Square bore on a spread bore?
 

Here is my setup.

454 420 hp engines

Factory Merc 365 aluminum intakes which have the dual bolt pattern in them.

Holley 800 double pumpers

I am rebuilding the carbs because of blown power valves.

My question is, am I ok running these intakes or should I ditch them for true square bore intake suck as the Edelbrock Air Gap or similar? I just bought the boat so I cant say how it ran before with the stock merc intakes. Thanks

Re: Square bore on a spread bore?
 

I would change them. Ive always heard they hurt airflow bad. Never tried it myself though.

Re: Square bore on a spread bore?
 

Actually, I was told by a few engine builders here on the board that the 454 Mag intake is a pretty good intake. Compare it to a Team G dualplane, very similar. I was also told to use an 1 1/2" spacer.

I didn't think the other bolt holes lined up with the Holleys that I put on this winter. (maybe they did and I missed something) I used an 1 1/2" adapter.