67 BB Engine clearance to hood?

[Mark S.]

Does anyone know the clearance from the top of the air cleaner on a 67 390 HP BB to the underneath side of the hood? The reason I'm asking is that I am considering putting a phenolic spacer under my stock Holley carb because on hot days the carb begins to whistle after the engine gets hot. And there are quite a few hot days in Dallas! I know the whistling is caused by the carb being slightly warped and I've had it worked on more than once but the whistling hasn't gone away completely. The whistling isn't as bad as it used to be but I would like to try this inexpensive solution if there is enough clearance. FYI, the phenolic spacer is 1" thick.

Thanks,
Mark
member #34132

[Guest]

Re: 67 BB Engine clearance to hood?

I have a 66 Big Block. The clearance with original manifold was a little under /4 Inch. I don't th9nk the spacer will work. Put some clay on top of carb stud and close hood. Use this to measure gap.

[Mark S.]

Re: 67 BB Engine clearance to hood?

Hi Eric - I just did as you suggested and placed some clay on the back top of my air cleaner and closed the hood. To my surprise the clay measured just under 1 1/4". I performed the measurement a couple of times just to make sure. I'm still not too comfortable putting the phenolic spacer in though because the engine rocking back and forth may take up the rest of the under 1/4" clearance and hit the underside of the hood. I might grind the spacer down to 3/4" to give me a little more play. Thanks - Mark

[Douglas L.]

Re: 67 BB Engine clearance to hood?

Mark,

Regarding the whistling, try opening up the secondary throttle plate a little bit.

Doug Lee

[Mark #28455]

try the factory shield

I think the original use was on the California BB cars in 1970 or the LS6- it was an aluminum shield with a 1/4" thick fiber gasket to insulate the carb from engine heat.
Mark

[Kieran A.]

Re: 67 BB Engine clearance to hood?

Mark,I had the same problem on my 1967 L-79. It would only whistle when the engine reached operating temperature on a hot summer day. The problem was warpage of the throttle body plate due to the studs being located at the far corners in combination with the extreme heat on the aluminum intake manifold. After numerous tries the final fix was putting two stock gaskets on together; the extra thickness took up the space even when the engine was hot and there was no change in appearance( Look at a gasket after it has been installed to see if the areas around the studs are crushed while the center base area is still the original thickness)... Just a thought. Kieran #11373