Engine Horsepower Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tim21391 · 11-19-2007, 11:52 PM

im just wondering....my engine was rebuilt about 10,000 miles ago by a guy who builds race engines......its a 402 big block..edelbrock performance intake..k&n air filter..performance heads....idk what kind they are...bored .30 over...holly 4 barrel double pumper..i think its a 750?...distributor is has points....mechanical fuel pump..premium gas...400 turbo tranny with a shift kit.....im 16 years old and i was wondering how much horsepower im pushin out at the wheels

dave2953 · 11-20-2007, 12:23 AM

Not sure, but I'll bet it's quite a bit. You're pretty lucky to have a motor like that. There's lots of guys that would love to have a powerplant as nice as yours. Have you thought about taking it for a dyno run?

Slammed70 · 11-20-2007, 12:40 AM

Who in Kansas did you buy that from? Is it a black GMC?

If Im thinking right, that might be the old engine I had in my S-15.

Edit: Nevermind...I looked at your profile thing and see that its a green Chevy. Your not the person Im thinking of.

*Billla* · 11-20-2007, 01:20 AM

Share the cam specs and I'll give a pretty good guess

LMN8UR · 11-20-2007, 01:48 AM

You could ask around to barrow a G-Tech Pro.

Nice engine. Please take care of it.

Slammed70 · 11-20-2007, 02:24 AM

Quote:

Originally Posted by Billla

Share the cam specs and I'll give a pretty good guess

Oooo-ooo, do mine...

1973 SBC 350-.030 over

Stock crank
Speedpro "Powerforged" flat top pistons
Total-seal TSS rings
Lunati Voodoo .468/.489 lift 262/268 duration
Pete Jackson "Noisy" gear drive
Roades V-max hydraulic lifters
0.039 head gaskets
Dart "Iron eagle" heads 180cc/64cc and 2.02/1.60
Pro comp 1.5 shaft-mount roller rockers
Edelbrock Performer RPM intake
1.5 inch spacer
Holley "Street Avenger" 770CFM
Cheap chrome aircleaner with cheap paper 6" element
MSD Pro-Billet with Autozone coil (Gimp, I know but shut up)
MSD "Street fire" 8mm wires
Neal Chance 1800ish stall converter
TH350 with B&M "Steet" Transpak
Hedman "Block hugger" headers
2.5 duals with Flowmaster 1 chamber "race only" mufflers

Were guessing around 10:1 compresion and around 420+HP/400+TQ with an RPM range of 2000-6000.

What do you think?

70GMCer · 11-20-2007, 07:24 AM

Quote:

Originally Posted by Slammed70

Oooo-ooo, do mine...

1973 SBC 350-.030 over

Stock crank
Speedpro "Powerforged" flat top pistons
Total-seal TSS rings
Lunati Voodoo .468/.489 lift 262/268 duration
Pete Jackson "Noisy" gear drive
Roades V-max hydraulic lifters
0.039 head gaskets
Dart "Iron eagle" heads 180cc/64cc and 2.02/1.60
Pro comp 1.5 shaft-mount roller rockers
Edelbrock Performer RPM intake
1.5 inch spacer
Holley "Street Avenger" 770CFM
Cheap chrome aircleaner with cheap paper 6" element
MSD Pro-Billet with Autozone coil (Gimp, I know but shut up)
MSD "Street fire" 8mm wires
Neal Chance 1800ish stall converter
TH350 with B&M "Steet" Transpak
Hedman "Block hugger" headers
2.5 duals with Flowmaster 1 chamber "race only" mufflers

Were guessing around 10:1 compresion and around 420+HP/400+TQ with an RPM range of 2000-6000.

What do you think?

This is what I came up with on yours.....Slammed70 Need more info from tim21391

Slammed70 · 11-20-2007, 06:24 PM

Wow, we were close....or as close as Desktop Dyno will guess apparently.

