Late model 350 SBC Question - Hot Rod Forum : Hotrodders Bulletin Board -- 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
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 02-19-2005, 08:05 PM
Registered User
Join Date: Feb 2005
Location: Salt Lake City
Posts: 3
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Late model 350 SBC Question

I'm fairly new to SBC being originally from the UK where gas is wayyy to expensive, so please bear with me.

I'm not new to engines, just V8's!

Ive been given a late model (1989) SBC in good working order.
Plan is to rebuild it as a replacement for my leaky SBC thats sat in my 84 Blazer.

After the teardown the short engine is in perfect order but one of the heads is cracked.

Do I have to hunt down late model heads or can I use ones from an earlier SBC?

I know 'something' changed in 1987 as regards the SBC but I struggle to find a definative answer, even on the Net.

Suggestions on reliable mods during the rebuild would also be most appreciated.

Thanks in advance.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 02-19-2005, 08:40 PM's Avatar
Last photo:
Join Date: May 2002
Location: Holly, michigan
Posts: 8,990
Wiki Edits: 0

Thanks: 88
Thanked 541 Times in 470 Posts
Two major things happened in 87 for the SBC heads. The heads were redesigned to take different valve covers, and the center two intake bolts on each side were drilled at a different angle. This makes intakes from earlier engines hard to use unless they can be modified. Many early intakes are just slotted and used with an angled washer to bolt on later heads.

The other modification was the one piece rear main seal on the block. This requires a different flywheel and block related parts. Many blocks were also cast and partially machined for roller cam setups. These cam and roller lifter blocks became more common in the ninties.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 02-19-2005, 09:27 PM
Registered User
Join Date: Feb 2005
Location: Salt Lake City
Posts: 3
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
So if I use early heads I can use early intakes and with the earlier valve covers?

I had a set of 400 SBC heads given to me and wondered if they would be suitable.

I know one difference is the steam holes but thought maybe they would need some machining as presumably they have bigger combustion chambers due to the larger displacement.

Would it be a better bet to buy a 383 stroker crank for the 400 heads or stick with the 350 displacement and buy/find some better heads?

I'm hoping to use TPI btw.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-19-2005, 10:12 PM
NAIRB's Avatar Moderator
Last photo:
Join Date: Sep 2002
Location: cimarron, ks
Posts: 1,658
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
The 400 heads would be preferred over the TBI style heads. You more than likely have 193 castings on your 89 model 350. These heads are very crack prone on the center two exhaust seats, cracking into the heat risers. The 89 model heads are 64 CC combustion chambers, but have very restrictive swirl intake ports, making them a poor performance choice.

On a budget, I would work the 400 heads over, treating them to a pocket port, a flat mill and deck the block to gain a little compression. You could put a small knuckle on the piston to try and achieve around 9.5:1 compression.

Common 400 head casting numbers can be found at, 493s were common. The early 400 heads are good, heavy duty castings, and offer large ports, and can be made to flow some decent numbers. Just use the 350 gaslet to block the steam holes.

A good alternative would be opting for the World S/R 67 CC heads or Dart Iron Eagle SS head.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


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
SBC Question 400 block Jag Daddy Engine 41 06-18-2007 08:31 PM
350 SBC timing question Magikal Engine 4 02-18-2004 09:55 PM
Cam grind for a 350 sbc 30coupe Engine 2 04-07-2003 07:29 PM
question on starting a 350 sbc stfinney Engine 8 02-20-2003 09:24 PM
Tranny question to my sbc BillyBob1950 Transmission - Rearend 1 01-24-2003 02:49 PM

All times are GMT -6. The time now is 07:17 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.