350 vortec horsepower - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 03-20-2011, 01:18 PM
Registered User
 
Join Date: Mar 2011
Location: Brook IN
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
350 vortec horsepower

I just bought a 1998 350 vortec it came out of a 1500 i have three questions 1. i think it will but will it bolt right in to my 1990 2500 with a 350 in it
2. im looking to get about 400 horsepower out of it whats the best way to do that
3. when i get it all rebuilt whats the best break in procedure
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-20-2011, 06:20 PM
spinn's Avatar
More dogs than bones
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,212
Wiki Edits: 0

Thanks: 0
Thanked 67 Times in 65 Posts
Buy a package system. Summit has a Heads, cam, intake, gaskets, package for $1300 that claims 400+ hp. The Holley systemaxII claims 410hp, the RPM advertises 430hp. These are ready to bolt on speed kits, and go fast.


Check out the knowledge base section on breakin. Prime with 30 wt non syth, check for leaks at rockers and maintain oil pressure with pump primer , find the oil leaks as they happen , after a heat cycle or 2 the bolts need retorquing, twist the ignition distributor base with a sparkplug attached to confirm spark, cold time engine 10 before TDC, wet intake and throttle plates, Crank it up. Fluctuate idle 2000-3000 rpms with an apropriate setup of baseline carb setting, 20 mins of this, headers turn red and adjust timing and idle circuit, and valves or something like that.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-20-2011, 09:20 PM
cool rockin daddy's Avatar
1.21 giga-watts???!!!!
 
Join Date: Aug 2003
Location: wherever cool cars are
Posts: 1,535
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
Its already a Vortec so you have the Vortec heads. Stab a Comp Cams XE274 or equivalent into it (its a roller engine so many choices), put GM beehive springs or machine valve guide bosses on head to accomodate higher lift of cam, get an Edelbrock RPM vortec manifold, 750 carb of your choice. Headers, of course. Easy 430-440 HP.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-21-2011, 07:50 AM
Registered User
 
Join Date: Mar 2011
Location: Brook IN
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
is the cam a hydraulic flat tappet or roller?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-21-2011, 09:07 AM
cool rockin daddy's Avatar
1.21 giga-watts???!!!!
 
Join Date: Aug 2003
Location: wherever cool cars are
Posts: 1,535
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
You DO know what you bought, right? Your engine is a roller cammed engine. If you read my post you would be looking for a roller equivalent to the XE274. Something with the same duration and lift, give or take, of that cam.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-21-2011, 10:33 AM
Registered User
 
Join Date: Mar 2011
Location: Brook IN
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ya i just didnt know for sure what kind of cam it was
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-21-2011, 11:05 AM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 30
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
Quote:
Originally Posted by cool rockin daddy
Its already a Vortec so you have the Vortec heads. Stab a Comp Cams XE274 or equivalent into it (its a roller engine so many choices), put GM beehive springs or machine valve guide bosses on head to accomodate higher lift of cam, get an Edelbrock RPM vortec manifold, 750 carb of your choice. Headers, of course. Easy 430-440 HP.


sorry to say but your power estimation here is a bit high considering that stock vortecs only flow about 227cfm @ .500", which still is pretty good but not 430-440hp from a moderate cam and 9.3:1 stock compression. other than that you are just about right on with everything else but the hp would be more in the area of 365-390hp (could possibly hit 400) which would put the OP right about where he wants to be. but without some port work done to the stock vortec heads this is about where you want to be. i also think the 750cfm carb is a bit overkill considering the motor wont likely see over 6000rpm. 750cfm carbs are better for a 383-up that will turn 5800+rpm or a 350 that will turn 6500+rpm

my advise would be to tear the motor down, have it honed, re-ringed, new bearings, (new pistons if you want more than 9.3:1 compression). take the vortecs to a decent head shop, have them do the required work to run a cam with higher lift, and some mild port work (these heads respond very well to some minor touch up). check the pushrods, and rockers to see if they can be reused, although i'm not a fan of COMP cams the XE274R is a pretty decent cam, you will have to run an aftermarket stall with it, then look for a set of OE style hyd roller lifters (howards cams make a great set of them for a good price) then look into a 650cfm vac secondary carb, and an aftermarket HEI distributor, new oil pump and water pump and you should be good to go for about 400hp/415tq with a great power curve (you may very likely need to get a shorter set of rear gears as well, nothing less than 3.42's or 3.73's)
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-21-2011, 01:40 PM
327NUT's Avatar
Registered User
 
