Dynoed my cheap 383

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Babyblue66

Babyblue66

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In an apartment, MN
Here is an engine I just dynoed. Thought some of you might find it interesting. Put together with mostly used parts I had.
1970 383 with the original cast pistons. Ball honed and new rings. All new bearings.
516 heads I mildly ported and installed used 1.74 exhaust valves. Compression came out to 9.4 to 1.
A serdi valve job and cut the guides for viton seals.
A lightly used Elgin cam with 224 234 @. 050 and 465 488 lift on a 112 LSA. New lifters.
Used Mopar performance valve springs.
I reused the oil pump and double roller timing gears.
Stock intake with a 750 dp and headers it made 380 hp at 5600 and 408 ft lbs at 3500. We didn't start the pull earlier, so it may have made more torque lower. It lost 12 hp with the original AVS, but it was a bit rich.

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Nice, close enough to a HP per Cube for me.
Stock intake?
 
Dang, I'd be curious as to the power output past 5600 RPM! Looks like she wasn't done pullin'....
 
cudavert said:
Dang, I'd be curious as to the power output past 5600 RPM! Looks like she wasn't done pullin'....
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It had a little sputter at 5600. I had a points distributor in it, I'm thinking that was the problem so we just stopped at 5600. On the second pull, my first brand new set of Blue Streak points fell apart. I had to run to a parts store and get more. I won't run points on the dyno again.
 
Stock torque for the HP was 425LBFT so I'd say that's purdy dang good. It'll be hell in an A body.
 
Back in the day I had replaced the stock intake with a DP4B while keeping the AVS. I wonder if there was/is a power increase over the stock manifold
 
Nice job. I'll bet that engine starts pulling way below 3500.
 
I knew 383s/400s were capable of good horsepower, & this proves it. Thanks
 
niceolddart said:
I knew 383s/400s were capable of good horsepower, & this proves it. Thanks
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I was pretty surprised. I built one for a friend last winter. 383, 8.8 to 1, 906 heads with 2.14 1.81 valves, mild bowl port, Comp xe268, made 380 hp and 421 torque. With the stock intake and a 750 quick fuel carb
 
Shouldn't be surprised. It's got a 4.250 bore.
 
Babyblue66 said:
But seems like a very mild build to me, for basically 1 hp per cu in.
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Did you end up with new valve seats to go from the 1.60 to the 1.74 valve..?? I have a pretty comprable build in a 71 swinger 3.91, 4 speed car. Still has 1.60 valves, just curious what the difference might be….Thanks Swingn’
 
Swingn’71 said:
Did you end up with new valve seats to go from the 1.60 to the 1.74 valve..?? I have a pretty comprable build in a 71 swinger 3.91, 4 speed car. Still has 1.60 valves, just curious what the difference might be….Thanks Swingn’
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I cut the seats for the bigger valves using a Serdi. Then did a little porting.
 
RustyRatRod said:
Yeah. They are very under rated. People are pissin all over um in another thread.
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For the most part, there is nothing wrong with an iron head. Some ports are better than others on the various version heads the OEM used. The only real draw back is weight. Followed by what can be corrected, adjusted or modified by machining, which if you can do yourself is a huge home run! 3/8 valves, different valve sizes, spring pockets/seats… etc…
 
Babyblue66 said:
It had a little sputter at 5600. I had a points distributor in it, I'm thinking that was the problem so we just stopped at 5600. On the second pull, my first brand new set of Blue Streak points fell apart. I had to run to a parts store and get more. I won't run points on the dyno again.
Click to expand...
yeah Uncle Tony has said today points are junk...
 
One HP per cube with stock parts and a mild, street friendly cam is very respectable.
 
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