421 SBC dyno carl posted

[grumpyvette]

421 dyno results
Spent Friday on the dyno testing 421 pump gas build for a customer, He was looking for a 600 horse pump gas build and we achieved our goals with this build. Torque was very impressive @ 574 FT LBS. Tried to build this with all shelf stock parts so it so it could be duplicated. The good thing this is just a street car and only needed to turn this engine 6400 to make peak power.

Little about the build
posted by CARL HINKSON
Dart SHP block 4.155 bore
Callies 3.875 D/S crank
Callies 6 inch rods
Mahle pistons
Clevite V bearings
259/263 Solid Roller 108 Lobe sep .626 lift.
Steffs custom aluminum pan
Bullet S/R roller cam 1.000 base circle cam
.904 Morel lifters
AFR heads 220/75cc chambers ( Thanks Tony Mamo )
061040 World intake
Pro Systems carb
MSD Distributor
ATI balancer
Crower SS rockers 1.5
Mellings 10552 pump

 

[87vette81big]

Hand scetched is 34 degrees BTDC TOTAL TIMING.
2" inch primary Header.

Brake specific fuel consumption numbers look good.
.400 + Range & under .500.
Its making an efficient use of every drop of gasoline -BTU energy content of fuel.

Its a stellar torque curve.
Goood HP.
MADE THE GOAL 600HP +.
Be a long lasting street engine.

Also noted......they Used Vandervell Main & Rod Bearings.
Clevite "V" series reproduction.
My favorite street & strip bearings.
Few use them other than me.
Highly prized by Pontiac guys like me.

 

[87vette81big]

Block lifter bores Resized to .904 Chrysler Hemi Lifter base diameter too.
Old NHRA SUPER STOCK RACER TRICK.
FASTER LIFTER & Valvetrain acceleration rates.
Oldsmobile innovation original.
1965 Olds 425 Starfire V8.
AND 1966-67 425 TORONADO V8 ONLY
.924 DIAMETER LIFTERS USED.

No volumemetric efficiency rates shown.
Must have engine water brake tested without carburator airflow bell velocity stack in place.

My guess 95-98% peak volumemetric effiecency rate at peak engine torque exact.


BRIAN

 

[grumpyvette]

just for grins I ran the posted specs thru a few calculators and put the resulting info into DD2000 to see what it predicted, and yes before you ask, they obviously must use race octane gas

 

[87vette81big]

Lol.
Grumpy proved otherwise Its not pump gas friendly the 421 AFR220.
They could always retard ignition timing to 21 degrees or less total timing.
Power will go south & run terrible on the street.

Todays pump gas is so bad.
Whats sold as 93 R+M/2 gasoline I think actually has a true Motor octane of 85-87.
E10 tainted junk gas.

I would Never go higher than 9.8 to 10:1 static with aluminum heads.
Iron heads 8.5-8.8.
I know about Dynamic compression calculators
Best test is WOT top end run over 140 . Redline engine under full load pulling real hard.
Don't lift for 30 seconds or longer.
Slow down.
See you still have decent oil pressure & ring seal .
If smoking luke a Sieve out tailpipes....detonation won.
Knocked out Main &!ros bearings obvious detonation took place too.