AdsoYo

I've had this engine since 2009 and just never thought to ask before because it's been powerful enough for me. I've been thinking about the car lately though and now I'm curious. Golen's website claims the engine should make 400hp and 460lb/ft. I'm putting down 350hp and 370lb/ft. If you account for 15% drivetrain power loss my motor is actually making 415hp, awesome! The torque falls short at 435 ft/lbs. How could I be 25ft/lbs low? Did someone forget to lengthen the stroke after the boring was finished?

Along with the mods in my sig, I'm still using the stock throttle body with an air foil. Golen recommends a 58mm, electric water pump, and long tubes but would not having those really cost 25ft/lbs while my horse power is actually better than expected?

Here's the dyno sheet:


I thought 383's were supposed to peak early, but I told the tuner to stop at 6000 rpm and the horsepower curve hadn't even started to fall yet! Peak torque was at about 4800-5000 rpm and Golen's site says it should be at 4000. What's going on with this motor?

KW Baraka

What type of porting was done to the heads?
What cam do you have in the engine?

Kinda hard to tell what's wrong with the engine given that you haven't told us anything about the engine except that it's a 383 that you got from Golen 4 years ago.....

Peak power (HP & TQ) have as much (and sometimes more) to do with cam specification than with engine displacement.

BTW.....dyno's almost never give you what the builder states you'll get.....especially once the engine's in the car. Various drivetrain and climatic factors can cause you to dyno higher or lower than expected.

And yes.....not having the 'normal' bolt-on modifications can suppress engine power (HP and TQ) by a significant margin......up to 50 HP and 50 LB/FT in your case.

Finally.....the fact that you are running a manual tranny means that you most likely have a drivetrain loss of less than 15%.

KW

AdsoYo

The head info is in the link in my sig. Sorry forgot to mention the cam: 224/230 @ 0.50". Dyno was done on a 89* day with 85% humidity. Thanks for response.

Injuneer

Dyno should be corrected to SAE or STD conditions, to eliminate the variations due to temperature, humidity and pressure.

KW Baraka

That engine with the CC503 cam is gonna peak out around 6200 RPMs....been there, done that. No reason why the engine can't be rev'ed to about 6700 RPMs.

Golen's 400HP at the crank is kinda low, IMO. With a decent set of ported heads, you should hit about 470HP from the engine....pretty easily.

The 460 LB/FTtorque is a bit high.....again, been there, done that. I'd say that 420-430 LB/FT is much more reasonable.

With the appropriate bolts-ons.....52mm TB, long-tubes and dyno tune.....you could see another 20-40 HP; if you really want to go through the expense.

The above is based on personal experience.....and reports I've received from others with the same general build specs as you.

KW


EDIT: Just saw that you had mid-length headers.....so your power increase with long-tubes will be a bit less than what I'd originally thought. Still.....a 52mm TB at some point in the future will yield additional power.