99_pewterZ_A4

iTrader: (1)

From wat I heard I guy from another country had destroked an ls1 dramatically and ended up with 450+rwhp tq-unknown...

Somethin like a 303ci when he got done.

The mad part about this is that he reported peak power at 11,500-12,000rpm!

Any info would be great to know about this, and im sure its an exciting topic to talk about!

w3s1c0a5t

iTrader: (3)

I would believe it could be done. Ever see Vt's NA fox body? Like mid 9's running it to 9500 rpm. I think some of what you heard may be a little outlandish but, I certainly think its is possible.

C5_Pete

iTrader: (8)

With such a short stroke, there is less mass swinging around so higher RPMs are possible. There are no Tq numbers because they are embarassingly small.

99_pewterZ_A4

iTrader: (1)

It reminds me of how indy car v8's are built.

99_pewterZ_A4

iTrader: (1)

And no I havent heard of Vt's fox body.

Old SStroker

Why bother with 11-12,000 rpm (which I doubt anyway due to valvetrain problems), when a 5.0L(305) Daytona Prototype LS engine with the stock truck intake makes more rwhp than 450...lots more, at 7000 max rpm.

The DP engines have the 3.90 bore + a little and a stroke about 3.185.

11,500? Nah!

Jon

01ssreda4

iTrader: (96)

goes along with the one i heard about "some guy" that ran power tour that made 1000 hp on a stock 4th gen corvette (yeah TPI) with only computer work done. give me a break.....

w3s1c0a5t

iTrader: (3)

Search for VT foxbody. And they used motorcycle springs. Like i siad 11-12k may be out of the questions but a destroked motor that makes good hp and revs to the moon is not. Its just not common practice. Mustang guys have to be more creative to make NA power. We just add high lift and more cubes.... Either way maybe not to the level OP is talking about but in the realm of possiblty.

sundaydriver

Ever see a Nascar race at Pocono before the gear change rule 2 years ago.

Motors running 10,200 rpm on the front stretch all day w/ 358ci.

It's all in that 25K valve train.

Tom@SpeedInc

iTrader: (5)

LS motor oil pump spinning same speed as crankshaft, so unless you have altered that I don't see going past 8000 rpm. SBC oil pump is 1/2 speed of the crankshaft.

racer7088

Destroking will certainly move your powerband up in rpm all else equal but the valvetrain will only work at the rpm it can handle reguardless of whether the heads and cam can go higher or not on that destroked shortblock.

Probably not the best idea for a "regular street car" engine of any kind...but hey, if you want less power at a higher rpm go for it!

PowerShift408

iTrader: (44)

Joe Honeycut's car turned 9800 rpm and it's a 370. Apparently there are some very trick valvetrain parts in there, not sure what though so I won't speculate.

racer7088

It spins a little higher than that but its a 4.000 crank in there as well so its a 402 not a 370. It's also only a 4.005 bore not 4.030. You are right that it is valvetrain and nothing else that make that engine spin 10K. There's not many "shelf" parts in that valvetrain of course.

w3s1c0a5t

iTrader: (3)

What makes you think it will be less power? Their are plenty examples of NASTY cars that have done this and i doubt they went thru the Work on the valvetrain to make "less power at higher rpms". Did you think they just get off on hearing their motor wind up? Im sure im going to get ay"stfu you silly kids and all your EFI. We did it in my day with A Big ole carb and double pumper heads" speech. Regardless The answer to the OP is yes. And people have made it work wonderfully.

PowerShift408

iTrader: (44)

Not saying that there are not cars that make great power after being destroked, but any car will make more power with more displacement, with all other variables being the same.

racer7088

You simply do not make more power by destroking. Wouldn't want people to mistake that as a "hidden" way to find power as it isn't.

In heads up racing you can only build an engine so big or you will get disqualified but can always run as small an engine as you want in say any heads up class but of course no one does as they won't get a weight break so they will just turn more rpm and slow down. Sometimes they can't turn anymore rpm so they slow way down.

There's other classes where you can take weight off your car faster than you are losing hp so a smaller destroked engine will be better since you will lose more weight than power and your hp/weight ratio will improve and so will your times. On street vehicles you don't have to add weight when you run a larger engine so it's a no brainer if you want to go faster.

smokinponcho73

iTrader: (6)

Besides there is that old saying There is no replacement for displacement. Take a stock cubed 346 LS and take the power numbers from that, now bore and stroke it to a 408 with stock heads and cam you will almost guranteed to see a power increase unless you have a bad tune or something

mike13

iTrader: (27)

I can believe it and here's my logic. There are alot of high dollar roadracing classes that restrict engine size and weight but not horsepower. I can see a class limit of 305CI and an aluminum motor with the breathing and valvetrain capability of the LSX engines being appealing. In 1983 Jack Roush was making 450rwhp with a Boss 302 and 780cfm carb.

Destroking doesn't make power but it allows you to use a head and valvetrain engineered for much larger motors.

There is alot more money being spent outside the U.S on roadracing, look at the touring car classes the factories back.

racer7088

yes destroking an engine will result in more hp per inch for sure. Not arguing that at all. It works.

poconojoe

iTrader: (43)

Hey if you're going to pick on us old timers with our true old time time SBC's, get the terminolgy correct, it's double hump or camel hump heads, not double pumper heads. No wonder you kids never get it to run right. Short stroke motors will always get more HP per cubic inch. Look at the chevy 302, conservitly rated at 290 HP (actual closer to 350)out of the box, with a single 4 barrel and flat tappet cam, plus with a little work, they produced around 450 HP, NA and without nitrious.