smog 350, more power? - Page 2 - 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
  #16 (permalink)  
Old 06-19-2013, 07:57 PM
BigEd36's Avatar
Registered User
 
Last photo:
Join Date: Nov 2009
Location: Auburn, IN
Age: 65
Posts: 389
Wiki Edits: 0

Thanks: 19
Thanked 43 Times in 39 Posts
Daedalus, with the typical SBC dished pistons used in the "smog era" engines and the 64cc heads you will be basically equal to the piston/chamber cc combination of the L31 vortec long block recommended by Oldbogie. It's also equal to the setup used in the GMPP 350 HO (350 cubic inch 330 HP) and CT350 (Circle Track 350 cubic inch 350 HP) crate engines (which both use the L31 vortec heads). You should be about 9.4:1 static CR. Make sure to use a head gasket that will give you about .040" quench. You will have the advantage of a bit larger ports and a little more aggressive cam, so you should have no problem hitting 350 HP. The cam you've chosen will work well with that compression ratio.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 06-19-2013, 08:32 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 806
Wiki Edits: 0

Thanks: 91
Thanked 60 Times in 50 Posts
Quote:
Originally Posted by Daedalus View Post
ok so Im leaning towards this cam, its a hydraulic roller retrofit.

12-422-8 - XTREME Energy

and these heads. I know they're cheap but Ive read quite a few good things about patriot (now promaxx) so im willing to take the risk.

http://www.summitracing.com/parts/pmx-2169/overview/

do they seem like they will play well together?

one thing i've noticed is the cam says stock springs cannot be used.
I guess ill try and email promaxx for spring specs then confirm with compcams whether they will be ok.
The problem is those heads do not list the spring rate of the springs. If they come with springs then they are probably generic flat tappet cam springs. The springs CompCams suggest for the cam you selected are either:
1) 986 which are dual springs and 322 lb/in spring rate.
2) 897 also dual springs and 370 lbs/in spring rate.

Since spring #2 is a heavier spring, it will get to you higher RPM's before the lifters (1) pump up and/or (2) loose contact with the cam and explode on return.

You can get the entire "K kit" which comes with the cam, lifters, timing set, springs, spring retainers and retainers, and cheap valve seals (throw them away and use positive seals). Of course this is serious cash. You might be ahead money-wise to get those Promax heads bare and buy valves and positive seals since the K-kit comes with everything else.

Of course your battle is not over with the retro-roller cam. You will need:
  • a thrust button (used to prevent the cam from walking forward in the motor)
  • a reinforced timing cover to "receive" the thrust from the aforementioned button (you do have some options here homemade or aftermarket)
  • You will need a new distributor gear compatible with a steel cam (bronze, steel, composite)
  • New pushrods (flat tappet lifters are short, OEM rollers are taller, retro-rollers are the tallest yet). You will need to assemble your motor with the heads, and before you install the intake, you will have to measure for the correct length pushrods (this is especially crucial if you use roller rockers instead of the stamped steel OEM rockers).

So now you see this K-kit is almost $1000 USD, plus all these doo-dads...and now you see why I suggested buying that bare OEM factory roller block for $700 USD! Factory roller cams are cheap and so are the lifters.
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 06-20-2013, 07:53 AM
Registered User
 
Last photo:
Join Date: May 2008
Location: ohio
Posts: 1,459
Wiki Edits: 0

Thanks: 34
Thanked 42 Times in 39 Posts
Why would you want those heads and for little more then a hundread bucks you can have a set of dart shp 180cc aluminum heads with a set of dual springs already installed for hydraulic roller cams? The dart heads flow just as good as any decent 180cc head and would work perfect with your cam. I am running a similar size lunati voodoo roller cam and with my dart shp heads it runs very strong to about 6 grand and has a nice little lope at idle and is very street friendly and I can churp the tires driving down the highway by shifting from 2nd to third gear in my little s10. That's up to you though and the dart heads are usa made and assembled and where excellent quality and as good as any head I have had. I just checked summit and I guess they have went up a little since I got mine and they are around a grand for a set with everything.

