• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Motor on dyno today


FBBO Gold Member
FBBO Gold Member
Local time
2:32 AM
Dec 23, 2016
Reaction score
Channahon IL.
Started my ‘71 RR 383 today.Original numbers matching motor all fresh +.040 all stock except cam. 474-474 comp cams cam. Steel shim .020 Head gaskets stock original heads,used db4b intake and 650 Holley.All broke in late this afternoon,fresh oil and filter.Going to do some pulls in the morning.Hope it makes 300hp. I will try to
Post results tomorrow.Never had a motor I built dynoed!!! Hope it lives (lol)
Is this a contest?
Without knowing piston specs/"stock heads"
I'll guess:
367 hp @ 5000*
470 ft lb @ 3200*

*assumes a properly tuned setup has been accomplished.
*High Performance applications will void your warranty
*these results are for reference only, not everyone can expect these results
*see dealer for details, but all Performance engines must be painted orange


Would really hear the results & few more motor specs. Would sure like to know head cc's, deck height.
Cool! It's nice to have proof on paper huh!
That must be the flattest torque curve I have ever seen. I used to drive my parents new 1971 Road Runner 383 auto (3.23 open rear) to high school in 1971-1973. It had a factory Holley carburetor with vacuum secondaries. Stock with G60-15 tires it ran very low 15 second ET's. Only modification were the thrush straight through mufflers. Thanks for sharing.
Thanks should be a great driver motor.Had a PM that told me the motor was sick because “advertised” hp was 330. O.K here is the deal on that.In the late 70’s early80’s I had a bad *** bass boat.Worked as a promotional man for Champion Boat ,16’8” with a 225hp Mercury 79–80 ALL DAY LONG. SOOO THIS IS LONG BEFORE GPS.Every suntanned big mouth car motor jet boat owner went 100+++ But they could not pass me!!! So we bought this. DYNO or RADAR GUN. (Now gps)I had to dig around in the shop to find this antique!!!!

CCDE7BD4-CBB3-4D90-BD06-DA7543F2971D.jpeg 584C6403-3628-4A84-85A3-7964E13266BA.jpeg
So when the hell is your lazy *** gonna drop it in......?

Gawd,, you old peeps are slow as feces.....

Or do I haffa come do it myself...
Xenon this is not a Hemi so you are UNDER quifiled to put your elephant motor trained hands on this powerhouse that I am putting in my ride!!! Now if you fix the drain plug on the PowerWagon and haul “ROB” over to the shop then you can help with the installation.
Good job! Always a little nerve racking when they open the throttle the first time.
The factory '71 383 was low compression and rated 300 HP gross. What is the compression on this dyno build?
The compression was righ at 8.5-1. All stock except the cam,intake and carb.Looks like these extreme mods I made were worth about 3 hp. (Lol) Now I have to get it. In the car and enjoy it.
It's nice to see the workhorse 383 get some well-deserved attention once in awhile. Probably just me, but I tire of seeing all the 440 Road Runners when no such animal even existed from the factory (I know, except the six pack and later "GTX" options). Long live the 383!