69swbman · 11-20-2007, 11:26 PM

70gmcer what information do u need for input in that chart

70GMCer · 11-21-2007, 07:12 AM

Quote:

Originally Posted by 69swbman

70gmcer what information do u need for input in that chart

Compression, cam specs, carb specs, cylinder head type and size of valves, type of intake manifold and if you are using headers.

bowtieboy93 · 11-21-2007, 09:09 AM

what program are you using for the dyno?

*Billla* · 11-21-2007, 09:26 AM

There's a thread for DD requests:

http://67-72chevytrucks.com/vboard/s...op+dyno+thread

streetstar · 11-21-2007, 12:59 PM

Quote:

Originally Posted by tim21391

im just wondering....my engine was rebuilt about 10,000 miles ago by a guy who builds race engines......its a 402 big block..edelbrock performance intake..k&n air filter..performance heads....idk what kind they are...bored .30 over...holly 4 barrel double pumper..i think its a 750?...distributor is has points....mechanical fuel pump..premium gas...400 turbo tranny with a shift kit.....im 16 years old and i was wondering how much horsepower im pushin out at the wheels

i would guess 250 - 275 -- has more torque than that though, i would guess

But i am making my guess under the assumption that the heads are basically stock and it has an RV type cam

Ackattack · 11-21-2007, 02:29 PM

yeah, the cam selection is going to be the variable that determines the power the most. I mean, if you take the exact same engine and put in a stock type low duration, low lift cam you'd be looking at low to mid 200 HP. Put in a high lift long duration cam and you could easily see over 400.

The heads, intake, and exhaust also all factor into this, but the cam is the main factor.

cruiserman · 11-21-2007, 02:48 PM

Is that an AC compressor on the left side in that picture? What mounting bracket are you using for that?

70GMCer · 11-21-2007, 03:33 PM

Quote:

Originally Posted by Billla

There's a thread for DD requests:

http://67-72chevytrucks.com/vboard/s...op+dyno+thread

Thanks Billla.....I couldn't find that thread to give out......

Jtrux · 11-21-2007, 06:50 PM

Quote:

Originally Posted by cruiserman

Is that an AC compressor on the left side in that picture? What mounting bracket are you using for that?

I was wondering the same thing.

tim21391 · 01-04-2008, 01:43 PM

yeah its the ac thing...i dont know how its like that....some dude whho builds race engines built my engine....the heads are performance heads all i know and its bored over .030 or something like that.....all i know is that....it can do a second gear tire squeel and its an automatic

68Stepbed · 01-05-2008, 04:08 AM

I would definetly change that points distributor to an HEI for more reliable spark.

tim21391 · 01-13-2008, 06:40 AM

im going to eventually when its warmer outside..to cold for me to work on it right now in this season

piecesparts · 01-13-2008, 07:16 AM

So Tim; Where in Kansas are you residing?

Can you get more info on the engine build? You have some of the basics, but there are some serious power builder tems we need to know.

panhandler62 · 01-13-2008, 07:20 AM

I'm gonna throw some 'sketi at the wall and guess somewhere between about 260 and 300hp at the rear wheels.

**70cst** · 01-13-2008, 07:53 AM

Wasn't the factory 402BB rated at 310hp. At least in 70 that's what my specs read.

panhandler62 · 01-13-2008, 08:36 AM

That would be gross HP at the flywheel though, not SAE net.

mnunn454 · 01-14-2008, 05:36 AM

Assuming it's 400 HP at the flywheel (a little high for a 402 unless it's got a pretty steep cam to go with the parts listed), my guess is about 300 RWHP. You'll loose 25% or more getting to the road because of the drivetrain friction/heat loss. Alternator, power steering and water pump probably weren't figured in into that 400 rating either, so there goes another 25-40 rear wheel horses. A rear wheel dyno pull or two for about $75 should tell all.

