racing, Le Mans, etc require long-term reliability at high horsepower, not the same as street requirements at all.
 
Howard Jones

Howard Jones

Supporter
I can tell you from experience that 1.5 HP per cubic inch is well within reach on 93 octane pump gas with a 7000 RPM limit. That gets you to 600Hp 400 CI. We held my 400 SBC to 550HP to accommodate the rest of the powertrain limitations. It costs approximately 30 dollars per HP to build with about 50/50 parts cost/labor, machine work, and assembly. Here's the BUT. We used parts selected to be reliable and have longevity for several years of track days, be reusable when rebuilt or refreshed in a couple of years, AND AT THIS POWER LEVEL + approx 10-15%.

It would make no sense to me to build a motor that can make 2500 hp and then finish it to 800hp, and put it in a dual-use or street-only car. Complete waste of money.

On engine building. I have done a few myself (assembly work, no machine work) so I have a good layman's/hotrodder knowledge of what going on. The engine that I had built by Samsons Racing Engines was built as if it was going to be used to run 1-hour long wheel-to-wheel races and stand up to a full season of them. Samson builds SCCA TransAm engines for customers. Every single piece is measured and fitted. Including the completely assembled brand new (ready-to-run) AFR race heads I supplied. All the valves were measured and corrected for length, springs were measured and checked for length, and ft/lbs, heads were surfaced to correct any possible misalignment and then the entire head was reassembled to exactly equal combustion chamber CC's as well as a final re-grind 5 angle valve job. The rest of the engine was done to the same exacting detail. Recheck and fit again until its perfect. The block was a DART SHP iron block that comes ready to machine and it was a lot of work to make perfect. I could go on and on but suffice it to say that if it went into this engine it was measured, weighted, machined, or balanced.

The level of machine work and detailed assembly is a whole other level in a racing engine. Nobody builds a crate motor like that. They could never sell a $18-20K 600 HP crate engine for street car use. So crate engines have a place in the market for sure as do 2500hp capable long blocks. The really important thing is to build the engine to the same spec that it will be used. That's my story and I'm sticking to it.
 
Cobra

Michael

The poster’s question had nothing to do with possible applications, his question was related to the capability of the 427 short block to support up to 2500 hp.
 
Cobra

Michael

Howard, I was just pointing out to Neil that the poster was questioning the capability of the linked short block to produce 2500 hp, not how it was to be used. I chose top fuel motors as an extreme example, just to illustrate that it’s quite possible.
 
C

Coleman Bee

Howard Jones said:
I can tell you from experience that 1.5 HP per cubic inch is well within reach on 93 octane pump gas with a 7000 RPM limit. That gets you to 600Hp 400 CI. We held my 400 SBC to 550HP to accommodate the rest of the powertrain limitations. It costs approximately 30 dollars per HP to build with about 50/50 parts cost/labor, machine work, and assembly. Here's the BUT. We used parts selected to be reliable and have longevity for several years of track days, be reusable when rebuilt or refreshed in a couple of years, AND AT THIS POWER LEVEL + approx 10-15%.

It would make no sense to me to build a motor that can make 2500 hp and then finish it to 800hp, and put it in a dual-use or street-only car. Complete waste of money.

On engine building. I have done a few myself (assembly work, no machine work) so I have a good layman's/hotrodder knowledge of what going on. The engine that I had built by Samsons Racing Engines was built as if it was going to be used to run 1-hour long wheel-to-wheel races and stand up to a full season of them. Samson builds SCCA TransAm engines for customers. Every single piece is measured and fitted. Including the completely assembled brand new (ready-to-run) AFR race heads I supplied. All the valves were measured and corrected for length, springs were measured and checked for length, and ft/lbs, heads were surfaced to correct any possible misalignment and then the entire head was reassembled to exactly equal combustion chamber CC's as well as a final re-grind 5 angle valve job. The rest of the engine was done to the same exacting detail. Recheck and fit again until its perfect. The block was a DART SHP iron block that comes ready to machine and it was a lot of work to make perfect. I could go on and on but suffice it to say that if it went into this engine it was measured, weighted, machined, or balanced.

The level of machine work and detailed assembly is a whole other level in a racing engine. Nobody builds a crate motor like that. They could never sell a $18-20K 600 HP crate engine for street car use. So crate engines have a place in the market for sure as do 2500hp capable long blocks. The really important thing is to build the engine to the same spec that it will be used. That's my story and I'm sticking to it.
Click to expand...
Thank you for this Howard, Im new here but I appreciate how much you put into every conversation you have.
 
C

Coleman Bee

Cobra said:
The poster’s question had nothing to do with possible applications, his question was related to the capability of the 427 short block to support up to 2500 hp.
Click to expand...
I see my mistake. I plan to buy a couple of guides on forced induction engine design so I can really grasp...just how shortsighted I was in posting this lol
 
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