Rusty's Baseline Dyno Test

[Gregski]

Decided to have my '74 GMC 1500 dyno tested before bolting on any shiny performance bits. Rusty is almost all stock except for a few things.

Specs:
350 V8
4 Speed Manual
4 Barrel Rochester Quadrajet
No AC

Modifications:
LMC Truck 2 1/4 dual exhaust with Turbo Mufflers
A.I.R. Air Injection Reactor System - Delete

Here are the results of the three pulls:

1. 172 HP @ 4100 and 259 Tq @ 2600
2. 183 HP @ 4300 and 264 Tq @ 2900
3. 188 HP @ 4100 and 267 Tq @ 3000

* I am eye balling the RPMs for you

This was my first Dyno Test for any vehicle and cost $80 at a place called Evil Genius Racing in West Sacramento, California. John is a super cool guy, if you are local you may want to check them out.

[cadillac_al]

Nice baseline. Aren't these trucks rated at 185 hp anyway? How many miles on yours? Does it rev or pull past 4100 rpm or is that just where max power was? What gear to they test in? I assume 4th or 1:1 gear.

[Gregski]

Originally Posted by cadillac_al

Aren't these trucks rated at 185 hp anyway?

160 @ 3800 RPM according to the 1974 Light Duty Truck Service Manual, I attribute the additional horse power to the less restrictive dual exhaust and the deletion of the SMOG systems

Originally Posted by cadillac_al

How many miles on yours?

Odometer reads 34,457 so I am guessing 234,457 as it's hard to put on a ton of miles on a farm truck, probably not much highway driving

Originally Posted by cadillac_al

Does it rev or pull past 4100 rpm or is that just where max power was?

Yes it revs passed it, we let off at 4,500 RPM

Originally Posted by cadillac_al

What gear to they test in?

Good question, I don't know I will have to ask.

[y5mgisi]

Good base!

[gramps77]

3 pulls for $80 correct?

[Gregski]

Originally Posted by gramps77

3 pulls for $80 correct?

Yes

[Gregski]

just wanted to share a little trick John did for one of the pulls cause he thought the air cleaner snorkel is too restrictive

I am all about little tricks like that, maybe some of you have seen this done already, but I haven't, yet it is so simple (and yes my air filter is dirty as heck, going to replace it and the air cleaner housing next month)

[motornut]

Originally Posted by Gregski

just wanted to share a little trick John did for one of the pulls cause he thought the air cleaner snorkel is too restrictive

I am all about little tricks like that, maybe some of you have seen this done already, but I haven't, yet it is so simple (and yes my air filter is dirty as heck, going to replace it and the air cleaner housing next month)

some swear they were made to do that "flip".
but no all fit
sounds louder too,I want to make one stocker a dual snorkel

[monte0185]

188hp at the wheels is not bad at all. Remember the old hp and torque specs were done at the flywheel not the wheels.

[Dball]

Originally Posted by monte0185

188hp at the wheels is not bad at all. Remember the old hp and torque specs were done at the flywheel not the wheels.

This is what I was thinking, sounds like a healthy base line for sure.

[slotard]

I'm impressed that it's putting down that much power stock. I ought to dyno mine eventually but with 350/350, 4.10s, and currently 30.5" tires it's no fun on the freeway.

[Corts60]

That's awesome. I need to go have my non-turbo diesel tested so I can have a good laugh.

[77 350 Shorty Wide]

The air filter flip has been around along time. I remember my dad doing it on his '69 El Camino. I did it on my new '77 1/2 ton stepside when I got back then.
If you have a truck with stock exhaust the intake sound when you open it up is far more impressive, especially in the cab.

Happy Holidays and God bless, Terry

[justcuz]

What I have done is take the snorkel off the air cleaner. It is spot welded on. Them I take a piece of cardboard and trace the oval pattern and transfer one to the other side of the air cleaner and one in the back. Then the air cleaner has three large oval holes in it and retains the breather for the crankcase to the rocker cover. On models that have the breather inside the air cleaner base I just cut the entire bottom off of the air cleaner.

[Gregski]

Originally Posted by justcuz

What I have done is take the snorkel off the air cleaner. It is spot welded on. Them I take a piece of cardboard and trace the oval pattern and transfer one to the other side of the air cleaner and one in the back. Then the air cleaner has three large oval holes in it and retains the breather for the crankcase to the rocker cover.

Sounds interesting, do you have any pics?

[justcuz]

Originally Posted by Gregski

Sounds interesting, do you have any pics?

Yes I think I can come up with a couple later today.

[86c20]

nice nubers to start with. but i hope that you dont really think your truck is rusty??? i could show you pix of my c20 and my ramp truck that are on the road and pass inspection that make southners cry lol

[cadillac_al]

This power curve is just perfect for the average driving that I do (now). 90% of my driving is between 2000-3000 rpm and the trans shifts at 4500 at WOT. I have to replace my cam this summer and I hope the aftermarket can supply me with a cam with max efficiency at 2500 rpm.

[MikeB]

Originally Posted by cadillac_al

This power curve is just perfect for the average driving that I do (now). 90% of my driving is between 2000-3000 rpm and the trans shifts at 4500 at WOT. I have to replace my cam this summer and I hope the aftermarket can supply me with a cam with max efficiency at 2500 rpm.

1500-3000 RPM with a max of 4500 (if that much) is where a good driver needs to make power. There are lots of aftermarket cams that will work well for you. The inexpensive Summit Racing SUM-K1101 cam would do the trick, and possibly their K1102 depending on your truck's axle ratio and compression. Some of the newer design cams, like the smallest Lunati Voodoo or Crane Z-series, should work even better.