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

85Bowtie · 06-24-2009, 10:21 AM

I am shortly getting ready to start on my '85 with a ground up resto.

I was wondering if any of you guys could give me a HP figure on what my engine might put out.

It's basically a 400 SB, Keith Black pistons, 9-9.5:1 CR, Lunati Voodoo 256/262, Lift .454/.468 cam, Hedman headers, Performer intake, 600 Edelbrock carb, Summit double hump heads 67cc 2.02/1,60 valves.

Those would be basically my only mods other than machine work, balancing, possibly polishing the intake/head ports. Nothing like a muscle car, just something fun on the street

Thanks

flamingbig10 · 06-24-2009, 10:26 AM

between 300 to 400 horse

jchav62 · 06-24-2009, 11:04 AM

I would say 1 hp per cubic inch. 400...

Alex1 · 06-24-2009, 12:02 PM

350 or so

Cherub · 06-24-2009, 02:37 PM

what do i win if we guess the Hp correctly?

jchav62 · 06-24-2009, 02:53 PM

I'm not a carb guru by any means, but for a 400 with a cam that big and 2.02 heads, wouldn't you want a carburetor with more than 600 cfm's?

silvereagle07 · 06-24-2009, 03:29 PM

I'd say between 350 and 400. It's almost the same setup I had on my old 81 but the comp was 10.5-1 and the cam a little larger. I ran and Holley 750 for awhile but I switched to a street avenger 650. It ran better with the 650cfm. Sounds like a good street setup.

Wild83C10 · 06-24-2009, 09:14 PM

I would say 350 at most. The heads are the limiting factor here.
It will be a decent ride. What trans are you putting behind it?

mongoose · 06-24-2009, 09:31 PM

i'd say 325.. or more.. doubt it will make more than 350..

motor sounds good for a cruiser.. should have good bottom end.. can use a low stall too

Orange77 · 06-24-2009, 10:03 PM

around 400 but why a performer intake go with an RPM at the least if you can afford the rpm airgap go with that one. The carb shouldnt be an issue i believe im running the same 600 or 650 with 202 heads as well as the RPM intake and cam kit. works great heres a graph and info. i had a cracked head and blown gaskets so i got some heads with 202 valves, RPM cam Kit, RPM intake, and i had the carb since my carter went bad and now its a beast. once i do the bottom end it should be even better so yours should be awesome. Im running a TH350 with shift kit and trans cooler as well as 3.73 gears.

mongoose · 06-24-2009, 10:39 PM

420?... dude.. those parts are twice as big as what he has...

that cam is pretty god damn big.. 244@.050".. along with better heads and way bigger headers... etc..

Orange77 · 06-25-2009, 02:32 AM

Your engine is already done? or are the parts you suggested just a parts list? what i suggested earlier was a guide i followed and it worked out as far as the top end goes. i have full length hooker headers. if you havent bought the parts yet then you could use the chart and the parts list as a guide for parts to buy.

85Bowtie · 06-25-2009, 09:48 AM

These are the parts I already laying around the shop with the exception of the heads and pistons.

I may go with a 650 AVS carb now that you mention it. I just want something I can drive and anything is better than the 305 that's in it now.

I'm putting a rebuilt 350 turbo w/shift kit behind it, a 1400 or so stall and 3.42 gears w/posi.

Thanks for all the help

jchav62 · 06-25-2009, 10:52 AM

You may need a higher stall for that cam.

mongoose · 06-25-2009, 01:51 PM

he shouldn't, that cam is tiny.. it won't have any lope at idle.. especially since it's a 400.

Orange77 · 06-25-2009, 02:05 PM

i second that he should be ok with that set up.

pig rig · 06-25-2009, 10:29 PM

my guess is not enough

nico · 06-26-2009, 10:08 AM

Desktop Dyno5 says it will max at 350 hp at 4000 rpm and 528 ft. lbs. at 2500 rpm. I bet this is kinda optimistic, but it will be a torque monster and fall dead on its face after 4000 rpm.

If it was mine, I would go with a bigger cam and more carb.... But I like rough idles.

85Bowtie · 06-26-2009, 11:50 PM

Quote:

Originally Posted by nico

I bet this is kinda optimistic, but it will be a torque monster and fall dead on its face after 4000 rpm.

If it was mine, I would go with a bigger cam and more carb.... But I like rough idles.

The cam I have is supposedly good to 5500 rpm. It's definitely not a stock GM cam, right?

mongoose · 06-27-2009, 12:30 AM

it's comparable to a comp 256.. i had a comp 262 in my 305... and it worked ok, totally streetable.. and you have 95 cubes on me and a smaller cam...

so no.. it's not a stock gm cam.. but imo it's kind of a waste of time.. personally i'd run a 60103, with a little stall like a 2400.. and call it a day.

