427 Intake manifold question
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
They interchange perfectly as far as fit, however the 88`s intake is slightly modified with a open plenum. The same intake is used with the L-78 engines......all are dual plane and aluminum.....excellent intakes especially when port matched
yes they are square port too
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yes they are square port too
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Last edited by Ironcross; Jan 29, 2013 at 12:05 PM.
Team Owner
Joined: May 2002
Posts: 24,459
Likes: 13
From: Phoenix
St. Jude Donor '03-'04-'05-'09
They had different casting numbers, and obviously the tri-powered difference. Rectangular seems to be the common, but looking around, seems the older more HP motors had oval. 
3947801 Aluminum 390 Horsepower 427 engines
3937795 Aluminum 400 Horsepower 427 engines
3937797 Aluminum 435 Horsepower 427 engines
39333198 Aluminum L88 and ZL1 427 engines
3947801 Aluminum 390 Horsepower 427 engines
3937795 Aluminum 400 Horsepower 427 engines
3937797 Aluminum 435 Horsepower 427 engines
39333198 Aluminum L88 and ZL1 427 engines
Race Director
Joined: Jul 2001
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Melting Slicks
Joined: May 2009
Posts: 3,079
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2024 C3 of the Year Finalist - Unmodified
I really don't know all the differences. All the MKIV manifolds are probably interchangeable. Here is an interesting history on Chevy muscle car engines:
http://www.superchevy.com/technical/...y/viewall.html
http://www.superchevy.com/technical/...y/viewall.html
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Race Director
Joined: Nov 2002
Posts: 12,142
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From: Taylor Michigan
polished up, you cannot tell the difference as the numbers would be gone
Race Director
Joined: Oct 2000
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From: Shamong, NJ
There are actually 2 L-88 manifolds, the 67 (3886093), and the 68-69 (3933198). The 3933198 was also used on the 69 ZL-1.
The 427/425 intake is found with 3 different casting numbers. 3885069 for 66-68 427/425's, 3919878 for 68 427/425's and 3933163 and for 68-69 COPO 427/425's. All three of these intakes, were also used on 396/375 engines, and the 163 was also used on the 68-69 aluminum head 396/375's. Obviously, not all of these applications are Corvette.
Besides the modified plenum, there were probably some other minor differences, but the basic intakes are the same. All of them are designed for use with a standard bore Holley, and include provision for an intake mounted choke.
Even though both intakes are rectangular port, I don't think they can be used with the newer "Bow Tie" big block heads.
Racer
Joined: Oct 2010
Posts: 259
Likes: 3
From: Plano TX
Intake
There were a few versions of the L88 intake, the last version being the ....198 manifold. I have one on my '73. It does have an "open" plenum, but not as "open" as others.
It would definitely take a high rise compatible hood.
It would definitely take a high rise compatible hood.