Intake manifold for a big block
Heel & Toe
Joined: Jul 2018
Posts: 21
Likes: 3
From: Fayetteville, NC
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,095
Likes: 4,449
From: Marlton NJ
I heard an alum Torker !!, a 71 Alum LS6 rectangular port one, and a 69 427 390 oval port alum one, and the 70-72 LS5 cast iron oval one. Nothing with any height to it. Even then a 2 inch drop stock base type air cleaner base is required/suggested. The intake height number I have in my notes is 3.6-3.8 inches. From block rail to intake platform.
Most performers, Chevelles, BBC, L88 etc are about 5.0+ inch
Hope that helps.
Most performers, Chevelles, BBC, L88 etc are about 5.0+ inch
Hope that helps.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,095
Likes: 4,449
From: Marlton NJ
I saw a diagram explaining how to take the measurements but can't find it now. You had to measure from both the front and the back of the manifold, and average the two to get the carb pad height. IIRC it was from the bottom front lip of the manifold (top of block) up to a ruler set on the carb pad. Same for rear. Then I "heard" some manifolds do not have the proper degrees of tilt of the carb pad for the front air cleaner edge to clear a BB hood.
Leaves one with very few choices.
Also I saw a stock 454, unknown flat? intake, with AC drop air cleaner fit under a stock 72 Vette SB hood. So I don't know how much extra clearance the BB hood actually buys you.
The 73+ hoods definately buy you a little more room, maybe an inch? That may allow enough room for something like the performer?.
If anyone wants a clearance measurement I am willing to provide. 454 currently wearing 73 iron intake.
Leaves one with very few choices.
Also I saw a stock 454, unknown flat? intake, with AC drop air cleaner fit under a stock 72 Vette SB hood. So I don't know how much extra clearance the BB hood actually buys you.
The 73+ hoods definately buy you a little more room, maybe an inch? That may allow enough room for something like the performer?.
If anyone wants a clearance measurement I am willing to provide. 454 currently wearing 73 iron intake.
Le Mans Master
Joined: Dec 2003
Posts: 5,381
Likes: 416
From: N J
I saw a diagram explaining how to take the measurements but can't find it now. You had to measure from both the front and the back of the manifold, and average the two to get the carb pad height. IIRC it was from the bottom front lip of the manifold (top of block) up to a ruler set on the carb pad. Same for rear. Then I "heard" some manifolds do not have the proper degrees of tilt of the carb pad for the front air cleaner edge to clear a BB hood.
Leaves one with very few choices.
Also I saw a stock 454, unknown flat? intake, with AC drop air cleaner fit under a stock 72 Vette SB hood. So I don't know how much extra clearance the BB hood actually buys you.
The 73+ hoods definately buy you a little more room, maybe an inch? That may allow enough room for something like the performer?.
If anyone wants a clearance measurement I am willing to provide. 454 currently wearing 73 iron intake.
Leaves one with very few choices.
Also I saw a stock 454, unknown flat? intake, with AC drop air cleaner fit under a stock 72 Vette SB hood. So I don't know how much extra clearance the BB hood actually buys you.
The 73+ hoods definately buy you a little more room, maybe an inch? That may allow enough room for something like the performer?.
If anyone wants a clearance measurement I am willing to provide. 454 currently wearing 73 iron intake.
I have a performer intake on my BB in my 77.
The solution to closing the stock hood was a choke less carb, along with a drop base air cleaner and a flat, not domed lid on top of it.
No issues, works fine.
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
If you got the $$$, a Tri-Power setup will clear a big block hood.
Also, and EFI setup can let you run a taller manifold since most throttle bodies are about 1/2 the height of a carburetor. Saves about an inch.
Also, and EFI setup can let you run a taller manifold since most throttle bodies are about 1/2 the height of a carburetor. Saves about an inch.
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Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
Not ALL throttle bodies are shorter than a carburetor. I have the Holley Stealth Sniper EFI which looks just like a Holley Double Pumper. It is very close to the same dimensions of the carburetor. If you saw it under a hood you would guess that it was a carburetor as it was designed to be less noticeable.
With the Holley Throttle body on my 1968 C3 (originally a L71) I have had to reduce the thickness of the seal that connects the hood to the Drop base on the throttle body. I have an L88 Hood and it seals nicely and the throttle body is located exactly where the carburetor was supposed to be. Being the same size as a carburetor and looking like a carburetor is why it is called a "Stealth" Sniper.
With the Holley Throttle body on my 1968 C3 (originally a L71) I have had to reduce the thickness of the seal that connects the hood to the Drop base on the throttle body. I have an L88 Hood and it seals nicely and the throttle body is located exactly where the carburetor was supposed to be. Being the same size as a carburetor and looking like a carburetor is why it is called a "Stealth" Sniper.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
My EFI is flows better than the shorter stock tripower since the throttle bodies are shorter and the manifold taller. One day, I may sell it and swap to a single 4bbl EFI. Till then, I'll just enjoy it.
