3rd Gen / L98 Engine Tech 1982 - 1992 Engine Related

Will this 350 replace my 305 Carbed? 86 Z28

Thread Tools
 
Search this Thread
 
Old 07-21-2002, 10:15 PM
  #1  
Registered User
Thread Starter
 
teknick2000's Avatar
 
Join Date: Jul 2002
Location: Carson City, NV USA
Posts: 6
Question Will this 350 replace my 305 Carbed? 86 Z28

Ok here is the skinny:
I have an 86 Z28 carbed 305 stock
I also have this remanufactured motor from Recon that says this on the tag:
GM 350 69-79 2 Bolt Main Single Rear Seal
Will my heads work on this? Any other items that will need to be replaced such as flywheel, etc.? I am going to get a new intake manifold (want to ditch the smog), but other than that I want to replace as little as possible. Thank you!
teknick2000 is offline  
Old 07-21-2002, 11:00 PM
  #2  
Registered User
Thread Starter
 
teknick2000's Avatar
 
Join Date: Jul 2002
Location: Carson City, NV USA
Posts: 6
Exclamation

Also, I have heard that my T5 tranny will not handle this kind of output. I have a very tight budget, any one have an idea on how to make this happen. Thank you!
teknick2000 is offline  
Old 07-21-2002, 11:33 PM
  #3  
Registered User
 
jayman350's Avatar
 
Join Date: Feb 2001
Location: Lowell, Ma
Posts: 469
Post

so does this motor have heads or you are planning on using the ones from the 305?

if you need heads the ones from the 305 will fit, BUT the car will run like absolute *** (if it does run at all)

so if you don't have much money, wait.... don't go about it half assed or else you will be nickel and diming it forever and you will never be happy w/ it

check out a set of GMPP vortec heads for cheap heads that perform well

------------------
Jay
black 85 Z28 - waiting on a new paint job, then she'll be real purty
87 Chevy S10 Blazer- 2.8 liters of pure fury

Jay's Website
yahoo im: wildcat856
AIM: Jayman85Z
Homer no function beer well without
check out GMPerformance.org
jayman350 is offline  
Old 07-22-2002, 12:08 AM
  #4  
Registered User
 
stanghunter211's Avatar
 
Join Date: Jul 2001
Location: San Francisco, California United States
Posts: 769
Post

Why would the 305 heads make that 350 run like crap??? GM's ZZ4 motor comes with 58cc heads, and those are the same size as 305 heads. That motor makes like 10-1 compression. I wouldn't put 305 heads on a 350, but I don't see why it wouldn't run??!?! I am planning on doing the same thing bro, only I had planned on using a newer 4-bolt rear main seal 350 block. I have been thinking about just buying a ZZ4 and changing the intake manifold and a few other things. I had thought about the long way around, but that would take too long and might cost a little more money. Plus all the suspension work you need to do on a 3rd gen before you even begin to tackle power. It should be pushing 400 smog legal horses. Which won't be too bad for a car that used to sport 165 Well, good luck man, let us know how it turns out!

Will

------------------
'86 Z-28 305 c.i. LG4
Rochester QuadraJet 4bbl
Flowmaster 80 series Chrome Tips
Dual Snorkel Air Cleaner
K&N Filter
Michellin P215/65/R15 X-Radial Plus
Lots of Mods on the way
Pioneer 4"x6" dash
Pioneer 6"x9" rear
Alpine 8" Type S in bandpass box
Alpine Amp 300x1 bridged
Sony 4000X- x-Plode Deck 50w x4

Soon to be sporting Hooker SuperComp Shorties, CompCam Xtreme 256H, Edelbrock Performer EGR, World Sr Torquer 305's, DynoMax Super Converter, and American Thunder 3" Cat-Back !!!

http://camaroz28.cardomain.com/id/stanghunter211
stanghunter211 is offline  
Old 07-22-2002, 12:25 AM
  #5  
Registered User
Thread Starter
 
teknick2000's Avatar
 
Join Date: Jul 2002
Location: Carson City, NV USA
Posts: 6
Post

The guy I got the motor from told me that Vortec heads WOULD NOT fit this motor (because it was for 69-79?) And yes, for the time being I am keeping the 305 heads. I also went with a single rear seal because I didn't want to replace the flywheel. My biggest concern right now is the tranny. Will my T5 hold up to this motor? Mind you I figure it MIGHT output 250HP max, as it is just a cheap rebuilt. Thank you guys!
teknick2000 is offline  
Old 07-22-2002, 12:38 AM
  #6  
Registered User
 
Scrote's Avatar
 
Join Date: Sep 1999
Location: Southern MN
Posts: 85
Post

The T-5 should hold up fine, I have seen them with 300-400hp behind them and they still are ticking. 250 hp will probably not break anything.

