Carb spacer input required


Charter Member, Founder Bird-Run, Cruise-In Bird-R
Mar 5, 2008
Anaheim, Ca.
Scott wants me to add a 1" spacer to his set up. It is a 400HP 350SBC.
With this dyno sheet:
And this 750 DP holley carb
And this Edelbrock dual plenum manifold.
Which of these spacers (Inserts)would give the best benefit?
I was leaning towards the open spacer, but now am thinking the 4 holer would be better.
Same AutoZone spacer that I bought.... it keeps the drop base air cleaner bottom from hitting the wire boots on the distributor, other than that I have not noticed a difference between open, 4 holes or no spacer..... oh yes, my wallet is $20 lighter.....
After discussing it with Lars, I believe I am going to use the 4 hole setup. It would appear the open spacer would do more harm than good with a divided plenum. Unless Scott wants to run above 7,000RPM. :nuts:
Bird can't use it because he has a dual plane, and they won't fit on a single plane with a divider. They're for specific manifolds and each one is different but since it's called the turtle I thought I'd mention it here. Who would have thought, a performance upgrade called turtle :D Jim may have something going for him afteral :1st:

I never used one, read about it some time ago.