Shoddy engine builder or am I missing something?

[Paul Boucher]

Bored and stroked 500 cubic inch and making only 363HP? It does say they are your "GM LSX" specialists on the dyno sheet, hahaha! For what this guy is asking and overall quality, or lack there of, this R/T is pig in bad lipstick. I offered him $19.67, hahahah!

https://www.ebay.com/itm/384361538759?mkevt=1&mkpid=0&emsid=e11021.m43.l1120&mkcid=7&ch=osgood&euid=c3efba133b894dea9c8c4d9f7bc5f317&bu=44542381668&ut=RU&exe=99031&ext=233633&osub=-1~1&crd=20210831064111&segname=11021&sojTags=ch=ch,bu=bu,ut=ut,nqt=nqt,nqc=nqc,mdbreftime=mdbreftime,es=es,ec=ec,exe=exe,ext=ext,exe=exe,ext=ext,osub=osub,crd=crd,segname=segname,chnl=mkcid

 

[padam]

It does say chassis hp, so not sure how that compares to flywheel.

 

[440Coronet500]

It does say chassis hp, so not sure how that compares to flywheel.

There's a big difference between rear wheel and flywheel HP/Torque. 440'

 

[ksurfer2]

Powertech Performance is St Pete did the mods to the LS3 in my C6 Corvette (cam, headers, supercharger, meth injection, clutch, tuning, and dyno). Joe, the owner is a great guy and VERY knowledgeable about all things LS. I have seen their operation and they are not a machine shop, nor do they do full engine builds. The engine was likely built elsewhere and dyno'd at Powertech.

 

[moes]

I'm sure they would get more HP/torque out of the motor if it was tuned by someone that knows Mopar motors and what they like.

 

[70bigblockdodge]

If you add in the 20% drivetrain loss it is 435hp. I'm not sure you would be losing 20% through a 8 3/4 and a 727, but that still puts you in ~400hp in the 10-15% drivetrain loss.
A stockish hydraulic automatic from the era seem to have issues on modern dynos. Mostly due to downshifting and lagging trans line pressure as they do a acceleration run. These modern chassis dynos seem to favor electronic controlled automatics and manual transmissions.
I'm no expert just IMO.

 

[R413]

The engine tuner and or whoever chose the parts may have got it wrong. Like a 650 edelbrock carb on a 500 cube engine, or 30 degrees of timing to run regular gas.

They may have done it with a cold engine an 20/50 oil, or straight 50 weight oil. It’s Florida so always hot. People do strange stuf.

Different dynos give different readings, some are jacked up to read high.

 

[slepr1]

I just watched a YouTube video from Nicks Garage about a 520ci stroked 440 that dyno'd at 453hp with headers, then put on stock exhaust manifolds and lost 20hp . Not his build but he fixed a piston slap issue. Engine had stock intake, 440 source aluminum heads, comp cams and stock rockers.

 

[Paul Boucher]

Thanks for the input guys. I really didn't think you would loose that much HP, but I guess I am wrong. That is why I asked. I guess I'll vote myself in the "I completely missed something category".

 

[66Satellite47]

My Satellite with 500" 440 EDE RPM's unmodified, 10.5 real CR, Comp low .500 lift solid, Torker/850 DP did 500 on the engine dyno. So on a chassis dyno that should be about 425. It ran 12.60's with the exhaust. With open headers it improved to 11.80's. Can we say junk exhaust?
When I put in my '70's 560/585 lift Cam Dynamics, it went to 11.20 with open exhaust.

 

[Paul Boucher]

My Satellite with 500" 440 EDE RPM's unmodified, 10.5 real CR, Comp low .500 lift solid, Torker/850 DP did 500 on the engine dyno. So on a chassis dyno that should be about 425. It ran 12.60's with the exhaust. With open headers it improved to 11.80's. Can we say junk exhaust?
When I put in my '70's 560/585 lift Cam Dynamics, it went to 11.20 with open exhaust.

See, that is more in line of what I was thinking. At 363 that would be 62 HP difference and that seems like a lot to me. And for what the guy is asking I feel like that is really a dog of a motor in a lipstick pig. Again I may be missing something, but it just seems out of line to me.

 

[dvw]

Chassis dyno is a tuning tool, nothing more. Real numbers could be anywhere. In pictures it looks like a a pretty decently detailed build. My bet is the motor is the same quality as the car.
Doug

 

[Budnicks]

wrong or mismatched parts, good parts it appears to be
but maybe just wrong combo, or the tune
even if it's at the rear wheels HP
the converter & who's running the car/dyno
can have huge results differences too
what RPMs did it do that ?
did he run it out to it's full potential ?

was that the 1st run or only run on the dyno ?
could be way out of tune
sometimes even something as simple as
a proper air-cleaner can make or break + or - 40hp
dead fat, dead lean or not enough or too much timing etc.
operator error (person running it on the dyno) could be a huge part too

where was this all done ?
who built the engine ?

who chose the parts ?, cam heads induction exhaust etc.

I'll bet it's tuning "issues" or operator errors

that's a pouch for a 500cid stroker,
even the torque is way down

 

[66Satellite47]

In 20 years hard core bracket racing never had a motor on a dyno, I think made pretty good power. Track results were the answer. Lots of guys talked dyno numbers, but....
My Satellite 500" motor did 500 on the engine dyno, I expect it would do 425+ on the chassis dyno. I think it would have been nearly hard to control on the street with a good exhaust.