General Discussion Discuss your Oldsmobile or other car-related topics.

Will a 4150 PosiFlow Ruin My Throttle Response? Mild 455 Build

Thread Tools
 
Search this Thread
 
Old December 25th, 2018, 08:22 PM
  #1  
Registered User
Thread Starter
 
generalmopars's Avatar
 
Join Date: Jan 2017
Location: Harrisburg Pa
Posts: 82
Will a 4150 PosiFlow Ruin My Throttle Response? Mild 455 Build

I recently picked up 2 455s, one 69 Toro motor and a 70 98 motor. The Toro is fairly fresh so im just going to leave it stock and dump it in my wagon i recently dropped a decent 350 in. as for the 70, it needs bored so its getting flat tops. The build: i have a bare set of speed master heads, long tubes, a mondello 4150 posi flow intake and a 496\520 camshaft. I hear everybody ranting and raving over the performer intakes, the problem is i dont have a performer so naturally id like to use what i have. will a single plane make the throttle response go down the toilet? Honestly i think ill be just fine but im second guessing my self here.

On another note: this build is for my Stock 68 cutlass supreme, i have a 308 posi for it because i do more highway driving than anything and typical cruising speeds are anything from 70 to 90 mph. i have a few trans options as well, i dont want to use a 400 because im not cutting my drive shaft. i can use the 2 speed that is in it now (not going to), use a beefed up 350 (most likely) or spend money on a built 200 4r (want), figure ill use a 2500 Hughes converter Also i have not decided on a carburetor yet, was thinking something vacuum secondary for sure, maybe an 850 holley. As for exhaust im thinking Cherrybomb Vortex mufflers but probably no H or X pipe and absolutely NO Flowmasters... EVER...

In all honesty, am i really going to lose any thing running an open plenum? i figure its a 455 it should have plenty of torque anyway.
Alright now hit me over the head with your opinions.
generalmopars is offline  
Old December 26th, 2018, 11:28 AM
  #2  
Registered User
 
matt69olds's Avatar
 
Join Date: Jan 2010
Location: central Indiana
Posts: 5,232
In my experience, 455 Olds don’t have a torque curve, more like a torque “plain”. I ran a performer for years, got a smoking deal on a Torker. I didn’t notice any lose in throttle response or low end torque, but did pick up about a tenth on the track. I did need to loosen the wrap on the air door of my Q-Jet to get that gain.
matt69olds is offline  
Old December 28th, 2018, 01:21 PM
  #3  
Registered User
Thread Starter
 
generalmopars's Avatar
 
Join Date: Jan 2017
Location: Harrisburg Pa
Posts: 82
Thank you, i appreciate your response, i guess nobody else wanted to touch on the subject..
generalmopars is offline  
Old December 28th, 2018, 02:06 PM
  #4  
Registered User
 
70W-32's Avatar
 
Join Date: Mar 2013
Location: St. Clair, MI
Posts: 1,639
Originally Posted by generalmopars
Thank you, i appreciate your response, i guess nobody else wanted to touch on the subject..
Not many people will have used a Mondello Posi-flow, its just a Offenhauser intake with name ground off and the price raised. Id go ahead and use it, with a 800-850 vacuum secondary carb. You may lose a bit of off idle torque, but should gain midrage and top end.
70W-32 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Olds luvr
Cutlass
6
April 10th, 2014 05:51 PM
brandon 455
Racing and High Performance
20
June 19th, 2013 06:15 PM
TORTUS
Big Blocks
28
October 18th, 2012 04:50 AM
Creativeindy
Transmission
10
September 15th, 2012 09:59 AM
68conv455
Transmission
8
November 24th, 2007 05:47 PM



Quick Reply: Will a 4150 PosiFlow Ruin My Throttle Response? Mild 455 Build



All times are GMT -7. The time now is 09:20 PM.