BTW, I envy you having a truck like this at 16 years old. All I could afford at your age was mom and dad's "hand-me-down" 61 Buick Invicta. It took me 35 years to get what you have now, a BBC Classic Chevy truck.

Take care of it. Resist the temptation to drive carelessly. That's quite a jewel. If the temptation gets too great, let me know and I'll come buy it from you!

11-19-2007, 11:52 PM	#1
tim21391 Registered User Join Date: Jul 2007 Location: Salina, Kansas Posts: 1,998	Engine Horsepower Question im just wondering....my engine was rebuilt about 10,000 miles ago by a guy who builds race engines......its a 402 big block..edelbrock performance intake..k&n air filter..performance heads....idk what kind they are...bored .30 over...holly 4 barrel double pumper..i think its a 750?...distributor is has points....mechanical fuel pump..premium gas...400 turbo tranny with a shift kit.....im 16 years old and i was wondering how much horsepower im pushin out at the wheels Attached Images

11-20-2007, 12:23 AM	#2
dave2953 Dave's not here, man Join Date: Jun 2004 Location: Winder, Georgia Posts: 2,000	Re: Engine Horsepower Question Not sure, but I'll bet it's quite a bit. You're pretty lucky to have a motor like that. There's lots of guys that would love to have a powerplant as nice as yours. Have you thought about taking it for a dyno run? __________________ - 2014 VW Jetta - 2015 VW Jetta - 1966 Ford F-250 Last edited by dave2953; 11-20-2007 at 12:24 AM.

11-20-2007, 01:20 AM	#4
Billla Account Suspended Join Date: Sep 2005 Location: Monroe, WA Posts: 3,814	Re: Engine Horsepower Question Share the cam specs and I'll give a pretty good guess

11-20-2007, 01:48 AM	#5
LMN8UR Registered User Join Date: Jun 2005 Location: Midlothian, VA Posts: 148	Re: Engine Horsepower Question You could ask around to barrow a G-Tech Pro. Nice engine. Please take care of it. __________________ 72 Chevy C-10 Custom LWB 383 Stroker - Edlebrock Air Gap intake and 670 CFM Holley Street Avenger carb. Hooker Comp Headers w/ X-Pipe and 2.25 duals TKO-500 & 3.08:1 rear I Love HEMI's, they're soft & chewy!

11-20-2007, 11:26 PM	#9
69swbman Registered User Join Date: Jun 2007 Location: peaster,tx Posts: 59	Re: Engine Horsepower Question 70gmcer what information do u need for input in that chart

11-21-2007, 09:09 AM	#11
bowtieboy93 Registered User Join Date: Feb 2007 Location: (Cloverdale) Surrey BC Canada Posts: 1,566	Re: Engine Horsepower Question what program are you using for the dyno? __________________ Travis travis_moffatt@hotmail.com 1969 Chevrolet C-10 LWB, 350c.i., TH350, In Pieces. 1991 GMC Sonoma, IROCS s10 grill 1963 Ford Galaxie 351/C4

11-21-2007, 09:26 AM	#12
Billla Account Suspended Join Date: Sep 2005 Location: Monroe, WA Posts: 3,814	Re: Engine Horsepower Question There's a thread for DD requests: http://67-72chevytrucks.com/vboard/s...op+dyno+thread

11-21-2007, 02:29 PM	#14
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,524	Re: Engine Horsepower Question yeah, the cam selection is going to be the variable that determines the power the most. I mean, if you take the exact same engine and put in a stock type low duration, low lift cam you'd be looking at low to mid 200 HP. Put in a high lift long duration cam and you could easily see over 400. The heads, intake, and exhaust also all factor into this, but the cam is the main factor. __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

11-21-2007, 02:48 PM	#15
cruiserman Registered User Join Date: Dec 2006 Location: Idaho Posts: 210	Re: Engine Horsepower Question Is that an AC compressor on the left side in that picture? What mounting bracket are you using for that? __________________ 72 C2500 LWB 402 Sierra Grande 05 Odyssey 08 Tundra

