just had the 393 dyno tuned.

[sicaz66]

had my new 393 stroker dyno tuned. hers the specs:
69` 351w block
scat 9000 crank
stock 351 rods
KB hyper pistons
crane cam :dur 216 IN 228 EX, 484IN 512EX @.50, LOBE CENTER 112
performer RPM intake
670 truck avenger
edelbrock rpm heads
1.6 roller rockers
msd distributor,coil and offroad box
33" tires c4,and 4.11`s put down:260 hp and 310ftpounds to the wheels.all under 5000rpm.not too bad but not as much as had hoped for.

 

[jim71]

It's just never enough, is it?

 

[68ford]

that engine combo sounds like it should turn 6000 pretty easy, if you could and not loose alot of torque(dont think it would) the hp would be alot more, why did you stop at 5000? and whats the compresion ratio?

 

[sicaz66]

that engine combo sounds like it should turn 6000 pretty easy, if you could and not loose alot of torque(dont think it would) the hp would be alot more, why did you stop at 5000? and whats the compresion ratio?

comp. is around 9.7:1 it started dropping off after 5000rpm.

 

[broncnaz]

Wow that just doesnt sound right something has to be wrong there even with a slightly higher loss due to an automatic you should have way better numbers than that. Maybe your torque converter is slipping more than it should.
I just looked up some articles on head tests from a couple of years ago they had a 302 9-1 comp similar cam as yours 212/218 .512except it was a roller Edelbrock performer heads air gap manifold and it pumped out 384 hp(6000) and 364 ft lbs(4300) even with a 20% loss that still works out to about 308 hp and 291 ft lbs. I'm not even going to tell you what the 393 they tested put out with stock heads(E7). But the HP was close to the 302's but the torque was way higher ok ok 461 ft lbs. although thee cam was a lot bigger but these numbers are with stock heads mind you. So it should balance out.

 

[tflack]

I don't care what the numbers say, That thing is a hot rod Jason! It felt like riding in a 5.0 mustang.

 

[74bronc]

that is still a 340 horsepower/400 ft lb torque motor when you factor in parasitic drag. Nothing to shake a stick at. Glad you got it running.

 

[sicaz66]

that is still a 340 horsepower/400 ft lb torque motor when you factor in parasitic drag. Nothing to shake a stick at. Glad you got it running.

this not my 408 my 66`).it`s another rig i picked up recently. %)

 

[iwlbcnu]

Something sounds amiss, what was the air/fuel ratios? That should have not fallen off til 5800 at least, and I would think 340-360 rwhp. What is the dizzy set up for total timing?

I do know that I get more rwhp w/ street tires than with ET Streets due to the soft side wall, so the 33's may have hurt you some. I know apples to oranges, but my 306 w/ a little more cam, RPM heads, Performer RPM intake and 650 DP makes 307/307 to the wheels.

Not trying to knock it, just something you may want to look into.

 

[74bronc]

this not my 408 my 66`).it`s another rig i picked up recently. %)

gotcha. another "new rig" huh?

 

[JWMcCrary]

I am building almost the same engine. I am using a little smaller cam. I bought the Comp Cams Xtreme 4X4, 210/218 duration, .477/.493 lift @ .50, 111 lobe separation. Their next size up is almost identical to your Crane cam. Comp Cams recommended the one I bought when I described the rest of my build.

Everything else is almost identical. My block is a 79. I bought the 2.02 valve heads. KB pistons. COmp Cams roller rockers and push rods, same intake and carb, MSD dist, coil, & ignition box.....

Bought B.C. Broncos water pump and a Ron Davis radiator hopefully to help keep it cool.

Just got to find the time to get it all together.

 

[bmc69]

that is still a 340 horsepower/400 ft lb torque motor when you factor in parasitic drag. Nothing to shake a stick at. Glad you got it running.

I was going to guess something like that too..my 408 dynoed on the stand at 342HP and very close to 500 ft-lbs (before the questions start..it's purposely set up for very very high torque at unusually low RPM..hence the apparent 'mismatch' between the peak HP and peak torque). The numbers estimated in the quote above appear to be a very good guess for what the flywheel numbers would be on that 393, based on the rear wheel data. And 260 at the ground is going to motivate the truck..thats for sure.. ;D

 

[Broncobowsher]

For grins, follow the black lines for my untuned 351. Although less cubes, the ion is 11:1. Sure is fun on the street and drivable offroad. Ignor the dip at the bottom end of the curve, I don't have the accelerator pump programed right and that shows up as a dip that isn't there. These are chassis dyno as well

Next up will be the 330 cube stroker for the Ranger, then I will build a good engine for the Bronco that will finally have some good numbers to it.

 

[tabascom16]

Parasitic loss for an older muscle car may be around 20% but our broncos with a tranfercase and most of us with lift kits and bigger tires will have even more parasitic loss. Something more like 25% to 30% even is probalby more like it. I took those numbers and calculated if 30% loss is 371HP and 442 torque. At 25% 350HP and 413 torque. Your flywheel numbers are probably in that range and from the sound of the rebuild and looking at just engine numbers on the net 30% does not look like a bad guess.

I saw a brand new 2001 or so GT mustang on a rear wheel dyno. At its best it put out 210HP and is rated at 260HP. That is a 21% parasitic loss. You know your Bronco is going to have to be worse than that.

 

[76Broncofromhell]

I think the horsepower loss is due to such a small cam. Come on it's a 393 give it some cam. My Bronco is a lot faster since you rode in it last year Jason. I actually fixed the timing issues with it. I would have gone with at least .500+ lift and over 270 duration on the stroker. I happened to use a 108 lobe center with 308 duration and .534 lift.

If you want horsepower that's the setup to use. It's not too fuel efficient but it gets the job done.


Oh yeah....how much was that dyno test?

 

[72_EB]

Yeah, that's terrible. You better pull it out and send it my way. I'll send you my tired motor and you can try again. Seriously, sounds fun. I'm jealous.

 

[68ford]

hes got pretty high compression, big heads, big intake, decent size cam which i think the rpm heads would compensate for some, i still think that motor should fall into the atleast 1 hp per cubic inch catagory.
hate to say it but gm parts has the 350 with 430hp and 430ft lbs.
what dropped after 5000? torque or hp? like people have been saying those are good numbers to the ground, just think they should be a little higher.

 

[Socal Tom]

I still say roller cams can make a big difference.
Tom

 

[Synds9]

from what he's told me, and from riding in it.. (you gotta see this rig) it's not meant to be a monster.. its meant to be something he can drive around town real nice and still get decent mileage with.. this thing is CLEAN.

 

[sicaz66]

Something sounds amiss, what was the air/fuel ratios? That should have not fallen off til 5800 at least, and I would think 340-360 rwhp. What is the dizzy set up for total timing?

I do know that I get more rwhp w/ street tires than with ET Streets due to the soft side wall, so the 33's may have hurt you some. I know apples to oranges, but my 306 w/ a little more cam, RPM heads, Performer RPM intake and 650 DP makes 307/307 to the wheels.

Not trying to knock it, just something you may want to look into.

i did not build the motor.my choice would have been an air gap intake and a bigger cam.it was supposed to have a 770 truck avenger carb. they spent 2 hrs on it only to find out it to be untunable.(it`s going back to holley).a friend gave me his 670 truck avenger to have it tuned for this motor.