Power limits for LA small blocks?

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clinteg said:
Yep probably not a question that can be easily answered. Wish I had more miles on mine so I could give better feedback on longevity. Motor is probably right around 580-600 hp naturally aspirated and pulls my 3300 lb (race weight) Dart mid 10's in the 1/4. Don't have many miles on the motor yet but they have been tough miles since I'm always giving it hell! Combination of sreet driving and track days. Block has been fine this far and like I said, I haven't been easy on it. It's 7000+ rpm on the regular lol. I also wanted to keep all the interior so I have front buckets, rear bench, 6 pt roll bar with removeable swing outs and rear center bar. This allows easy access for rear seat passengers. Next is an overdrive so the highway miles will be comfortable even with 4.10's. So it's going to be a good street cruiser and decent drag car by the time that's done. But if my block ever fails, I'll post it up.
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This is very similiar to what I wanted to build. Keep me posted as I don't plan on starting this project for a month or two.
 
A friend of mine, have a 454 small block mopar with a R3 block and indy heads,700 over hp, in a 1966 valiant, full body,he run 9.90 ,with the exhausts connected, run on the street, run with the car for 3 years now, the only problem is with the roller lifter shafts
 
Just a $.02 addition... According to a book I got "Maximum Boost" by Corky Bell, what kills engines is RPM not cylinder pressure from extra torque. In other words the inertia forces acting on the block, crank, rods etc. from everything spinning at high RPM puts a lot more stress on the parts than the combustion pressure itself. That's why you see a lot of turbo engines making way more power than they ought to be able to handle; the boost allows them to make more torque (and thus power) at a lower RPM range.
 
My 410 stroker was somewhere north of 500hp (probably 550 ish, but never dynoed). Ran great for 7 years, mid 10's, raced a LOT, no real issues....then broke a rod out of the blue which destroyed the block. The bearings (except for the one on the broken rod) all looked great. It may be ill advised, but I'm rebuilding for about 600hp, and my new ET goal will be low 10's (10.3-10.0).
 
flyfish said:
My 410 stroker was somewhere north of 500hp (probably 550 ish, but never dynoed). Ran great for 7 years, mid 10's, raced a LOT, no real issues....then broke a rod out of the blue which destroyed the block. The bearings (except for the one on the broken rod) all looked great. It may be ill advised, but I'm rebuilding for about 600hp, and my new ET goal will be low 10's (10.3-10.0).
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Your engine is always been one of my favorites. I know you drive that thing a lot and race it a lot. Honestly yours is exactly what I had in mind. Sadly though I am second guessing my big stroker build. If I get up over the 500 hp mark I will likely need to rebuild the 727, I WILL need a new rear end, I will likely need to put some sort of a cage in it so I can run at the track. I could simply give the builder my engine with aluminum heads and flat top pistons and tell him to throw a new cam in it and port out the intake and heads. I can get that stock stroke 360 down into the mid 12s and then use the $2000 I save to put toward finally getting the car painted.
 
doogievlg said:
Your engine is always been one of my favorites. I know you drive that thing a lot and race it a lot. Honestly yours is exactly what I had in mind. Sadly though I am second guessing my big stroker build. If I get up over the 500 hp mark I will likely need to rebuild the 727, I WILL need a new rear end, I will likely need to put some sort of a cage in it so I can run at the track. I could simply give the builder my engine with aluminum heads and flat top pistons and tell him to throw a new cam in it and port out the intake and heads. I can get that stock stroke 360 down into the mid 12s and then use the $2000 I save to put toward finally getting the car painted.
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You should be able to get 360 inches in the mid to high elevens pretty easy. You'll need some gear and a good converter but easily doable.
 
Mid to low 12's?

Zero deck slugs with roller rockers on top of Edelbrock heads and rpm intake, 750 cfm (min.), 1-3/4 headers, 2-1/2 exhaust (min.)
292/.509 MP Hyd. Or a Comp 296S cam. ( Both 248@.050 duration)
Go up 1 cam size and bowl port the heads at a min. And you'll have high 11's.

Proper stall with a shift kit or a killer clutch, 4.10's & 27 inch tires as wide as possible. SS springs and frame connectors.
 
I was originally wanting 11s in a comfortable street car but I am reassessing my goals.
 
Why on Earth would anyone even want 550+ hp on the street?
On a 3200lb A-Body no less!
I know I contributed no help to this conversation, but I had to say it...
Thanks for letting me get that off my chest!

Jeff
 
MrJLR said:
Why on Earth would anyone even want 550+ hp on the street?
On a 3200lb A-Body no less!
I know I contributed no help to this conversation, but I had to say it...
Thanks for letting me get that off my chest!

Jeff
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Well Jeff, it's a lot like the wife asking "Why did you bring that old rusted out junky Plymouth home."

"If I have to explain it to you honey, you just would t understand."

HP junkies all want a little more.
And sorry to say, 550hp ain't all that when you have had it before (last year for example) then next year, it's boring.
 
rumblefish360 said:
Well Jeff, it's a lot like the wife asking "Why did you bring that old rusted out junky Plymouth home."