01-04-2008, 01:43 PM	#18
tim21391 Registered User Join Date: Jul 2007 Location: Salina, Kansas Posts: 1,998	Re: Engine Horsepower Question yeah its the ac thing...i dont know how its like that....some dude whho builds race engines built my engine....the heads are performance heads all i know and its bored over .030 or something like that.....all i know is that....it can do a second gear tire squeel and its an automatic

01-05-2008, 04:08 AM	#19
68Stepbed Registered User Join Date: Mar 2005 Location: 10-Uh-See Posts: 5,609	Re: Engine Horsepower Question I would definetly change that points distributor to an HEI for more reliable spark. __________________ Matt 68 C10 stepside, LS1/700R4, TCI Engineering suspension system

01-13-2008, 06:40 AM	#20
tim21391 Registered User Join Date: Jul 2007 Location: Salina, Kansas Posts: 1,998	Re: Engine Horsepower Question im going to eventually when its warmer outside..to cold for me to work on it right now in this season

01-13-2008, 07:16 AM	#21
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Engine Horsepower Question So Tim; Where in Kansas are you residing? Can you get more info on the engine build? You have some of the basics, but there are some serious power builder tems we need to know.

01-13-2008, 07:20 AM	#22
panhandler62 Java Mechanic Join Date: Jun 2005 Location: Martinsburg, WV Posts: 6,763	Re: Engine Horsepower Question I'm gonna throw some 'sketi at the wall and guess somewhere between about 260 and 300hp at the rear wheels. __________________ Keith 11 Lincoln MKT -- Momma's wagon 13 G37xS -- middle age crazy car 68 C20 Fleetside -- RIP Decorating the whole town up at a cost of $27 ....

01-13-2008, 07:53 AM	#23
70cst Senior Member Join Date: Feb 2001 Location: New Madison, Ohio Posts: 21,373	Re: Engine Horsepower Question Wasn't the factory 402BB rated at 310hp. At least in 70 that's what my specs read. __________________ A husband can be right...or...A husband can be happy. 67-72 Chevy and GMC Trucks...The Classic Truck for the Classic Folk. 1970 CST Two tone green, 402BB, 400 Automatic, Tach, Buckets, AC, AM-FM, Tilt, GM CB, GM 8 Tract, LWB, etc JOHN 17:3...The better side of "LIFE" Remember: Everyday is a good day...Some are just gooder!



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01-13-2008, 08:36 AM	#24
panhandler62 Java Mechanic Join Date: Jun 2005 Location: Martinsburg, WV Posts: 6,763	Re: Engine Horsepower Question That would be gross HP at the flywheel though, not SAE net. __________________ Keith 11 Lincoln MKT -- Momma's wagon 13 G37xS -- middle age crazy car 68 C20 Fleetside -- RIP Decorating the whole town up at a cost of $27 ....

01-14-2008, 05:36 AM	#25
mnunn454 Registered User Join Date: Dec 2006 Location: Rhode Island Posts: 602	Re: Engine Horsepower Question Assuming it's 400 HP at the flywheel (a little high for a 402 unless it's got a pretty steep cam to go with the parts listed), my guess is about 300 RWHP. You'll loose 25% or more getting to the road because of the drivetrain friction/heat loss. Alternator, power steering and water pump probably weren't figured in into that 400 rating either, so there goes another 25-40 rear wheel horses. A rear wheel dyno pull or two for about $75 should tell all. BTW, I envy you having a truck like this at 16 years old. All I could afford at your age was mom and dad's "hand-me-down" 61 Buick Invicta. It took me 35 years to get what you have now, a BBC Classic Chevy truck. Take care of it. Resist the temptation to drive carelessly. That's quite a jewel. If the temptation gets too great, let me know and I'll come buy it from you! __________________ 69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe

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