Last photo:
Join Date: Dec 2004
Location: So. Utah
Age: 67
Posts: 3,178
Wiki Edits: 0

Thanks: 0
Thanked 58 Times in 52 Posts
87Z...I agree with with you except the 650 cfm idea and of course to each his own. I would run a well built Holley 3310 750 vac. sec.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-22-2011, 01:23 PM
Registered User
 
Join Date: Mar 2011
Location: Brook IN
Posts: 12
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
what pistons come stock in the vortec? dished or flat topped? if dished what volume?
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 03-22-2011, 01:27 PM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 30
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
Quote:
Originally Posted by 327NUT
87Z...I agree with with you except the 650 cfm idea and of course to each his own. I would run a well built Holley 3310 750 vac. sec.

since the OP is likely going to use a dual plane intake then he would probably do fine using the 3310 750 vac sec carb, dual planes are far more forgiving when it comes to using a slightly larger carb. if he were to use the 3310 then he would likely gain a little peak hp but loose a little bit of low end tq (which is want you want for the street, not to mention this is going into a heavy truck so you should build more for low end tq instead of peak hp).

I went to holley.com to use there carb calculator, i plugged in 350cid/ 6200rpm max/ mildly modified/ 4bbl/ NA/ street use

it came up with carbs as low as their 600cfm vac sec, all the way up to there 770cfm truck avenger carb (vac sec). the majority of the carbs you will see though are 650cfm.

my strong suggestions for this build (besides what i have already listed above) are to use a 0-80783C holley 650 vac sec, elc choke, 4150 style carb. then to use a set of 1 5/8" headers instead of the 1 3/4" headers, as these will help to produce a bit more low end tq, and help to make a smoother power curve. true you may loose about 5-10 peak hp (all above 5000rpm) but it will make for a better throttle response, and a vehicle that is more fun to drive on the street
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 03-22-2011, 01:55 PM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 30
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
Quote:
Originally Posted by 1990cheyenne
what pistons come stock in the vortec? dished or flat topped? if dished what volume?

i believe that they are going to be a cast alm piston, and based on the vortecs being 64cc, quench being in the area of .040-.050" then the pistons are about -12cc dished. but the problem with them is that they use a round shaped dish in the piston head, we have later found that a D shaped dish with a flat quench pad has far better burn characteristics which means the fuel burns faster and more completly causing more force and efficincey with equals more power

if you want new pistons then i would suggest these.

http://www.kb-silvolite.com/kb_car/p...tails&P_id=157

KB102, which are a 7cc flat top, which when added to the average .050-.055 quench whould yeld you about 9.75:1 compression ratio. for what you are looking at doing i dont think you would want to go any higher than this.

here is a second set of pistons (probably the ones i would actually use)

http://www.kb-silvolite.com/kb_car/p...tails&P_id=155
KB193, which are 12cc D-cup pistons, these with your average .050-.055" quench will yeld you about 9.3:1,
but here is what i would do, i would tighten the quench area up to about .040 by measuring the clearance between the piston at TDC and the top of the block surface (i'm guessing it's about .015" ish) and then using the correct gasket (.015" + X = .040") about .025" to give me the tighter quench area. the KB193 + .040" quench area will give you about 9.5:1 compression, which for this build i think would be perfect.
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
putting 305 vortec heads on an pre-vortec 350 thor1022 Engine 11 01-12-2011 03:17 PM
Vortec head horsepower Bracewell Engine 6 10-15-2010 09:15 PM
im converting a 96 350 vortec and putting in a 99 454 vortec rkoontz93 Introduce Yourself 1 05-11-2010 03:26 PM
Identifying Vortec from non-Vortec engines? RDR800 Engine 4 07-07-2006 08:09 PM
Horsepower.... and horsepower loss PonchoTA79400 Engine 3 03-13-2004 09:25 AM


All times are GMT -6. The time now is 11:18 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.