Thread:

Made a "little" noise today

Pulled the 342" ( 4.00 x 3.40) out of the Mustang Bonneville car and put it on the dyno. Dad had the build sheet from the guy who owned the car and it seemed like a stought little engine:



The engine needs a little re-fresh as it over-heated 3 times at Bonneville and has a small water leak at a head gasket. We decided to run it to see what it makes for power. On the salt it would only pull 6,300 in 3rd which I thought was 400-500 below peak power.
1988 Mustang Gt went 179.79 on the 5 mile course with this engine ........ 6,300 rpm and 62 psi oil pressure.

Engine specs:

342" ( 4.00" x 3.40")

AFR 205 heads, ported ( no flow numbers...sorry)

12.5:1 Probe pistons, Akerly and Childs rings

Holley HP 750 carb

Edelbrock Vic jr intake ported.

Cam.. solid roller: dur at .050 254/266, .637/.657 lift, 110 lobe sep.

So what's your best guess on power?

Made a couple of pulls then pulled the Holley hP 750 and replaced it will my C&J Engineering modified Demo 750 with a Holley 850 base plate to see what it would do.

Made a total of 7 pulls and was done.... 4 pulls with the Holley and 3 with the demo with a re-jetting.

Best guess ? HP and trq w/ RPM

I'll post dyno results tommorrow night.

S CP

See edit


S CP

Mmmmmmm.......I am guessing.......150 less than a crate 5.3 LS

Originally Posted by gn7

Mmmmmmm.......I am guessing.......150 less than a crate 5.3 LS

bite me.................


S CP

545/66-6700
475/5000-5100

My guess going into this was 525 @ 6,800, 425 lbs ft @ 5,800:

Yesterdays results with the HP 750 with dyno headers 1 3/4":

495Hp at 7,000, 407 lbs ft at 5,900


With modified Demo 750 with an 850 Holley base: C&J Engineering
from 2004

507 hp @ 7,000, 413 lbs ft @ 5,400

Today: With Kooks stepped/merge collector headers 1 3/4 - 1 7/8" Fox body headers

520 hp @ 7,000, 420 lbs ft @ 5,400

engine was making 517 @ 7,200 where we stopped

We made two pulls and were done.. second pull made peak of 518 at 7,000 - 7,200

We did a leak-down after the warm-up

5 cylinders leaking 3%, 2 were leaking 4% and 1 was 5%.

The guy who built the engine in 2005 advertised it as a 500hp 342 long block. This is a happy little engine.

Heads will come off and we will check the bearings and it's ready to run another year.

S CP

Jon

Originally Posted by DEL51

I will guess 509 hp at 7200.

Very good guess for day 1.

Who did you talk to ?


S CP

I thought in the original post Sleeper said it had 12.5 Probe pistons.

Originally Posted by gn7

I thought in the original post Sleeper said it had 12.5 Probe pistons.

I think he's suggesting it's not 12.5:1 as advertised.

I think it is.

S CP

The basics from a couple of pulls:




S CP