SBC 383 500ft/lb torque build

General engine tech -- Drag Racing to Circle Track

Moderator: Team

mtmvette
New Member
New Member
Posts: 4
Joined: Sun Aug 18, 2013 12:49 pm

SBC 383 500ft/lb torque build

Post by mtmvette » Sat Apr 14, 2018 10:39 pm

383 non roller, forged pistons, scat cast crank, 9.5c, Gm Vortec heads.

Will be used in 1979 Chevy HD 1500. Tow vehicle and work truck. Need to know if I can reach 475 to 500ft/lbs in the low rpm range, and if so what cam would do it?????? If the vortecs are not up to par, maybe guide me with head choice as well.

Thanks in advance - MTM

rustbucket79
Guru
Guru
Posts: 1536
Joined: Fri Apr 07, 2006 8:23 pm

Re: SBC 383 500ft/lb torque build

Post by rustbucket79 » Mon Apr 16, 2018 12:01 am

Subscribing.

Gobs of low RPM torque from an old school build is usually a function of large displacement or a big diesel. I would love to see an example of a pump gas, towing 383 that approaches 500 lb. ft. at say 2500 to 3000 RPM.

PackardV8
Guru
Guru
Posts: 5241
Joined: Sun Jul 30, 2006 2:03 pm

Re: SBC 383 500ft/lb torque build

Post by PackardV8 » Mon Apr 16, 2018 1:24 am

Turbo
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering

SupStk
Guru
Guru
Posts: 1238
Joined: Wed Jun 22, 2005 6:25 pm
Location: Box Elder, SD

Re: SBC 383 500ft/lb torque build

Post by SupStk » Mon Apr 16, 2018 3:14 am

1.3 lb ft per ci is a somewhat serious build. Doing it on a budget and at RPM suitable for towing is something I'd like to hear about.
Monty Frerichs
B&M Machine

Cubic_Cleveland
Guru
Guru
Posts: 1117
Joined: Thu Feb 23, 2012 11:44 pm
Location: Australia

Re: SBC 383 500ft/lb torque build

Post by Cubic_Cleveland » Mon Apr 16, 2018 3:24 am

PackardV8 wrote:
Mon Apr 16, 2018 1:24 am
Turbo
Best way to do it!

mtmvette
New Member
New Member
Posts: 4
Joined: Sun Aug 18, 2013 12:49 pm

Re: SBC 383 500ft/lb torque build

Post by mtmvette » Mon Apr 16, 2018 7:18 am

I never had look with a turbo at the low end, but that was nearly 40 years ago. The engine will be for my tow work truck simplest the better. Approaching 500ftlbs sounds better. Interesting, under the "advancing a cam" thread, I read a post by raceman14 who say he built an engine very close to what I am looking for. I don't know if he is still on this forum ... I sure would like to here more about that build as he was somewhat vague on details. Anybody else with similar builds, your knowledge would be much appreciated.

steve316
Pro
Pro
Posts: 424
Joined: Fri Apr 13, 2007 10:06 pm
Location: St.Joseph,mo.

Re: SBC 383 500ft/lb torque build

Post by steve316 » Mon Apr 16, 2018 8:32 am

Your peak torque wood be in the 4000 rpm range. Your budget will determine how much torque. Post how much you are willing to spend on this project.

ptuomov
Guru
Guru
Posts: 1796
Joined: Fri Aug 07, 2009 3:52 am

Re: SBC 383 500ft/lb torque build

Post by ptuomov » Mon Apr 16, 2018 8:38 am

mtmvette wrote:
Mon Apr 16, 2018 7:18 am
I never had look with a turbo at the low end, but that was nearly 40 years ago. The engine will be for my tow work truck simplest the better. Approaching 500ftlbs sounds better. Interesting, under the "advancing a cam" thread, I read a post by raceman14 who say he built an engine very close to what I am looking for. I don't know if he is still on this forum ... I sure would like to here more about that build as he was somewhat vague on details. Anybody else with similar builds, your knowledge would be much appreciated.
In my opinion, by far the cheapest and most reliable way to produce that kind of low rpm torque with good drivability and nice idle is a well-engineered turbo kit. What I’d go for is stock truck cam and relatively small turbine hot side(s).
[b]Paradigms often shift without the clutch[/b] -- [url]https://www.youtube.com/watch?v=cxn-LxwsrnU[/url]

User avatar
CamKing
Guru
Guru
Posts: 8447
Joined: Wed Aug 08, 2007 4:05 pm
Location: Denver, NC
Contact:

Re: SBC 383 500ft/lb torque build

Post by CamKing » Mon Apr 16, 2018 10:25 am

If you are planning on running 92 octane gas, I'd say 475ft/lbs is about the best you can hope for, normally asperated.
If you can run e85, you can get to the 500ft/lbs, with 12:1 compression.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
(704)489-2449

groberts101
Guru
Guru
Posts: 1535
Joined: Sat Mar 08, 2008 3:08 pm
Location: Minneapolis

Re: SBC 383 500ft/lb torque build

Post by groberts101 » Mon Apr 16, 2018 11:27 am

I agree with Mike. And 450 would be much more realistic with those heads but induction will likely be your biggest limiting factor on where you end up. From there the gains per dollar spent goes up pretty fast. Bigger compression with E85 is well worth it(good power increase/$$$ investment).. IF you have the availability to make that combo work for you. Long tube headers and good exhaust will be needed as well.

