Looking for help on 305 SBC - 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> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-14-2012, 12:17 PM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Looking for help on 305 SBC

Hi all,
I have a '74 260Z (roadster conversion) with a '79 305 sbc 361979,
small dbl hump heads (9370), Weiand intake, 650 cc edlebrock 4 bbl,
Stock lower internals.

Had a 4spd saginaw which I pulled and replaced with a 5spd. Tremec.

Have not been inside yet so assuming cupped pistons and all stock internals. Looking for lowest cost way to get 6000 rpm with whatever
results in HP gain. Now get 15-18 mpg so looking to gain here also.Intend to do valves, (has infrequent oil smoke after idle) so assuming seal leakage. Also has stock cast iron headers which I think should be replace with ss shorties. I have some clearance issues at collector pipe under car to deal with.

Car only weighs in at about 2300 so not looking to go HP crazy.
I'd like to do this over the winter to get readh for Spring season.
Any help you can offer by way of available parts and ideas would be
greatly appreciated. Located in CT.
Jack

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-14-2012, 02:09 PM
gearheadslife's Avatar
MentalMuffinMan
 
Last photo:
Join Date: Nov 2012
Posts: 2,217
Wiki Edits: 0

Thanks: 108
Thanked 284 Times in 266 Posts
you really need to know what size valves those heads are running.. the 305 is limited here..
reg vortecs with 1.94/1.60 valves you have to notch the cyl to clear.. even at modest valve lift...
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-14-2012, 02:56 PM
Registered User
 
Last photo:
Join Date: Jan 2010
Location: North Carolina
Posts: 61
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
do u still have that 4 speed?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-14-2012, 04:48 PM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
help on 305 sbc

Quote:
Originally Posted by gearheadslife View Post
you really need to know what size valves those heads are running.. the 305 is limited here..
reg vortecs with 1.94/1.60 valves you have to notch the cyl to clear.. even at modest valve lift...
Not intending to change headers, intake or carb. Heads are small dbl hump, i'm told 9370, but can't find any listing of that head. Car was del.
in Canada and original owner did work using Canadian GM parts. block cast # GM 361979. i'M told these were used on z28 and the like apps. in Canada and sold over the ctr. as LT-1 heads in US. I can only find listing for 3370 heads, also HP heads. We'll measure everything once inside but I'm assuming at this point everything is junk stock inside.

Where to go without going crazy?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-14-2012, 04:59 PM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Looking for help on 305 SBC

Quote:
Originally Posted by southernculture View Post
do u still have that 4 speed?
I do. With the 3.7 something rear car was screamin on the hwy. also had
trouble getting into reverse when warm. This was a clutch problem .... slave was too close to headers and no heat shield. Tranny was fully rebuilt prior to my buying it. I never tried it, however with new clutch as the new Tremec went in at same time. Use an adjustable dune buggy slave with ford clutch. All is well now. Currently Saginaw is in the shop waiting for the right app. to come along.
Jack
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-14-2012, 06:18 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 7,827
Wiki Edits: 0

Thanks: 313
Thanked 749 Times in 720 Posts
low cost and 6,000 rpm in the same sentence?
you did not say what you have on the engine already and what RPM it works best?

you have what could be a truly fun car to drive,especially with a zingy mouse and 5 speed. I would use a short stroke small block with a moderate solid lifter or solid roller cam
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-14-2012, 07:17 PM
327 / 350 hp's Avatar
Registered User
 
Join Date: Jan 2009
Location: N.F.L.D. Can Argentia
Posts: 182
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
help with 305 SBC

Hi Jack,, those 370 heads are an over the counter head GM used.. I have a pair on my 350,,,194/150,, they are good heads and got the bolt holes.. late 70s head .. Good Luck jim
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-15-2012, 12:26 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by Jack Durand View Post
Hi all,
I have a '74 260Z (roadster conversion) with a '79 305 sbc 361979,
small dbl hump heads (9370), Weiand intake, 650 cc edlebrock 4 bbl,
Stock lower internals.

Had a 4spd saginaw which I pulled and replaced with a 5spd. Tremec.