06-24-2009, 10:21 AM	#1
85Bowtie Registered User Join Date: Mar 2009 Location: TN Posts: 410	Horsepower Guesstimate I am shortly getting ready to start on my '85 with a ground up resto. I was wondering if any of you guys could give me a HP figure on what my engine might put out. It's basically a 400 SB, Keith Black pistons, 9-9.5:1 CR, Lunati Voodoo 256/262, Lift .454/.468 cam, Hedman headers, Performer intake, 600 Edelbrock carb, Summit double hump heads 67cc 2.02/1,60 valves. Those would be basically my only mods other than machine work, balancing, possibly polishing the intake/head ports. Nothing like a muscle car, just something fun on the street Thanks __________________ '69 Dodge Charger R/T 440, 727, 3.55 Sure Grip '68 Plymouth Road Runner 383, 727, 3.23 Sure Grip '89 Dodge Diplomat ex cop car 408, 727, 3.55 Sure Grip '77 Dodge Monaco ex cop car 440, 727, 2.71 '79 Dodge 'Lil Red Express pickup 360, 727, 3.55 Sure Grip '12 Dodge Challenger SRT8 392, M6, 3.92 '85 Chevrolet C-10 SWB 2wd 305, TH350, 2.73

06-24-2009, 10:26 AM	#2
flamingbig10 6.0 powered square Join Date: Feb 2008 Location: Mesquite texas Posts: 3,459	Re: Horsepower Guesstimate between 300 to 400 horse __________________ Aaron 1980 c-10 short bed lowered, cammed 6.0, 4l80e 3600 stall, smp tune, wilwoods, and flames best time so far best et 7.86 @87 on motor 7.57 90 on a 75 shot Build http://67-72chevytrucks.com/vboard/s...d.php?t=283326 Last edited by flamingbig10; 06-24-2009 at 10:27 AM.

06-24-2009, 11:04 AM	#3
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: Horsepower Guesstimate I would say 1 hp per cubic inch. 400... __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4

06-24-2009, 12:02 PM	#4
Alex1 Registered User Join Date: Jul 2007 Location: Ottawa Ontario Canada Posts: 1,156	Re: Horsepower Guesstimate 350 or so

06-24-2009, 02:37 PM	#5
Cherub Registered User Join Date: Feb 2008 Location: Houston Posts: 970	Re: Horsepower Guesstimate what do i win if we guess the Hp correctly? __________________ 2014 LTZ Z71 Silverado 82 C15 LQ4/4L80E Conversion 78 Suburban build (SOLD) 83 4x4 Suburban(SOLD) 82 C15 (my first truck)

06-24-2009, 02:53 PM	#6
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: Horsepower Guesstimate I'm not a carb guru by any means, but for a 400 with a cam that big and 2.02 heads, wouldn't you want a carburetor with more than 600 cfm's? __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4 Last edited by jchav62; 06-24-2009 at 02:53 PM.

06-24-2009, 03:29 PM	#7
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: Horsepower Guesstimate I'd say between 350 and 400. It's almost the same setup I had on my old 81 but the comp was 10.5-1 and the cam a little larger. I ran and Holley 750 for awhile but I switched to a street avenger 650. It ran better with the 650cfm. Sounds like a good street setup. __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT

06-24-2009, 09:14 PM	#8
Wild83C10 Registered User Join Date: May 2002 Location: NJ Posts: 910	Re: Horsepower Guesstimate I would say 350 at most. The heads are the limiting factor here. It will be a decent ride. What trans are you putting behind it? __________________ 83 C10 Stepside (SOLD, it was a blast!) 383 MASS-FLO EFI/TKO II 600/3.90 Posi 10 bolt S475 and C4 DM running, fine tuning turbo= Douchebag Racing: Runs Fine all the Time

06-24-2009, 09:31 PM	#9
mongoose Registered User Join Date: Feb 2009 Location: slurrey, bc. Posts: 1,134	Re: Horsepower Guesstimate i'd say 325.. or more.. doubt it will make more than 350.. motor sounds good for a cruiser.. should have good bottom end.. can use a low stall too __________________ -'73 c/10 - Low with Go - will be complete... probably never. -'90 2wd Blazer - well... soon enough anyways. -'84 SWB - the daily gas guzzler.

