~450hp from stock stroke 340?

-
pittsburghracer said:
Tim takes a vacation once in awhile and the guy that fills in is not only nicer, but better looking too.
Click to expand...
I haven't met him yet, I wonder if this guy is the wife's boyfriend he is always talking about, as long as the guy ain't messing with the dyno :lol:
 
273 said:
You can build hp with various ratios of basically duration to head flow, look at LS engines they build 450 hp with 218° cams, say OP hits his goal with his 230° cam as long he has decent gears and stall to go along with it shouldn't be fine.
Click to expand...


No disrespect,,,,but the LS engine is a whole different animal .
That’s apples and oranges to a small block Mopar .

Those cathedral ports are nothing like a Mopar head,,,,,and are not a fair comparison .

I do believe that the start of a happy result for the 340 would be to go higher with the compression .
And I mean a true real compression,,,not a calculation of what it theoretically is .
A few CCs here and there can easily lower the real value a quarter point or more .
When people think they are running 10.5,,,they really only have about 10 to 1 .

Back in 69 when Chevy put out the 302,,,,that was a bad little dude .
And those pistons were ever so slightly short of 11 to 1 .
Heavy TRW pistons they were,,,,,but it was an evil little engine,,,in the right hands .

If Mopar had done that to the 340 in a beautiful little Dart,,,,,man,,,,you talk about some embarrassing times for Chevy and Ford .

A 68 or 69 Dart,,,with a 340 with 11 to 1,,,,solid cam with high .480-.490 lift.,,,,X heads,,,,good aluminum intake.
Then,, in front of an A833 4 speed and an 8 3/4 with 3.91 suregrip,,,,and super stock springs .

Oh yeah,,,,,,wild times for sure !
And that car would have sold,,,,,it would have been a contender for the win every time .

Ohh wellll .

That never happened,,,but I believe it is still possible to replicate .

Tommy
 
Desoto291hemi said:
No disrespect,,,,but the LS engine is a whole different animal .
That’s apples and oranges to a small block Mopar .

Those cathedral ports are nothing like a Mopar head,,,,,and are not a fair comparison .
Click to expand...
Never said it was, but the basic principles are the same, a better head will generally need less cam to make similar power and out of everything cam plays one of the biggest role in driveability, so generally if looking for streetability building hp with head flow over duration gonna give better results was my point.
 
Desoto291hemi said:
No disrespect,,,,but the LS engine is a whole different animal .
That’s apples and oranges to a small block Mopar .

Those cathedral ports are nothing like a Mopar head,,,,,and are not a fair comparison .

I do believe that the start of a happy result for the 340 would be to go higher with the compression .
And I mean a true real compression,,,not a calculation of what it theoretically is .
A few CCs here and there can easily lower the real value a quarter point or more .
When people think they are running 10.5,,,they really only have about 10 to 1 .

Back in 69 when Chevy put out the 302,,,,that was a bad little dude .
And those pistons were ever so slightly short of 11 to 1 .
Heavy TRW pistons they were,,,,,but it was an evil little engine,,,in the right hands .

If Mopar had done that to the 340 in a beautiful little Dart,,,,,man,,,,you talk about some embarrassing times for Chevy and Ford .

A 68 or 69 Dart,,,with a 340 with 11 to 1,,,,solid cam with high .480-.490 lift.,,,,X heads,,,,good aluminum intake.
Then,, in front of an A833 4 speed and an 8 3/4 with 3.91 suregrip,,,,and super stock springs .

Oh yeah,,,,,,wild times for sure !
And that car would have sold,,,,,it would have been a contender for the win every time .

Ohh wellll .

That never happened,,,but I believe it is still possible to replicate .

Tommy
Click to expand...

The night I ate up a 69 Camaro with a 302 in it I enjoyed every bite. Especially when the local Chevy builder told everyone I was dead meat. Lol. Beautiful car and I don’t remember ever seeing or hearing about it again other than how pissed off he was. Funny thing is my property borders the family farm so I kinda hope he can hear me loading up to go racing.
 
pittsburghracer said:
The night I ate up a 69 Camaro with a 302 in it I enjoyed every bite. Especially when the local Chevy builder told everyone I was dead meat. Lol. Beautiful car and I don’t remember ever seeing or hearing about it again other than how pissed off he was. Funny thing is my property borders the family farm so I kinda hope he can hear me loading up to go racing.
Click to expand...
Eat that Chevy boy!
 
The OP can get to his goal pretty easy with a 415.
 
He might need to do something with that "3.91 posi" to make it work though. :poke: :lol:
 
Desoto291hemi said:
No disrespect,,,,but the LS engine is a whole different animal .
That’s apples and oranges to a small block Mopar .

Those cathedral ports are nothing like a Mopar head,,,,,and are not a fair comparison .

I do believe that the start of a happy result for the 340 would be to go higher with the compression .
And I mean a true real compression,,,not a calculation of what it theoretically is .
A few CCs here and there can easily lower the real value a quarter point or more .
When people think they are running 10.5,,,they really only have about 10 to 1 .