Last edited by eric32; 06-20-2013 at 07:59 AM.
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 06-20-2013, 09:00 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,069
Wiki Edits: 0

Thanks: 322
Thanked 783 Times in 749 Posts
I would buy bare castings,quality valves and solid roller cam with complete kit. I like more power than most people,,,,
With a small solid roller the idle is smoother(generally)has a wider RPM range than any flat tappet or hydraulic roller with similar specs.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 06-20-2013, 05:54 PM
Registered User
 
Last photo:
Join Date: Jun 2013
Posts: 20
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by eric32 View Post
Why would you want those heads and for little more then a hundread bucks you can have a set of dart shp 180cc aluminum heads with a set of dual springs already installed for hydraulic roller cams?
thanks, I didn't know about dart heads seems like a good option.

so for the following all up im looking at about $2500USD delivered (shipping is the killer, Id have to get each head and the cams/lifters sent individually to avoid import taxes)

cam, timing chain and lifters
thrust button
wear plate
push-rods
dart heads
head gaskets
head studs
brass distributor gear

as for timing cover ill probably just get the TIG out and reinforce the stock one.
plus roller rockers, there's already some on the motor, Ill have to check the ratio see if i can reuse them.

seems like a decent price for what im doing.
but then again, I can get a GM vortec crate motor (330hp 380ftlb) for the same price, less maybe like $1k-1.5k if i sell my current complete motor...
and id have it in the car in a day.

damn decisions..

Last edited by Daedalus; 06-20-2013 at 05:59 PM.
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 06-20-2013, 06:08 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,069
Wiki Edits: 0

Thanks: 322
Thanked 783 Times in 749 Posts
for less than 6k you can buy a 415 HP/425 torque 350 from a great crate engine dealer,runs on 87 octane
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 06-21-2013, 10:19 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,069
Wiki Edits: 0

Thanks: 322
Thanked 783 Times in 749 Posts
wrong place to advertise
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 06-22-2013, 01:58 AM
Registered User
 
Last photo:
Join Date: Jun 2013
Posts: 20
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
unfortunately 6k is above my budget, I still need money for paint.

im thinking it might be an option to just buy a vortec crate motor, and put the cam i previously mentioned into it. because its factory roller cam block, I wouldn't need to change much would I? just cam and valvesprings? assuming the factory vortec heads can handle the 0.502 lift.
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 06-22-2013, 07:46 AM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 37
Posts: 806
Wiki Edits: 0

Thanks: 91
Thanked 60 Times in 50 Posts
Quote:
Originally Posted by Daedalus View Post
unfortunately 6k is above my budget, I still need money for paint.

im thinking it might be an option to just buy a vortec crate motor, and put the cam i previously mentioned into it. because its factory roller cam block, I wouldn't need to change much would I? just cam and valvesprings? assuming the factory vortec heads can handle the 0.502 lift.
Depending on the article you read, they will state max lift on Vortecs is around .470-.490". So you will need to machine down the valve guides to achieve more lift (at full lift you will need around .060" clearance between the retainer and seal). The valve guides will also need to be machined to accept a positive type seal. You can buy the tools and do this yourself, or have a shop do it.

Keep in mind that the valve guide boss on a Vortec is .845". Instead of using an inner damper spring, engineers relied on this tight fit to damp any oscillations and spring surge with a tight fit inside the spring. Up until the Vortecs, the boss was .785"...so if you go to a dual valve spring, be sure you verify the inner diameter of the inner spring. If needed, you can have a shop machine the boss diameter down to accept a smaller ID, as well as a larger OD outer spring.

