[Jack Peters]

Latest MCR has the final chapter of a 421 trip owner rebuild.

Third to the last paragraph is a real kicker and I quote Ken Crocie.
"Pontiac was never too accurate on their horsepower numbers. While this 421 was rated at 370 hp, it was nowhere near the real horsepower of, say, a 375 hp Mopar 440."

Hmmm...what do you all think?

I have heard that it was just the opposite.
A little confused here.

[Baron Von Zeppelin]

i think i understand what Ken is saying
a stock 66 3x2 421 wouldn't put out as much steam as a stock 70 440 Six Pack
but both were rated similar.

Don't have a clue about a 3x2 421 making 317 hp ?
was that at the wheels perhaps ?

[Jack Peters]

That was the hp on the finished engine. Not rw hp. Westech
Do not remember but think they reduced cr
Not sure of cam, either.
It was a several issue project.

[tom s]

There were no specs to the engine when I read it.would love to have Ken come on a post his thoughts.I have mine.Tom

[goatwgn]

317 hp sounds like an accurate description for rear wheel horsepower.

[tom s]

It was a engine dyno

[Jack Peters]

Specs were in previous editions.
Don't have them available. Maybe someone else does.

[J GLASGO]

If that was at the flywheel,that is a very conservative build to say the least. 317 at the wheels would be uninspiring.

[Don Keefe]

Originally Posted by J GLASGO

If that was at the flywheel,that is a very conservative build to say the least. 317 at the wheels would be uninspiring.

I agree. My supercharged 3800 V-6 put out 301 at the wheels.

[Baron Von Zeppelin]

317 at the flywheel must have been with only the center carb operating.
idunno
weird

[goatwgn]

There was a show on Speed network a few years back where they ran a 421 against a 409, and the 421 smoked the 409. It was the 405 hp 421-2x4 bbl. MCR has screwed up too much stuff all ready on that 421 build anyways. It is bad press for the 421 IMO.

[tom s]

Don,remember when you did the article on the all alu debored 389,366 CI?1.80 intake valve with a 2801 summit.It made 318 HP!Tom

[Jack Peters]

Baron. He was talking about a 440/4bbl.

[b-man]

Here's a 1965 389 GTO Tri-Power dyno test article written by Dan Jensen, scroll to page 24 to see the article:

http://editions.amospublishing.com/M...spx?d=20100701

This 10:1 compression 389 bored +.060 over made 338.8 HP @ 5200 RPM and 400.6 LB/FT of torque @ 3600 RPM with the 3 factory air cleaners in place, compared to the factory ratings of 360 HP and 424 LB/FT.

Not too sure if the GTO 389s actually had a true 10.75:1 compression ratio as built, likely closer to 10:1 compression I would suspect. Still I think this particular dyno test was a fairly accurate representation of what these engines were capable of, this one being equipped with the factory issue 068 cam and log exhaust manifolds.

I hope the 1964 370 HP 421 HO I'm gathering parts for right now ends up making similar numbers, hoping to be around 350 HP but anything close is fine by me. I'll be down at around 9.3:1 compression using forged dished pistons to run on 91 octane, using the 068 cam and log exhaust manifolds as well.

Having 300 HP at the wheels would put most 3600 pound cars with decent traction in the mid to low 13s pretty easily using around a 3.23 gear, a pretty fun ride in my book.

I would agree a 317 HP 421 is a bit weak, but not too far off for a stock build with reduced compression.

[Jack Peters]

You need to find back issues or MCR and see what "mild roller" cam they used.
CR was about the same as you expect
It may be that by reading them you can pick up information that will be important to your build.
I think it started with the May 2014 issue.

[Held for Ransom]

Engine is going into a '64 Catalina, being used as a boulevard cruiser. Cam is a Comp Cams mild hydraulic roller. Racetec full floating pistons. 092 heads.

[pontiacs-r-us]

I think some of this engine was discussed in earlier thread? I remember some discussion about the #092 heads,they printed that they were 66' GTO heads in the article.When reading these #'s last week I was very Surprised!!!


Sent from my iPod touch using Tapatalk

[65WJ]

I actually received an amail from them after I pointed out the 4bolt main mistake and then the head casting mistake.
Lots of errors.
The response said his source was incorrect and he thanked me for the correction.

patrick

[KEN CROCIE]

The Mopar part of the quote was not from me. The Owner wanted an engine that was reliable and not fussy in the Nevada desert heat, and run similar to the way the car would have run in the 60s. I'm waiting for a call from the engine builder to verify some of the specs.
I tried to find the article(s) on line , but no luck. Anyone have a link?

[b-man]

Parts 1 through 5, I couldn't dig up the final Part 6.

http://www.hotrod.com/muscle_car_rev...lvage_to_dyno/

http://www.hotrod.com/muscle_car_rev...lvage_to_dyno/

http://www.hotrod.com/muscle_car_rev...lvage_to_dyno/

http://www.hotrod.com/muscle_car_rev...no_reassembly/

http://www.hotrod.com/muscle_car_rev...o_dyno_part_5/