How many crank HP will my old rebuilt 406 make?
05-22-2007, 08:07 AM
#1
Team Owner
Thread Starter
How many crank HP will my old rebuilt 406 make?
In about 10 days, I'll put the rebuilt 406 out of my Race Vette on the engine dyno.
I have never had the engine dynoed after the last rebuild, but I'm guessing that the output was somewhere in the 600 - 630 HP range as I ran 10.35 @ 127.59 mph on engine in the 1/4 mile
The OLD build (before the current rebuild) had following specs:
400 block, bored .030 over
3.75 stroke Eagle forged 4340 crank crank = 406 cubic inches
Eagle forged 6 inch H-beam rods
Probe flat top pistons
solid roller cam with 261/270 degrees .050 duration and about .670 lift
Dart Pro 1 heads with 230 cc intake runners (flowing about 290 cfm intake/210 cfm exhaust) and 64 cc chambers
12.8 : 1 compression
1.6 ratio roller rockers & stud girdles
The NEW build is identical except for heads and compression..
New heads are PRO TOPLINE 235 cc intake runner heads with 56 cc chambers (flat milled to 56cc as they originally were 64 cc heads)
Those heads flow out of the box approx. 312/190 cfm and they were fully race ported, so they probably flow somewhere in the 330/230 cfm range. The raised compression due to the 56 cc chambers should put the compression somewhere in the 13.2 - 13.5 : 1 range.
The main bearing clearance on the new build is 3 thousands.
The intake is a 2825 CNC ported Edelbrock Super Victor Intake and the carb is a 1000 cfm Holley HP series carb (80514)
So, how many HP will the new build make?
I have never had the engine dynoed after the last rebuild, but I'm guessing that the output was somewhere in the 600 - 630 HP range as I ran 10.35 @ 127.59 mph on engine in the 1/4 mile
The OLD build (before the current rebuild) had following specs:
400 block, bored .030 over
3.75 stroke Eagle forged 4340 crank crank = 406 cubic inches
Eagle forged 6 inch H-beam rods
Probe flat top pistons
solid roller cam with 261/270 degrees .050 duration and about .670 lift
Dart Pro 1 heads with 230 cc intake runners (flowing about 290 cfm intake/210 cfm exhaust) and 64 cc chambers
12.8 : 1 compression
1.6 ratio roller rockers & stud girdles
The NEW build is identical except for heads and compression..
New heads are PRO TOPLINE 235 cc intake runner heads with 56 cc chambers (flat milled to 56cc as they originally were 64 cc heads)
Those heads flow out of the box approx. 312/190 cfm and they were fully race ported, so they probably flow somewhere in the 330/230 cfm range. The raised compression due to the 56 cc chambers should put the compression somewhere in the 13.2 - 13.5 : 1 range.
The main bearing clearance on the new build is 3 thousands.
The intake is a 2825 CNC ported Edelbrock Super Victor Intake and the carb is a 1000 cfm Holley HP series carb (80514)
So, how many HP will the new build make?
Last edited by GrandSportC3; 05-22-2007 at 08:57 AM.
05-22-2007, 09:34 AM
#5
Team Owner
Thread Starter
nobody has voted yet that it will blow up on the dyno 
It's my first build and the reason that I put the engine on the dyno is to make sure that I didn't mess anything up on the build...
It's my first build and the reason that I put the engine on the dyno is to make sure that I didn't mess anything up on the build...
05-22-2007, 09:43 AM
#6
Team Owner
Thread Starter
The limiting factor on 23 degrees headed engines is uslally the heads.. I have not had those new heads flowed but as they are high flowing heads out of the box and considering the race porting (which seems very well done), it should flow enough to support up to 700 HP but I doubt that I'm close to 700 HP..
05-22-2007, 10:09 AM
#10
Safety Car
Oliver, have you ran any calculations to see how much the compression will be raised by going from 64 to 56 cc chambers? or is it more of a SWAG ?? Just off top my head it seems like it might be more than 13.5 to 1........don't know for sure though.
Assuming the motor is 13.5 I would guess 650-675 hp.
Assuming the motor is 13.5 I would guess 650-675 hp.
05-22-2007, 10:12 AM
#11
Team Owner
Thread Starter
Oliver, have you ran any calculations to see how much the compression will be raised by going from 64 to 56 cc chambers? or is it more of a SWAG ?? Just off top my head it seems like it might be more than 13.5 to 1........don't know for sure though.
Assuming the motor is 13.5 I would guess 650-675 hp.
Assuming the motor is 13.5 I would guess 650-675 hp.
http://www.smokemup.com
However, I don't have the exact specs for deck height etc.. I also don't know what thickness head gasket was used on the old build etc. etc..
You Entered:
Bore 4.155 (inches)
Stroke 3.75 (inches)
Rod Length 6 (inches)
Cyl. Head Vol. 56 (cc)
Deck Height 0.000 (inches) (NOT SURE but I think that the block was zero-decked)
Head Gasket Bore 4.155 (inches) (NOT SURE)
Head Gasket Thickness 0.039 (inches) (that's what I'm planning on using)
Piston to Cyl. Wall Clearance 0.003 (inches) (NOT SURE - default value)
Top Ring Land Height 0.25 (inches) (NOT SURE - default value)
Piston Dome Vol. -2 (cc) (NOT SURE, they are flat top pistons with 2 valve reliefs.. Don't know how many cc the valve reliefs have)
Compression Ratio:
13.488 : 1
Bore / Stroke Ratio:
1.108 : 1
Rod / Stroke Ratio:
1.6 : 1
Total volume:
900.113 cc's
Compressed volume:
66.735 cc's
I can only estimate the compression as I don't have the equipment to measure all those measurements..
Last edited by GrandSportC3; 05-22-2007 at 10:17 AM.
05-22-2007, 12:16 PM
#13
Team Owner
Thread Starter
It depends on where the engine will peak.. Initially, we will go to 6800 and I'm pretty sure that it'll peak earlier.. I used to shift at 6800 RPM with that engine (with different heads)
05-30-2007, 07:08 AM
#17
Pro
Member Since: Dec 2006
Location: wilmington nc
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What in the world? Did i guess to low and shut the thread down? No one hasen"t posted in a week! 100 people voted on a hood poll and only 25 voted on a horsepower poll. Where"s all the go fast people at, if you don"t know how to guess at h.p. just do like i did, take the hp of your vette and double it
05-30-2007, 07:26 AM
#18
Team Owner
Thread Starter
UPADTE: Getting closer.. Just need the correct length pushrods and I'll be ready to finish the assembly of the engine.. Hope that I'll be able to run it on the dyno early next week..hopefully Monday or Tuesday..
06-07-2007, 10:36 AM
#19
Team Owner
Thread Starter
Dropped the 406 off at the shop today... They won't get to my engine until some time next week... I'll keep you all updated!