Have not been inside yet so assuming cupped pistons and all stock internals. Looking for lowest cost way to get 6000 rpm with whatever
results in HP gain. Now get 15-18 mpg so looking to gain here also.Intend to do valves, (has infrequent oil smoke after idle) so assuming seal leakage. Also has stock cast iron headers which I think should be replace with ss shorties. I have some clearance issues at collector pipe under car to deal with.

Car only weighs in at about 2300 so not looking to go HP crazy.
I'd like to do this over the winter to get readh for Spring season.
Any help you can offer by way of available parts and ideas would be
greatly appreciated. Located in CT.
Jack
The obvious answer to more rpm/power is a cam swap. In your case this shouldn't present a problem w/a loss of some low end torque, given the flyweight and rear gear ratio to get it off the line even w/less torque than a stock 305.

I would look into a cam from the Voodoo series by Lunati. They have a fast ramp so the power under the curve is good,and will give you more lift w/o excessive duration. You really need to know the static CR to choose the best cam, though.

The valve springs should be changed to a compatible spring for the cam you choose. Headers are a must IMHO. Even shorties will be a step up.

You will want to recurve the distributor to match the cam.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-15-2012, 10:12 AM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by vinniekq2 View Post
low cost and 6,000 rpm in the same sentence?
you did not say what you have on the engine already and what RPM it works best?

you have what could be a truly fun car to drive,especially with a zingy mouse and 5 speed. I would use a short stroke small block with a moderate solid lifter or solid roller cam
One can only ask ...... using the same block, heads, carb I figured that
cam, valves/springs, better headers (already has custom ss free flow exhaust), and the number of parts floating around the HR WORLD, it is an
achievable goal. Maybe if get lucky on parts being available. I know of a
mustang currently in the shop that's detuning for sake of daily drivability.
Had it been a Chevy, who knows what might turn up.

Time is not my friend, however, as I want this done this winter and the
right combination is a must.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-15-2012, 10:22 AM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by 327 / 350 hp View Post
Hi Jack,, those 370 heads are an over the counter head GM used.. I have a pair on my 350,,,194/150,, they are good heads and got the bolt holes.. late 70s head .. Good Luck jim

That's what I was told. I know there are better heads out there now, but
since I'm not looking to get the max. out of this engine my thinking is they are fine with the right cam/valve/spring combo. I'm guessing should be easy to get 300+ ponies, higher rpm's and better mpg. with these mods.

Anyone have thoughts on this would be appreciated.

I'm used to high rpm engines, (jag 12, por. 928, original modified Z (8000), so going back to 5000 rippms cramps my style. Hasn't been since the GTO / GTX days that low end grunt was a mainstay.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 12-15-2012, 10:30 AM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by cobalt327 View Post
The obvious answer to more rpm/power is a cam swap. In your case this shouldn't present a problem w/a loss of some low end torque, given the flyweight and rear gear ratio to get it off the line even w/less torque than a stock 305.

I would look into a cam from the Voodoo series by Lunati. They have a fast ramp so the power under the curve is good,and will give you more lift w/o excessive duration. You really need to know the static CR to choose the best cam, though.

The valve springs should be changed to a compatible spring for the cam you choose. Headers are a must IMHO. Even shorties will be a step up.

You will want to recurve the distributor to match the cam.

Why do you feel torque will fall below stock? Your correct that the lbs:hp
ratio will be more than sufficient in this application. I'm assuming everything under the heads is stock by seat of the pants, curve peaks early, high 4's to 5K. Car goes pretty good and sounds real nice but lacks that special umph it should have with a V8 CONVERSION. Are you saying the fast ramp/low duration combo is the compromize?
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 12-15-2012, 10:35 AM
Registered User
 
Join Date: Dec 2012
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
help on 305 sbc