"If I have to explain it to you honey, you just would t understand."

HP junkies all want a little more.
And sorry to say, 550hp ain't all that when you have had it before (last year for example) then next year, it's boring.
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That's never a fun conversation. It's hard to explain why I need new headers rather than a new lawn mower.
 
yellow rose said:
That's never a fun conversation. It's hard to explain why I need new headers rather than a new lawn mower.
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I'm glad my wife and I never have THE MONEY CONVERSATION. 500 bucks for me, 600 for her, it works !
 
rumblefish360 said:
Well Jeff, it's a lot like the wife asking "Why did you bring that old rusted out junky Plymouth home."

"If I have to explain it to you honey, you just would t understand."

HP junkies all want a little more.
And sorry to say, 550hp ain't all that when you have had it before (last year for example) then next year, it's boring.
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Ya....I guess I can see your point. ....
Maybe I'm a really old 50 year old...lol
Seems like an awful lot for the street though. ...

:steering:

Jeff
 
MrJLR said:
Ya....I guess I can see your point. ....
Maybe I'm a really old 50 year old...lol
Seems like an awful lot for the street though. ...

:steering:

Jeff
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All the cars I've built have an adjustable horsepower switch. That way, you can dial up the power you want.
 
MrJLR said:
Why on Earth would anyone even want 550+ hp on the street?
On a 3200lb A-Body no less!
I know I contributed no help to this conversation, but I had to say it...
Thanks for letting me get that off my chest!

Jeff
Click to expand...

When I was about 18 my friends uncle built a twin turbo car that was pumping out around 2000 hp. He would drive that car up the interstate to local cruise ins at resturants and it blew my mind. Now I have a buddy up the street with a twin turbo LS in a beat up old malibu wagon that is right around 1000 hp.

If I had the money I would build the most powerful well mannered engine I could but because of this post I have learned that with a factory block 600 hp is really pushing it. Instead of satisfying my desire for ungodly power with my little small block I will be keeping my dart as a nice cruiser that I can hop in and take road trips in. One day I will build a big nasty boosted mopar with ungodly amounts of power though.
 
To the OP please visit this site, the guy built a $2200 motor and had his A body in the 11's. He advised me and is a member here when I built my engine.

(no title)
 
MrJLR said:
Ya....I guess I can see your point. ....
Maybe I'm a really old 50 year old...lol
Seems like an awful lot for the street though. ...

:steering:

Jeff
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It is Jeff, it is. But that is also dependent on who is pushing the long pedal down. And what there used to and satisfied with. Along with the purpose of there car.
I have a '14 Challenger V6 SXT
Excellent everyday driver in a cool wrapper. Fast? Naaaaaaaaa

I have a '79 Magnum with a 5.9 Magnum and bolt on parts. No cam, yet, but it will be a very street friendly grind. 727 + mild stall converter & 3.55's. A drive everywhere car with decent road power.

I have a '73/4spd Cuda. (Once I can get back to that...LMAO!) It has been my street strip muscle machine for 30 years now. Low 12, hi 11's on the street and getting faster. Next engine is a stroker 6 pack. If it makes low 11's, so be it.

It have a '71 Duster. Future (80%) strip car. W5/904/4.88's/tub/slicks etc....

I stay in the Challenger as much as possible. It's new, everything works well, OK for power, everything is nice. This makes the other cars exciting when you get in them because not only am I in a old MoPar ride, but there a lot more powerful than the '14 Chally. It helps keep my speed freak in check.

And the wife, she is almost as bad as me. She has her own stock pile of speed parts in the corner.
 
Back to why are the 4 cylinder imports able to make so much power ? Cylinder head design with overhead cams and low reciprocating weight, which equals high RPMs. They make horsepower at 10-12k rpms. Try to do that with a V-8 and keep it together. That is the short and sweet as to why they do what they do. Of course if $$ is no object you can eventually make the power with durability ( wait, what about NASCAR engines )
 
LOL! Good one! I'll say the Jap (and other far easterners) import block is a super sturdy unit totally unnecessarily overbuilt for the street. Take a good look at the block. There designed the way we wish ours were. But that is also progress. Let's stop and think for a second. The A engine was made when? Which means the design is older than the first appearance dates. Then came the LA, which borrowed heavily from the A engine. Similar deal with the B/RB engines.

There design is a simple one with a simple job. Move people.

Rpm isn't necessarily horse power.
Our V8's are low rpm engine that make there power early on.

I do however remember some ultra high reving Italian guys laughing at us until we whipped there *** with our lowly low rpm machines.

Thank you Mr. Shelby!!!!
 
rumblefish360 said:
Rpm isn't necessarily horse power.
Our V8's are low rpm engine that make there power early on.
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Even a lowly stock stroked 360 and 440
Can hit 500hp and 600hp respectively by 5800 rpm, no need to make them scream.
 
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