Back in 69 when Chevy put out the 302,,,,that was a bad little dude .
And those pistons were ever so slightly short of 11 to 1 .
Heavy TRW pistons they were,,,,,but it was an evil little engine,,,in the right hands .

If Mopar had done that to the 340 in a beautiful little Dart,,,,,man,,,,you talk about some embarrassing times for Chevy and Ford .

A 68 or 69 Dart,,,with a 340 with 11 to 1,,,,solid cam with high .480-.490 lift.,,,,X heads,,,,good aluminum intake.
Then,, in front of an A833 4 speed and an 8 3/4 with 3.91 suregrip,,,,and super stock springs .

Oh yeah,,,,,,wild times for sure !
And that car would have sold,,,,,it would have been a contender for the win every time .

Ohh wellll .

That never happened,,,but I believe it is still possible to replicate .

Tommy
Click to expand...

The 302 came out in 67, not 69
 
B3422w5 said:
The 302 came out in 67, not 69
Click to expand...
My best friend in high school had a 67 Z28 with a 302 4spd 4.56 , that car would rev to the moon, did fairly well for what it was.
But no match for my 67 fastback with 383 torqueflite 4.57 .
 
fishmens67 said:
My best friend in high school had a 67 Z28 with a 302 4spd 4.56 , that car would rev to the moon, did fairly well for what it was.
But no match for my 67 fastback with 383 torqueflite 4.57 .
Click to expand...

Didn’t make many 67 Z’s(602 I think) they are worth serious bread.
 
pittsburghracer said:
I didn’t recommend KB pistons I just grabbed the very first post in the 11.20 area to show how easy 450 horsepower is to make. Unported Edelbrock heads too that flow 255-260cfm compared to 300
Click to expand...

I never mentioned you making a reference to KB pistons. I got that information from the OP's very first post #1

Tom
 
fishmens67 said:
My best friend in high school had a 67 Z28 with a 302 4spd 4.56 , that car would rev to the moon, did fairly well for what it was.
But no match for my 67 fastback with 383 torqueflite 4.57 .
Click to expand...
i have a client with a 67 RS Z28 302/4spd, which i understand is crazy rare. it's a super time capsule and a really cool car. total day two with keystone kustomags, lake wood slappers and hooker's. i don't know if it came with 4.11's or the PO did them along with the other stuff, but it was a serious piece. the guy had me swap in some 3.55's so he could drive it and enjoy it a little more.

but to your point, that thing loves some gear. so much fun to twist its tail and just let it sing.
 
That requires at least 1.32 HP per cubic inch, and while achieving that is possible, it's not going to have street manners. I suppose it's all relative to what you call street manners.

Build a 416" and you only need to make 1.08 HP per cubic inch.
Click to expand...

Totally agree.
And that’s coming from someone who had a 450hp 340 in my car.

When you’re looking for power and civility…….cubes are your friend.

If one is determined to keep the stock stroke, my suggestion would be to more or less ignore the hp goal, and just build the engine using a selection of parts that make sense for how the vehicle will be used……. And then the hp will just be what it is.
Might be 450hp…….. might not.
 
Last edited:
273 said:
The 380hp crate engine makes 400 hp with similar cam and stock magnum heads, don't sound like 450 hp with Trick Flow is that much of s stretch. What's the cr gonna be ?

Here's a 450 hp stock short block 5.9l with edelbrock heads and similar cam.

https://www.motortrend.com/articles/hrdp-0804-small-block-mopar-engine/
Test NotesBase:Production Mopar 5.9 Magnum long-block with passenger-car oil pan, MSD distributor, Mopar M1 Magnum dual-plane intake, 750 Speed Demon carb, 1-inch open carb spacer, 13/4-inch Hooker Super Comp Headers, LA-series engine timing cover

Modified:Add: Comp XFI hydraulic roller cam lobes 3016/3037, Comp pushrods Comp aluminum rockers, Edelbrock Performer RPM Heads, Mopar M1 single-plane intake

230/236-degree duration at 0.050 Comp custom grind on a 110-degree lobe separation, using Comp's XFI hydraulic roller lobes No. 3016 and No. 3037 on the intake and exhaust,

Dyno ResultsMopar Magnum 360SuperFlow 901 engine dynoSTP correction factorTested at Westech Performance Group

RPMBase TQMod TQBase HPMod HP
3,00039837.31228212
3,200410373250227
3,400419390271253
3,600424402290276
3,800420408304295
4,000412412314314
4,200396420316336
4,400381431319361
4,600362432317378
4,800346434317397
5,000328434312413
5,200298433295429
5,400274426282438
5,600-417-444
5,800-406-448
6,000-361-412
Click to expand...
Aluminum heads are absorbing compression because they’re a heat sink. If your static is 10.5:1 your cam choice should be in the 9.5-10:1 range. The crate motors made power because the came equipped with cast iron heads flowing 25 more cfm than the J head untouched.
 
You must log in or register to reply here.
-

Back
Top