Boss 347 Dyno Results

[c9zx]

Did you record the run? Would love to hear the 7k rpm music!

Way beyond "red" line of many engines. What kind of valve springs do you have on these heads?

Not a great video but it is informational. Chuck

 

[Don C]

Nice !!!

:bravo:

 

[Fabrice]

So you did hit the red zone!

Awesome!

 

[c9zx]

Wow.....so maybe I shouldn't give up my 302 for a 351C.

Would you share the components and specifications that made this thing so "Friskie".

Thank you,

HVY MTL

347 inch 1969 Boss 302, 10:1, SFT cam, Dual plane (Ed 7129), 750 HP carb (80528-2), 1.875 Primary tube 34" long to 3.5 inch collector 10 inches long. 

Crank and rods from Molnar, pistons from Racetec, ATI damper, internal balance. Custom solid flat tappet cam from Jones cams (aggressive for street use), minor porting of 1969 Boss 302 heads Very good valve train components. I have no idea what is going on with the font size. Chuck




   

 

[boilermaster]

C9ZX,

Stop the torture!

There HAS to be an engine build thread on this engine.

There HAS to be an engine build thread on this engine.

Boilermaster

 

[c9zx]

C9ZX,

Stop the torture!

There HAS to be an engine build thread on this engine.

There HAS to be an engine build thread on this engine.

Boilermaster

Here is the short version.

 I used the 302 Boss engine because it goes into a real Boss 302 powered 1969 Cougar Eliminator. The cam (SFT) is very aggressive for a street cam, making it idle reasonably well will likely be a challenge.



Bore is 4.040, stroke 3.400 (forged), rods (I beam) 5.400. Crank and rods from Molnar, pistons are (forged) flat tops from Racetec (10:1 SCR), rings moly top, napier second, medium low tension oil ring  (Total Seal, not gapless, top and second, Hastings oil ring). Quench distance is .036. Lightweight valve train components (hollow stem intake valves, titanium retainers and locks) and (controlling the big intake valve is challenging). Spring pressure is 390 over the nose which will put the seat at about 160 (break in done with inner spring removed). Minor porting of Boss 302 heads in bowls, chamber, and short side, quality 5 angle valve job. .118 wall Smith Brothers pushrods (custom length, optimized geometry). Intake is out of the box Edelbrock 7129. 1 inch open spacer. Carb is Holley 750 HP, 0-80528-2, custom calibrated. Total timing 38 degrees.

The headers were stepped dyno pieces. The in car headers are Hooker 1/78 primaries, 34 long, 3 1/2 collectors 10 inches long. It is likely the torque will go up a little bit and the HP may go down a little bit with the in car headers. Chuck

Boss 302 Head Flow Data.pdf

 

[tony-muscle]

I like to look at these in a line chart. Talk about a flat torque curve.

Amazing... the top torque number doesnt tell the whole story. He is getting 350 (1 to 1 torque/CI) already at 3000 rpm and thats with a very aggresive cam.
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[tony-muscle]

Wow.....so maybe I shouldn't give up my 302 for a 351C.

Would you share the components and specifications that made this thing so "Friskie".

Thank you,

HVY MTL

347 inch 1969 Boss 302, 10:1, SFT cam, Dual plane (Ed 7129), 750 HP carb (80528-2), 1.875 Primary tube 34" long to 3.5 inch collector 10 inches long. 

Crank and rods from Molnar, pistons from Racetec, ATI damper, internal balance. Custom solid flat tappet cam from Jones cams (aggressive for street use), minor porting of 1969 Boss 302 heads Very good valve train components. I have no idea what is going on with the font size. Chuck




   

Mechanical lifters?
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[c9zx]

Wow.....so maybe I shouldn't give up my 302 for a 351C.

Would you share the components and specifications that made this thing so "Friskie".

Thank you,

HVY MTL

347 inch 1969 Boss 302, 10:1, SFT cam, Dual plane (Ed 7129), 750 HP carb (80528-2), 1.875 Primary tube 34" long to 3.5 inch collector 10 inches long. 

Crank and rods from Molnar, pistons from Racetec, ATI damper, internal balance. Custom solid flat tappet cam from Jones cams (aggressive for street use), minor porting of 1969 Boss 302 heads Very good valve train components. I have no idea what is going on with the font size. Chuck




   

Mechanical lifters?

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Yes, solid flat tappet cam and lifters.

 

[TommyK]

347 inch 1969 Boss 302, 10:1, SFT cam, Dual plane (Ed 7129), 750 HP carb (80528-2), 1.875 Primary tube 34" long to 3.5 inch collector 10 inches long. 

Crank and rods from Molnar, pistons from Racetec, ATI damper, internal balance. Custom solid flat tappet cam from Jones cams (aggressive for street use), minor porting of 1969 Boss 302 heads Very good valve train components. I have no idea what is going on with the font size. Chuck




   

Mechanical lifters?

Sent from my SAMSUNG-SM-G930A using Tapatalk

Yes, solid flat tappet cam and lifters.

Not bad for obsolete iron heads ::thumb::

 

[keiths71]

It's cool that you used the solid cam. So are you running 2.25 intakes? Back when I built my Boss I bought all my valvetrain parts from Bill Maier , when he used to sell engine parts. Lots of high rpm use, never an issue. Your more modern combo should be even better.

 

[c9zx]

I'm using a hollow stem 2.25 intake valve because the original valve was 2.23 and I didn't want to replace the seats and there are no 2.23 hollow stem valves available that I know of. I was trying to reduce valve train weight to maintain valve train stability at high RPM. Given the stock bore of 4.000", and the valve angle to the bore, a  2.100" intake valve may be closer to the optimal size to reduce shrouding from the chamber wall and the bore. Chuck

 

[tony-muscle]

I have a silly question about a chasis dyno. Sorry that I go slightly off the tangent, but I am thinking about it while I read this thread. I understand that this was an engine dyno. However, when chasis dynoing, depending on the rear gear ratio, the tires have to move at the equivalent of ~130 to ~160 MPH. Are these high speeds an issue with our rear axles? The speedometer marks up to 120 MPH, can there be an issue with going to 160?

 

[Don C]

I think a bigger issue and concern is tire condition and speed rating. A tire coming apart at high speed can do a lot of damage.

https://www.bing.com/videos/search?q=chassis+dyno+mishaps&view=detail&mid=AE2E9974FB095F491BF6AE2E9974FB095F491BF6&FORM=VRRTAP&vrvid=AE2E9974FB095F491BF6AE2E9974FB095F491BF6&PC=MOZA

 

[EdM]

Nice. I went the torque route in the RPM's I find myself driving with my now removed Cleveland. It should be running in my '73 in a week or so.

 

[mjlan]

Awesome engine!

Got any pics of the car? I’m a sucker for a 69 Cougar...

 

[c9zx]

Awesome engine!

Got any pics of the car? I’m a sucker for a 69 Cougar...

Here you go. Chuck

 

[mjlan]

Awesome!

Thanks