PackardV8
Guru
Guru
Posts: 5241
Joined: Sun Jul 30, 2006 2:03 pm

Re: SBC 383 500ft/lb torque build

Post by PackardV8 » Mon Apr 16, 2018 11:42 am

Need to know if I can reach 475 to 500ft/lbs in the low rpm range,
CamKing wrote:
Mon Apr 16, 2018 10:25 am
If you are planning on running 92 octane gas, I'd say 475ft/lbs is about the best you can hope for, normally asperated. If you can run e85, you can get to the 500ft/lbs, with 12:1 compression.
Mike, you're always spot on with your calculations, but neglected to furnish the RPM.

Would we define low RPM towing range as sub-3500? If so, who'd be comfortable with putting a 12:1 383" in a sustained WOT pull?

FWIW, modern computer controlled direct injection turbocharged truck engines make more than 1.3 lb ft per ci and come with a warranty. The Ford F-150 twin-turbo 2.7 L V6 EcoBoost engine delivers 325 hp and 375 lb⋅ft (2.27 lbs/ft cu in). Could our OP build and tune a 383" to 870 lbs/ft from scratch?. Experience says probably not, but with a small turbo and a safe tune, 500 lbs ft @ 3500 is cake.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering

Newold1
Guru
Guru
Posts: 1184
Joined: Fri Apr 08, 2016 9:50 am

Re: SBC 383 500ft/lb torque build

Post by Newold1 » Mon Apr 16, 2018 12:23 pm

This would be my build suggestion and it will get you to 500ft. lbs and 385 HP out of a 396 inch engine. 4.100" bore with a 3.75" stroke with a 6" budget rod and static compression of 10.5 to 1. A hydraulic roller camshaft with 215 duration @50 on intake, 220 duration @50 on exhaust with a 110 lobe center and an 114 LSA with lifts on intake and exhausts both at .520". Vortec heads with 2.02 intake with slight bowl cleanup and proper 5 angle valve throat. 1.65" exhaust with good seat and radius throat finish under seat. A good aftermarket cast crankshaft. a nice set of 4032 forged pistons with 1.5, 1.5mm and 3.0mm standard tension top moly rings and a piston clearance of about .0045" and nice 12-20 RA bore plateau finish. Put a nice dual plane air gap intake manifold and a well built either quadrijet or 650 Holley carb and a good billet HEi with a MSD spark control and exhaust with a nice set of street tri-y 1-5/8" headers into a 3" collector and a nice 2" exhaust pipes thru a nice set of Spintron SS mufflers and you've got the the best truck small block high torque levels between 2500-3500 rpms on pump gas you could want. None of the above is exotic or high dollar, just good simple well matched components to get you the torque and HP you've requested with your post. This engine properly tuned will provide nice cruising manners and mileage with a smooth easy foot and when you want to stretch it's legs it will run! :wink:
Last edited by Newold1 on Mon Apr 16, 2018 1:06 pm, edited 1 time in total.

Amilcar
Pro
Pro
Posts: 268
Joined: Mon Jun 20, 2011 9:32 am
Location: Brazil

Re: SBC 383 500ft/lb torque build

Post by Amilcar » Mon Apr 16, 2018 12:37 pm

Newold1 wrote:
Mon Apr 16, 2018 12:23 pm
This would be my build suggestion and it will get you to 500ft. lbs and 385 HP out of a 396 inch engine. 4.100" bore with a 3.75" stroke with a 6" budget rod and static compression of 10.5 to 1. A hydraulic roller camshaft with 215 duration @50 on intake, 220 duration @50 on exhaust with a 110 lobe center and an 114 LSA with lifts on intake and exhausts both at .520". Vortec heads with 2.20 intake with slight bowl cleanup and proper 5 angle valve throat. 1.65" exhaust with good seat and radius throat finish under seat. A good aftermarket cast crankshaft. a nice set of 4032 forged pistons with 1.5, 1.5mm and 3.0mm standard tension top moly rings and a piston clearance of about .0045" and nice 12-20 RA bore plateau finish. Put a nice dual plane air gap intake manifold and a well built either quadrijet or 650 Holley carb and a good billet HEi with a MSD spark control and exhaust with a nice set of street tri-y 1-5/8" headers into a 3" collector and a nice 2" exhaust pipes thru a nice set of Spintron SS mufflers and you've got the the best truck small block high torque levels between 2500-3500 rpms on pump gas you could want. None of the above is exotic or high dollar, just good simple well matched components to get you the torque and HP you've requested with your post. This engine properly tuned will provide nice cruising manners and mileage with a smooth easy foot and when you want to stretch it's legs it will run! :wink:
Did you mean 2.02" I think?

Newold1
Guru
Guru
Posts: 1184
Joined: Fri Apr 08, 2016 9:50 am

Re: SBC 383 500ft/lb torque build

Post by Newold1 » Mon Apr 16, 2018 1:07 pm

Thanks, already corrected that typo.

gnicholson
Pro
Pro
Posts: 344
Joined: Tue May 06, 2008 9:59 pm
Location: kansas city mo

Re: SBC 383 500ft/lb torque build

Post by gnicholson » Mon Apr 16, 2018 1:07 pm

If you want low rpm torque you need to think small cam on a tight lsa .108 at most and 270 adv duration. If i were towing i would go 106 and 262 to maximize torque at 2500 rpm

Post Reply