Quote:
Originally Posted by Jack Durand View Post
Why do you feel torque will fall below stock? Your correct that the lbs:hp
ratio will be more than sufficient in this application. I'm assuming everything under the heads is stock by seat of the pants, curve peaks early, high 4's to 5K. Car goes pretty good and sounds real nice but lacks that special umph it should have with a V8 CONVERSION. Are you saying the fast ramp/low duration combo is the compromize?
I'd like to thank all those who have commented thus far. This is going to be the area of concentration this year and time's awastin. I'll look into every and all ideas you guys can offer until I come up with something doable. Progress will be posted. Best, Jack.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 12-15-2012, 10:58 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by Jack Durand View Post
Why do you feel torque will fall below stock? Your correct that the lbs:hp
ratio will be more than sufficient in this application. I'm assuming everything under the heads is stock by seat of the pants, curve peaks early, high 4's to 5K. Car goes pretty good and sounds real nice but lacks that special umph it should have with a V8 CONVERSION. Are you saying the fast ramp/low duration combo is the compromize?
Not saying the bottom end tq will be below a stock 305, just saying it wouldn't much matter even if it were.

Compariatively speaking, a faster cam lobe giving the same lift as a longer duration cam will give more power under the curve, better vacuum, etc. The downside is cam break in is uber critical. A roller cam would be a better alternative to a flat tappet, but if that's not in the cards the FT Voodoo is the next best thing in my opinion. Others may recommend the Comp XE series, basically the same type cam, maybe a little faster lobe depending on the exact cam.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 12-15-2012, 04:31 PM
Member
 
Last photo:
Join Date: Feb 2004
Location: N Ga.
Posts: 272
Wiki Edits: 0

Thanks: 3
Thanked 5 Times in 5 Posts
I put a 305 in my TR-7, Surprisingly enough it had flattops with eyebrows. Our '85 pontiac (305) also has 'em.
What I did to the one in the TR-7 was to install a set of big valve heads, with edelbrock manifold, and Carter WCFB, and an oddball Comp cam, but it worked well. I don't remember the grind, I've got the spec sheet somewhere. The guy at the supply house called it a "borderline" cam, It hit a good lick, but didn't have to use a special torque converter. It liked about 1000 rpm for idle, but sounded like about 400, and had a pretty good "zip" to it for a small bore long stroke, put it in gear and idle would drop to about 850. All I was after was a good lick, any stock V8 would make that car a handfull. And you could balace a nickle on the air cleaner at idle in gear.

The 305 in the Pontiac is down for rings and bearings right now, as it has over 300,000 miles on it. After pulling it apart, I was surprized to find flattops with eyebrows. No ridge to speak of, and plenty of babbit on the bearings. I had figured on having to punch it out, and turn the crank. But not needed. I'll post pics of the bearings and bores in another thread.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 12-15-2012, 04:35 PM
Member
 
Last photo:
Join Date: Feb 2004
Location: N Ga.
Posts: 272
Wiki Edits: 0

Thanks: 3
Thanked 5 Times in 5 Posts
Quote:
Originally Posted by Jack Durand View Post
That's what I was told. I know there are better heads out there now, but
since I'm not looking to get the max. out of this engine my thinking is they are fine with the right cam/valve/spring combo. I'm guessing should be easy to get 300+ ponies, higher rpm's and better mpg. with these mods.

Anyone have thoughts on this would be appreciated.

I'm used to high rpm engines, (jag 12, por. 928, original modified Z (8000), so going back to 5000 rippms cramps my style. Hasn't been since the GTO / GTX days that low end grunt was a mainstay.
If geared properly, a "low end grunt" engine will push that Z car, faster than you want to go. And that's exactly what a 305 is.
If you want High rev get a 283, or 302.
Reply With Quote Quick reply to this message

Recent Engine 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
Looking for 305 SBC help DaveyK Introduce Yourself 4 02-01-2011 04:05 PM
Nitrous on a 305 sbc prettyboyced Hotrodding Basics 3 02-04-2010 08:53 PM
sbc 305 ho question drfantastik Engine 1 09-07-2009 02:37 PM
SBC 305 help aormz Engine 7 07-27-2009 12:02 PM
305 Sbc kringold Engine 57 10-15-2006 09:50 PM


All times are GMT -6. The time now is 07:23 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.