This is a pretty good place to start reading on Vortecs.
http://www.crankshaftcoalition.com/w..._cylinder_head

There is also a section in there about the costs of switching to Vortecs.
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 06-22-2013, 08:27 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,069
Wiki Edits: 0

Thanks: 322
Thanked 783 Times in 749 Posts
You said time was important and cost of shipping multiple orders,,,
Thats why I said to get the 415 HP crate engine,(comes with shp heads,retro roller and a warranty)
I would seek out a GM roller block if there are any good cores where you are;
look for a 3.62 stroke crank x 4 inch bore
used roller lifters,the shops here have buckets of them for scrap,gotta be a good set somewhere,
rebuild the short block stock,use good pistons rather than rebuilder pistons,
align hone/square/deck the block,
balance,
heads would be either dart shp/edelbrock e-tec or w/e is best bang for the buck
If you think iron heads are better for the Harry Handcuff problem,then dart has a good couple castings(sportsman)
probably use O.E.M. valves or other decent valve,not chinese.
I would use a .480-.500 lift roller cam,duration and lda to be determined after heads are located and CR figured.
not sure how much you will save in cash and Im sure the time would add up fast and soon bother you?
I would still want north of 400 hp

QUESTION: if the engine you build has a lumpy idle and aluminum heads,is that going to be an issue?,reason,
I figure if you use iron heads,a little less CR and a wide displacement angle cam,you can still get 400 hp and almost smooth idle,running on mid grade fuel.
engine will need headers and good exhaust
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 06-22-2013, 06:48 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,947
Wiki Edits: 326

Thanks: 760
Thanked 1,013 Times in 849 Posts
Quote:
Originally Posted by Silver Surfer View Post
Depending on the article you read, they will state max lift on Vortecs is around .470-.490".
NOW HEAR THIS: MAX LIFT ON STOCK L-31 VORTEC HEADS IS 0.420"
The play that is left over is the safety margin.
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 07-31-2013, 06:51 PM
Registered User
 
Last photo:
Join Date: Jun 2013
Posts: 20
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
first up let me say I appreciated all the help so far, thanks guys.

ok now so I did a bit more to try and figure out what is going on with this engine.

I got a borescope and inspected a couple of the pistions through the sparkplug hole, the pistons are actually flat tops, and have quite a large valve relief, and there is some sort of pitting or carbon build up ontop of the pistons? is this bad? or because its zoomed in it might look worse than it actually is?

the picture shows the part of the piston top with the cuts for valve clearance.
pic1 that dimple thing is the center of the piston top, and you can just see the cylinder wall top left.




the pictures are **** as its a USB borescope on my laptop, but the video card is crap so it wont capture, hence I had to take a photo of the screen with my phone.


the motor makes 160psi (dry) across all 8 cylinders, and shows evidence of rebuild at some stage (block has been skimmed / machined down till the engine number is barely visible), it runs ok but has a very slight misfire, no smoke or audible detonation.

I guess the best thing to do is pull the heads and inspect it further?
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 07-31-2013, 10:06 PM
Registered User
 
Join Date: Jul 2013
Location: Sunnyvale California
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I'm a ford guy but maybe this can help. On my '95 mustang Gt, I swapped the 5.0L for a 393 stroker. It had 10:1 compression, AFR-185 heads, 226/226 @ .050" cam, and a ported intake. It made 365 RWHP and had no issue passing California emissions. That very motor with 8.25:1and 10 pounds of boost from a vortech S-trim made 560 rwhp and burned cleaner than the factory 5.0L.
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
Muscleing Up a 350 Vette Smog Engine 345 desoto Hotrodding Basics 6 03-04-2011 06:38 PM
76' 350 Low Comp Smog Motor - ?'s stumprrp Engine 7 02-02-2010 09:30 AM
350 emmision/smog? countryboytn Engine 8 10-19-2009 06:39 PM
smog diagram 78 chevy pu 350 engine harmon Engine 3 08-31-2008 01:47 AM
smog, smog, smog....CA smog , failed. jakeslim Engine 12 08-20-2005 11:59 AM


All times are GMT -6. The time now is 06:43 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.