71 Cutlass

Then you haven't been reading your own thread. Go back to page one. There was an entire debate about how much horsepower the 350 motors were making "without port work" and other estimations/reasons from car owners. Those HP numbers were taken from the old rating system, and assumed to be applicable for modern day. The only reason the HP discussion began was due to the fact YOU asked to know what "Gains" you would receive from using the BB valves.

Rickman48

Not to start anything, but which Horsepower and Torque numbers do you get from todays Dynos??
I believe gross, as there's nothing hooked to it!
The net numbers for/from todays cars, still aren't what I'd consider 'true', as you've still got a transmission and final drive to get through!
To me, rear-wheel figures are the only 'true' numbers to consider!

Granted, the net numbers are impressive when they get over 400, but what is the true difference - 10, 15, 20%?
Has anyone ever taken the accessories off a late motor to see what the gross difference actually is??
And, as the manufacturers did 'back in the day', are they 'fudging' the numbers?

coppercutlass

I go by the the hp calculator from my 1/4 mile times. I forget about an engine dyno by the time you bolt the trans and add an exhaust and accesories it all changes . To me it's kinda pointless to dyno tune and engine . Chassis dyno yes but that's my opinion. Engine dynos are nice to break in an engine and see what numbers you can achive but it will all change once its in a running car. Unless you have an all out race engine i can agree but for most street engines i dont see a purpose.

Indy_68_S

Oh man, that was back in August !

When talking about older cars like ours, I just consider all HP numbers to be gross or crank numbers unless otherwise stated. To get RWHP I just subtract 20%. May not be completely accurate & prolly overkill, but the drivetrain losses would seem to be rather variable depending on what trans/rear/tire/accessories/etc.. combo is being used in the car.....so 20% oughtta cover it.

Yeah. But 325 HP sounds so much better than 260 !

Indy_68_S

Point taken. Sorry to all if I confused the issue...

Final spec
Car
M-20 4 speed
3.42 anti-spin
PB (will need some vac)
No A/C

stock iron intake
fresh 7028250 Q-jet setup to W-31 specs
shortie headers

#5 heads
2.000/1.625 valves
stock type valve train (new parts)
light bowl work
chambers cc'd 67.5
.030 block
stock crank & rods
3 cc Probes
9.95:1 CR

Jharken

I would keep duration @.050 220 or under with 3.42 gears and use a slow lazy ramp large seat or advertised duration.Peak power should be kept under 5000 rpm in my opinion.

cutlassefi

Then my first choice would be a HiFlow AH, 284/284, 220/220 on a 110 in at 106, lift is .504 on both.
You could go a little bigger with the 9.95:1, but that's your call, but not much bigger as your intake manifold will be your limiting factor. This cam will give you a good tone and a very strong mid range.

Just a little more would be something like 288/288, 223/223 lift is .510, on a 110 also but unless they were side by side you wouldn't see much difference. Again your intake is somewhat limiting. Either way you'll still need to check your spring and retainer to guide specs.

Jmo.

Indy_68_S

Oops...
After seeing jdana24's build thread, I realized I violated 'build thread etiquette' by not posting the final results !

Block (# to car)
Cyl +.030
stock crank & rods
3 cc Probes
mathed out to ~9.92:1 CR

OEM iron intake - no mods
Fresh 7028250 Q-jet setup to W-31 specs

#5 heads
chambers cc'd 67.5
2.000/1.625 valves w/ exh. seats
light bowl/blend work

CompCams 1441 roller rocker kit
Erson lifters
Erson 3175 springs
Erson 220/228 - .504/.504 on a 110 (installed at 109 for dyno)
Cloyes TruRoller
OEM distr w/ points
Stock type coil

Dyno'd at
343Hp @ 5300
376tq @ 3800

Although.... I'm a bit suspect of these numbers. Water temp was down to ~ 125F for the last few pulls. Builder was struggling with the dyno that day. He had a couple of sensor failures that he had to work thru. It was crazy hot/humid outside (105F/99%) and he was concerned that they might be getting some of the bad outside air due to some issues with the cold air supply and monitoring.

Also, due some miscommunication they didn't advance the cam as I wanted when it was built but I didn't realize it until I got the engine home. It was installed @ 109 which was as close to 110 as they could get (full retard on Cloyes). I've since moved it one notch to 107 which is closer to the ideal 106. This should move the power down a bit. I could've gone to 105, but wasn't sure if that was too much... Sooo.."whatever it takes... 107, 106...!"

I guess I'll have to wait until I get the car together and put it on a chassis dyno to find out what the real-world numbers are.....

Thanks to all who helped with info/advice/etc... I do appreciate it.

captjim

Nothing wrong with those numbers for a mild pump gas small block. I'm sure the intake cost you a few ponies. Also, what carb were you using and what was the jet combo? Did you use headers on the dyno?

Indy_68_S

Agreed on intake, but I wanted it to look stock & use my 7028250 with the thermocoil choke.

My bad...left carb info out...
Fresh 7028250 Q-jet setup to W-31 specs by Sparky

I don't know the jet combo.. I'll see if I can find it.
Dyno used some old unknown long tubes that builder had. I'll prolly lose a few with my shorties...

Crappy pic of it on stand... apparently I was seizing or something...

click for big...

jdana24

Thanks for the update. Our builds are very similar, other than our cams are different, and I went with Dave's HEI system (which still looks stock). And our headers are different. I'm sure you will enjoy driving this car.