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How a Brodix Consumption Manifold Solved a Main Hood Clearance Concern with a Massive Block Chevy in a 1970 Nova


Over the previous yr or so, I slowly assembled a giant block Chevy for my private undertaking automobile, a 1970 Chevy Nova. The construct was deliberate. I even used a mock-up engine to work out lots of the particulars.

From the skin, all the pieces appeared to measure up completely, though the manifold peak appeared prefer it may current itself as a difficulty. I blindly thought I may get by with trimming the hood’s inside reinforcement panel. However as soon as the engine was put in within the automobile, I discovered it wasn’t simply a difficulty:

There was no manner the inventory flat hood would match—trimmed or not.

Whereas at first look this appears okay, there’s undoubtedly a difficulty right here. The hood received’t shut as a result of the manifold I picked was too tall. (Picture/Wayne Scraba)

The one sensible choices have been: Exchange the hood (which actually wasn’t an possibility), closely modify the consumption, or take away and substitute the manifold with a shorter instance.

For me at the very least, that hood was an important a part of the automobile’s look—no additional flash, canine dish hubcaps, and a flat hood. Only a very Plain-Jane automobile.

There have been a number of choices obtainable (operating the automobile with no respectable air cleaner wasn’t one in every of them), however in the end, swapping the Weiand Observe Warrior consumption to a shorter instance resembling this Holley Strip Dominator is the least difficult. (Picture/Wayne Scraba)

That left the choice of machining the highest off the consumption. Truthful sufficient, however the quantity of fabric I might have wanted to take away proved important (see the images). Lots of welding and machining is required. Nicely over an inch must be faraway from the manifold plenum.

The final possibility was to make use of one other consumption. An consumption swap sounds straightforward, however when you perform a little research it’s not—right here’s why:

As identified within the story, all just isn’t nicely when swapping out intakes. (Picture/Wayne Scraba)

Inventory manufacturing line massive block Chevys have an additional consumption bolt over every pair of consumption ports (two pairs of intakes per financial institution and two additional bolts per financial institution). Numerous aftermarket heads don’t incorporate these additional consumption manifold bolts. Virtually all excessive efficiency (tall) intakes wouldn’t have these bolt provisions both. However then again, the overwhelming majority of decrease profile intakes are geared up with these additional bolt holes.

On this Holley Strip Dominator, you may see there’s an additional bolt gap over every pair of consumption ports. Manufacturing line Chevy massive blocks have this pair of bolt holes on every financial institution. (Picture/Wayne Scraba)

So…why can’t you employ an consumption with the additional bolts on aftermarket heads?

If an consumption gasket for the heads with out the additional holes is laid on the consumption, you’ll rapidly uncover you may see daylight within the space the place the bolt holes exist (try the pic beneath). You’ll definitely encounter an enormous vacuum leak—really, 4 of them.

Most aftermarket heads wouldn’t have the additional bolt holes. Right here’s an consumption gasket for my Brodix BB-3 cylinder heads laid over the Holley Strip Dominator consumption face. Utilizing it this fashion will lead to an enormous vacuum leak occasions 4. Virtually all decrease profile aftermarket intakes manifolds are constructed with this additional bolt gap. (Picture/Wayne Scraba)

It’s doable to repair the “daylight” points on these consumption manifolds. The 4 additional bolt holes over the consumption ports could be plugged by means of welding. Then the manifold face on every financial institution would require machining. Relying upon the talent of the welder, you may also need to machine the highest face of the outdated bolt gap too. In the long run, an expensive proposition.

The answer is a Brodix half quantity HV2016 on the suitable right here. Word the distinction in manifold heights between the Weiand Observe Warrior versus HV2016. (Picture/Wayne Scraba)

Now what?

Nicely, all of it comes right down to a go to to SummitRacing.com. One consumption manifold turns outs to be a extremely good possibility, and that could be a Brodix HV2016. This can be a low profile, twin airplane consumption manifold, designed to be used on rectangular port cylinder heads. Complete peak from the China wall up works out to five.175 inches. The fundamental working vary may be very broad at 3,500-6,800 rpm. It’s not a well known consumption, however even revered engine builder Scott Shafiroff makes use of them for particular purposes.

Whenever you study the consumption face on the Brodix manifold, you may see the bolt gap is gone. The ports are additionally organized in order that the consumption can work on heads with or with out the extra bolt holes. (Picture/Wayne Scraba)

Does it match? Sure! So far as a very powerful problem is worried (total peak), the consumption proves considerably decrease than the Weiand Observe Warrior it changed. Sure, my 565 will definitely lose some energy, however the excellent news is, the hood matches with ease.

Right here’s the identical gasket (for a Brodix BB3 Xtra head) proven earlier, laid up towards the HV2016 consumption. There’s adequate materials to port match to the gasket if you happen to need. (Picture/Wayne Scraba)

The equipment used on the Observe Warrior match and the one actual problem I encountered is that the distributor vacuum advance canister hose now evenly contacts the rear runners. This wee dilemma is well solved by re-phasing the distributor (location) and transferring the plug wires to match the brand new location.

I swapped the entire components from the Weiand to the Brodix consumption. All of it matches cleanly. And if you happen to’re questioning, that gold becoming is definitely an Enderle mechanical gasoline injection bypass valve. I exploit a bypass system as an alternative of regulator at the side of a excessive stress mechanical gasoline pump. (Picture/Wayne Scraba)

Downside solved! For a better take a look at the quick and candy consumption answer, try the images.

Earlier than putting in new gaskets, the quick consumption was put in as a mock up, checking the match. To this point so good. (Picture/Wayne Scraba)
This can be a fender aspect view. There’s no signal of the air cleaner—or the carburetor stud and wing nut for that matter. (Picture/Wayne Scraba)
Ditto with a view from the entrance. Backside line? In case you have a hood clearance problem with a giant block Chevy, the Brodix HV2016 consumption manifold is price a glance. (Picture/Wayne Scraba)

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