Square Bore or Spread Bore?
Thread Starter
Racer
Joined: Jan 2004
Posts: 463
Likes: 0
From: South Haven MI
Square Bore or Spread Bore?
Which is better? Square Bore or Spread Bore? I have a spread bore intake (original cast iron L48 intake) with a square bore carb with adapter plate. With the adapter and non stock air cleaner I have slight interference with the hood on my 79. I was thinking of getting an Edelbrock RPM intake (square bore) to mate with the carb and remove the adapter plate. Is this combo a better performer than the stock setup with spread bore?
Instructor
Joined: Aug 2002
Posts: 197
Likes: 22
From: Upstate SC
Re: Square Bore or Spread Bore? (jacobsed)
I've had a spreadbore Holley 650 on my 1970 350/350 since 1973. It was designed as a Qjet bolt on replacement, I believe. It is a much more responsive carb than the Qjet and did not bog and stumble like the Qjet. I realize this is old technology by today's standards but I just thought I'd put in my two cents worth in anyway.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Re: Square Bore or Spread Bore? (70L46Conv4Sp)
I would go fuel injection, but if you must keep the carb I would get a spreadbore for a basically stock or lightly modified car. This will allow some fuel economy benefits. For an all-out bruiser, square bore is probably easier to tune.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Square Bore or Spread Bore? (jacobsed)
The Edelbrock RPM intake will be higher than your stock intake with the adapter.... won't solve your hood interference problem.
