340 power ??

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Mattmoto441

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So just wondering what y'all think my lil 340 might make for power, I would hope for over 400 at the crank. Just freshened it up an here are the specs

340 .60 over 10.2.1 (Whatever compression was in 69)
Out of the box edlebrock aluminium heads
Edlebrock rpm air gap intake
750dp
20200709_014553.jpg

Comp cam
Intake Duration at 050 inch Lift:240
Exhaust Duration at 050 inch Lift:246
Duration at 050 inch Lift:240 int./246 exh.
Advertised Intake Duration:284
Advertised Exhaust Duration:296
Advertised Duration:284 int./296 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.507 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.510 in.
Valve Lift with Factory Rocker Arm Ratio:0.507 int./0.510 exh.
Lobe Separation (degrees):110
 
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325 - 350 hp
Open Chamber aluminum heads

Better get it on the Dyno so you can let us know.
 
It'll be enough to paint black lines on the road and put a smile on your face. Ain't that enough?
 
I’m thinking something north of 400 flywheel horsepower ! So probably what post #2 said 325 to 350 horsepower at the tire !! Maybe more maybe less ! In that ball park !
 
30B86E9E-6634-46F1-8AE7-8575BCAE7DD8.png


This a 5.9l magnum before/after
The before is stock long block and with 4bbl and headers the after Mod is eddy heads comp 275 roller and AirGap 750.
 
Edelbrock advertises there rpm package @ 417 hp. There cam was underwhelming. I’d guess 430/435 hp if you have a 1-3/4 header and you have good tight quench.

The 340 I just finished last week is your build except the cam is a XE285HL w/1-5/8 headers into a 2-1/2 Summit exhaust system. KB slugs set at zero deck w/an .018 dome.
 
i can tel you what mine made with alu open chamber heads and 10.5 compression , flat top pistons zerodeck made 390 hp@6200 rpm 425 tq @ 4600 , i then cut the heads 60 thou compression up to 11.4 not sure the hp then as never tested it after cutting the heads also put 1.6 rockers . Car sure felt like it had 20-30 more hp . hope you make 400 hp you should be able to hit the mark
 
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Here is how it sounded pre rebuilding with a smaller cam

3in flomaster fx vs open headers

 
68-71 340 with X heads, XE268H, headers, air gap and 750 will make darn close to 340-350 HP.

This should make close to 400 is my guess with a solid tune and carb. Stock piston 340, OOTB edes, XS282S cam, victor, 750 made 440-450ish IIRC.
 
Hmm I know another guy that has the same heads but used the eddy cam on a 408 an 9.5.1 and his made 365 to the wheels . So I guess we shall see how this does
 
The power should continue to rise until the valvetrain gets unhappy....... which will very likely happen before the rest of the combo gets “used up”.

If it were a similarly sized solid cam it would easily peak over 6000.
Hydraulic lifters?
You’re at the mercy of the lifters.

You’ll notice on the HR test with the magnum heads it died at 5800.
It didn’t “fall off”...... it nosed over...... hard.
 
Everything that hr does on Westech’s dyno shows big numbers.

Put it in a car and show us the weight, et and mph.


Almost all of the hundreds of engine build I've seen and read been probably at Westech, same with most people without their own dyno, so when most are thinking they want 300 or 400 or 500 hp etc.. their probably thinking in Westech HP, so if real world it less it really don't matter if it's a 450 hp to 90% of the world and a 400 hp engine to the rest. Plus a drag strip only you how much power your using, if you got 600 hp but only turning times of a 450 hp engine it's not telling you how much hp you got only how poorly setup your car is.
 
325 - 350 hp
Open Chamber aluminum heads

Better get it on the Dyno so you can let us know.
cut them 60 thou you have closed chamber no ? at least that is what I did , made a difference engine felt better all around . no idea why i bought the open chamber heads guess they list it as stock replacement for a 340. I called them and they said cut them down no problem
 
So just wondering what y'all think my lil 340 might make for power, I would hope for over 400 at the crank. Just freshened it up an here are the specs

340 .60 over 10.2.1 (Whatever compression was in 69)
Out of the box edlebrock aluminium heads
Edlebrock rpm air gap intake
750dpView attachment 1715558954
Comp cam
Intake Duration at 050 inch Lift:240
Exhaust Duration at 050 inch Lift:246
Duration at 050 inch Lift:240 int./246 exh.
Advertised Intake Duration:284
Advertised Exhaust Duration:296
Advertised Duration:284 int./296 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.507 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.510 in.
Valve Lift with Factory Rocker Arm Ratio:0.507 int./0.510 exh.
Lobe Separation (degrees):110

Matt, are those Edelbrock heads the open or closed chambered heads? Also what pistons are in the engine now?

Open Chamber aluminum heads .
Is that a fact? I can’t read the numbers on the cylinder head.

cut them 60 thou you have closed chamber no?
That’s if he has the open chambered heads.
 
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