Pontiac - Street No question too basic here!

          
 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #9  
Old 12-30-2011, 08:17 PM
77 TRASHCAN's Avatar
77 TRASHCAN 77 TRASHCAN is offline
Ultimate Warrior
 
Join Date: Oct 2008
Location: 31May2013 Temporary home to the world's widest (that we know of) tornado. Lord, NO more Please...
Posts: 6,750
Default

Hey Steve,
I keep thinking of this thread. You might be asking a question about doing something that's seldom been done...
The ideas presented sound good.

Jim Hand says the port volume of most 68-up "D" intake ports is close to the same. I'm guessing a set of 6X-8's might be the ticket for this potential build?, knocking off the sharp edges in the ports, keeping the port volume as small as possible for port velocity, comp. ratio of a little over 9:1. zero decking the block for utmost combustion effeciency.

I used a Sealed Power CS641 (duration @ .050 198 degrees, intake, 208 degrees exh, LSA 111 degrees) cam in the 350 that currently resides in my 77 T/A. Sealed Power lists it as a replacement for the 066 and 067. It gets fair MPG, but I've never spent enough time on it to try improvements. I bought a SP2P to try on the 350, and have a regular performer I plan to try also

My T/A got excellent MPG when stock (stock as in COMPLETELY stock, I removed the cat converter,only). 21 MPG was not uncommon, Got 22 MPG several times. All this WITH the EGR functioning...I like the idea of using a larger torque engine (couldn't think of a much better one than a Pontiac!!!), and lugging it out on the highway getting the RPMS low enough to hopefully get some decent MPG #'s...
THe stock cam in my T/A was a teenie weenie cam (which developed a flat cam lobe @ around 60-70,000 miles) Sealed Power has a replacement cam for the small cam, also, it's a CS690, .364" gross lift. My car ran very well with this cam, I think it's the same cam (spec wise) you have in the 265.

I sold 3 Comp Cams 260H cams, (these are NOT the XE cams) in the good old days when I sold auto parts. The cams I sold went in 77-78 T/A 400's. Everyone liked how their cars ran after the switch. I wonder... about that cam for a 455

I'm curious what others say, especially concerning cam selection, comp ratio. With the ability to tune a Q-Jet so finely (thanks to Cliff!!!) I think some good results are around the corner.

I want to try a MPG oriented 400 in my T/A. MY car currently has the 2.41 gear in ti w/ the 350 engine. I have a TH350 lockup from a 81 turbo T/A, it would knock the RPM's down another 300-350, putting in in the range of your setup. I'm loosening my strangle hold of not caring for O.D. tranmissions after reading Cliff's book on them...(may never own one, but...)

I wonder about the use of stock exh manifolds. A 455 has a pretty fair amount of air flowing through it. Don't want to choke it, but the volumetric effeciency is at a low RPM, stock exh manifolds might be the ticket...

Steve, I pray for a great 2012 for you, lookng forward to seeing this build!!!
Jeff

__________________
1977 Black Trans Am 180 HP Auto, essentially base model T/A.
I'm the original owner, purchased May 7, 1977.

Shut it off
Shut it off
Buddy, I just shut your Prius down...
 


Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 05:03 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017