Oh and PS, your 305 heads will run just fine with that 350, If you have flatop pistons your are looking at about 9.5-10:1 some where in there, just fine for 90-93 octain. You will probably get better throttle response as well. If you have the time pull the heads apart and go through them, at minimum replace the valve stem positive seals. A 3 angle valve job and a back cut on the valves wouldn't hurt either.

Take it easy,
Good luck,
Erik
Scrote is offline  
Old 07-22-2002, 02:16 PM
  #7  
Registered User
 
Mark A Shields's Avatar
 
Join Date: Dec 2001
Location: MD
Posts: 6
Post

Um, in '86 it went to 1 piece rear seal, you are trying to use a 2 piece rear seal, just a minor problem. You'll need a different flywheel, that's what I did.

------------------
'86 IROC 350
Edelbrock Headers
Edelbrock 600cfm carb
Hooker cat-back
Rebuilt 700R4
3:73 posi
B&M Megashifter
K&N airfilter
Accel HEI distributor

[This message has been edited by Mark A Shields (edited July 22, 2002).]
Mark A Shields is offline  
Old 07-22-2002, 02:39 PM
  #8  
Registered User
Thread Starter
 
teknick2000's Avatar
 
Join Date: Jul 2002
Location: Carson City, NV USA
Posts: 6
Post

yeah, I have a new flywheel as of today. Thank you though
teknick2000 is offline  
Old 07-22-2002, 02:47 PM
  #9  
Registered User
 
bestracing's Avatar
 
Join Date: Mar 2002
Location: covington, kentucky, US
Posts: 101
Post

<font face="Verdana, Arial" size="2">Originally posted by stanghunter211:
Why would the 305 heads make that 350 run like crap??? GM's ZZ4 motor comes with 58cc heads, and those are the same size as 305 heads. </font>

They have the same size combustion chamber size but usually a 305 head has smaller runner volumn so they flow less than most 350 heads. You need to look up the part numbers to find out what size runner volumn you have and then make a decision from there if you can use the 305 heads or get different heads. The car will run fine with 305 heads it just might not be at the power level you thought you wanted.

The aluminum "Fast Burn" heads will bolt up to older engines. I was looking at getting a set for a 350 I was going to build up until I spun 3 mains. Jim Pace has them for about $1100 for the pair complete with valves, springs, retainers, and rocker studs if you are interested in that route. www.paceparts.com

------------------
Wayne Best
Best Racing
67 rs Camaro
  • 355 cu in Chevy
  • 12.5:1 compression
  • 10.90s @ 120 mph

87 Formula 350 w/388cu.in. motor

www.geocities.com/best_racing
bestracing is offline  
Old 07-22-2002, 02:49 PM
  #10  
Registered User
Thread Starter
 
teknick2000's Avatar
 
Join Date: Jul 2002
Location: Carson City, NV USA
Posts: 6
Post

upon further inspection, I have determind this motor to be a 4 bolt motor. I dont know if this changes anything, but whatever. Thank you again!
teknick2000 is offline  
Old 07-22-2002, 04:26 PM
  #11  
Registered User
Thread Starter
 
teknick2000's Avatar
 
Join Date: Jul 2002
Location: Carson City, NV USA
Posts: 6
Post

heh, I got some 350 heads that are remanufactured (got them from the place that remaned the motor) so that is solved! I also heard that the 350 moght need an oil cooler? It is very hot and dry here, and sometimes I get stuck in stop-and-go traffic. One more thing: I know that there are problems with the stock GM 195F thermostats, what if I bump it down to a 180F or so? Thank you for the input
!!!
teknick2000 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
F'n1996Z28SS
Cars For Sale
8
08-23-2023 11:19 PM
draven666
South Atlantic
0
11-26-2014 07:16 PM
draven666
New Member Introduction
0
11-26-2014 07:10 PM



Quick Reply: Will this 350 replace my 305 Carbed? 86 Z28



All times are GMT -5. The time now is 11:28 PM.