double hump rebuild - Team Camaro Tech
Engine General Engine Discussion.

 
LinkBack Thread Tools Display Modes
post #1 of 6 (permalink) Old Oct 16th, 05, 07:14 AM Thread Starter
Senior Tech
 
Join Date: Sep 2003
Location: Richmond, VA
Posts: 162
double hump rebuild

I am getting a set of 1.94 double humps rebuilt for a weekend driver, no heavy abuse. Could I just put bigger valves in to increase intake to 2.02 or do I need machine work?

As far as valves/springs etc. should I get original or are there newer components to increase driveability, h.p., reliability etc.?

What shouldit cost to get this done at machine shop?

Thanks all,

Bluesdog
bluesdog is offline  
Sponsored Links
Advertisement
 
post #2 of 6 (permalink) Old Oct 16th, 05, 07:29 AM
 
Join Date: Apr 2005
Posts: 270
Re: double hump rebuild

You just can,t put 2.02 valves in you have to open them up for it.

If you really want it done wright you will also need to do the chamber wall and the bowl area.

If you do every thing wright new parts Using Gm studs and guide plates new springs up grade for harden seats.

I just bought a set of 291 and did all the work to change them to 2.02 and 1.600 including everything listed above it would have cost some one $1,500 to do all the work if they had to buy castings to.

Last edited by Rogers Performance; Oct 16th, 05 at 07:45 AM.
Rogers Performance is offline  
post #3 of 6 (permalink) Old Oct 16th, 05, 12:13 PM
 
Join Date: Apr 2000
Posts: 21,341
Smile Re: double hump rebuild

GM plunge cut the chamber walls around the valves and if you can look at a pair of factory big valve heads, you can see and feel it.

And like said, they won't flow as good as medium valve heads w/o the plunge cuts b/c of too much shrouding next to the tall chamber walls.

You will see what I mean...

pdq67



pdq67 is offline  
 
post #4 of 6 (permalink) Old Oct 17th, 05, 04:27 AM
Gold Lifetime Member
Alex
 
Join Date: Jun 2005
Location: Capitola Ca.
Posts: 838
Re: double hump rebuild

Save your money! It will cost you way more than the heads are worth to change the valve size. Buy a set of Darts or something like that. Even the S/R Torkers will give you the same or better power than GM double humps. I see them on EBay for about $600. New and fresh. I was going to change a set of 186 heads from 1.94s to 2.02s and the machine shop wanted like 800-900 to do all the stuff needed. But that was doing everything, cutting them for larger springs, screw in studs, guideplates hardened seats etc. I bought some new Dart Iron Eagles for $909 shipped to my door off EBay. Way better heads for less money! The only way I would blow that kind of money on a stock set is if they were correct for your car or something like that. Save money and buy someone Else's past mistakes for less!
dragsterman is offline  
post #5 of 6 (permalink) Old Oct 17th, 05, 06:01 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,077
Re: double hump rebuild

bluesdog, you know you will loose some low end torque by going to 2.02. A Z needed that size because the motor ran such high rpms. For street use on a midrange engine 1.94s work just fine. Then all you need is a normal head rebuild (less $$). BTW, What are the casting numbers and date codes of those heads?

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #6 of 6 (permalink) Old Oct 17th, 05, 02:46 PM Thread Starter
Senior Tech
 
Join Date: Sep 2003
Location: Richmond, VA
Posts: 162
Re: double hump rebuild

Kevin, they are the 3917291 casting numbers and the date codes are B-27-8 and B-29-8, athough my car is later year 68. Been manaflixed and cleaned. Studs holes are screw type.

Thanks to all - I'll probably just keep them 1.94's and save cash for something else.

Bluesdog
bluesdog is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
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.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Double hump heads spark plug Q Kyson Engine 9 Aug 21st, 05 11:14 AM
Double hump heads? Hobbes9112 Performance 87 Dec 24th, 04 07:07 PM
Double hump heads 1990SS454 Engine 4 Nov 26th, 02 03:34 PM
double hump heads?what do i have David Bryant Engine 6 Apr 22nd, 02 10:30 AM
Are these Double Hump heads? Old School Tech 2000 3 Aug 8th, 01 10:50 AM

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

 
For the best viewing experience please update your browser to Google Chrome