06-24-2009, 10:03 PM	#10
Orange77 Registered User Join Date: Apr 2009 Location: Tucson, AZ Posts: 184	Re: Horsepower Guesstimate around 400 but why a performer intake go with an RPM at the least if you can afford the rpm airgap go with that one. The carb shouldnt be an issue i believe im running the same 600 or 650 with 202 heads as well as the RPM intake and cam kit. works great heres a graph and info. i had a cracked head and blown gaskets so i got some heads with 202 valves, RPM cam Kit, RPM intake, and i had the carb since my carter went bad and now its a beast. once i do the bottom end it should be even better so yours should be awesome. Im running a TH350 with shift kit and trans cooler as well as 3.73 gears. Attached Images

06-24-2009, 10:39 PM	#11
mongoose Registered User Join Date: Feb 2009 Location: slurrey, bc. Posts: 1,134	Re: Horsepower Guesstimate 420?... dude.. those parts are twice as big as what he has... that cam is pretty god damn big.. 244@.050".. along with better heads and way bigger headers... etc.. __________________ -'73 c/10 - Low with Go - will be complete... probably never. -'90 2wd Blazer - well... soon enough anyways. -'84 SWB - the daily gas guzzler.

06-25-2009, 02:32 AM	#12
Orange77 Registered User Join Date: Apr 2009 Location: Tucson, AZ Posts: 184	Re: Horsepower Guesstimate Your engine is already done? or are the parts you suggested just a parts list? what i suggested earlier was a guide i followed and it worked out as far as the top end goes. i have full length hooker headers. if you havent bought the parts yet then you could use the chart and the parts list as a guide for parts to buy.

06-25-2009, 09:48 AM	#13
85Bowtie Registered User Join Date: Mar 2009 Location: TN Posts: 410	Re: Horsepower Guesstimate These are the parts I already laying around the shop with the exception of the heads and pistons. I may go with a 650 AVS carb now that you mention it. I just want something I can drive and anything is better than the 305 that's in it now. I'm putting a rebuilt 350 turbo w/shift kit behind it, a 1400 or so stall and 3.42 gears w/posi. Thanks for all the help __________________ '69 Dodge Charger R/T 440, 727, 3.55 Sure Grip '68 Plymouth Road Runner 383, 727, 3.23 Sure Grip '89 Dodge Diplomat ex cop car 408, 727, 3.55 Sure Grip '77 Dodge Monaco ex cop car 440, 727, 2.71 '79 Dodge 'Lil Red Express pickup 360, 727, 3.55 Sure Grip '12 Dodge Challenger SRT8 392, M6, 3.92 '85 Chevrolet C-10 SWB 2wd 305, TH350, 2.73

06-25-2009, 10:52 AM	#14
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: Horsepower Guesstimate You may need a higher stall for that cam. __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4

06-25-2009, 01:51 PM	#15
mongoose Registered User Join Date: Feb 2009 Location: slurrey, bc. Posts: 1,134	Re: Horsepower Guesstimate he shouldn't, that cam is tiny.. it won't have any lope at idle.. especially since it's a 400. __________________ -'73 c/10 - Low with Go - will be complete... probably never. -'90 2wd Blazer - well... soon enough anyways. -'84 SWB - the daily gas guzzler.



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06-25-2009, 02:05 PM	#16
Orange77 Registered User Join Date: Apr 2009 Location: Tucson, AZ Posts: 184	Re: Horsepower Guesstimate i second that he should be ok with that set up.

06-25-2009, 10:29 PM	#17
pig rig Registered User Join Date: Feb 2009 Location: washington the state Posts: 730	Re: Horsepower Guesstimate my guess is not enough __________________ my sports car rolls on six wheels only because I'm to fat to get in and out of new corvette http://hubgarage.s3.amazonaws.com/ph...ped_detail.JPG

06-26-2009, 10:08 AM	#18
nico Registered User Join Date: Nov 2006 Location: Marietta, OK Posts: 153	Re: Horsepower Guesstimate Desktop Dyno5 says it will max at 350 hp at 4000 rpm and 528 ft. lbs. at 2500 rpm. I bet this is kinda optimistic, but it will be a torque monster and fall dead on its face after 4000 rpm. If it was mine, I would go with a bigger cam and more carb.... But I like rough idles.

06-27-2009, 12:30 AM	#20
mongoose Registered User Join Date: Feb 2009 Location: slurrey, bc. Posts: 1,134	Re: Horsepower Guesstimate it's comparable to a comp 256.. i had a comp 262 in my 305... and it worked ok, totally streetable.. and you have 95 cubes on me and a smaller cam... so no.. it's not a stock gm cam.. but imo it's kind of a waste of time.. personally i'd run a 60103, with a little stall like a 2400.. and call it a day. __________________ -'73 c/10 - Low with Go - will be complete... probably never. -'90 2wd Blazer - well... soon enough anyways. -'84 SWB - the daily gas guzzler.

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