motor mount sb vs bb difference???

jsssgrl1209

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Location
hegins PA
I have an 1981 Corvette. I changed the motor from the 350 small block over to a 427 big block. My issue that I am running into is hood clearance problems. The engine has a edelbrock o66 dual quad intake and it has 2 1/2" thick nitrous plates mounted under the carbs.

I currently have 2 air cleaner settups for the car. The first is in the picture. They are (2) proflow eldebrock aircleaners, I cut and modified to clear the hood and fit together.

I really dont like the look of them and switched to (2) 6 1/2" round X 1 1/2 height air cleaners.
I have the element directly on the carb with no base plate which works fine but, it still touches the hood.

The hood is a cowl induction stinger hood, about 2 1/2" of added clearance. The car ran fine with the proflow aircleaners but are these 6 1/2"small air cleaners a bad choice to use on such a big engine? or will they work fine? I have the car up on blocks in my garage waiting for my 6 speed transmission to get rebuilt so I havent got to drive it with the smaller air cleaners.



Is it possible I have the wrong motor mounts?? I reused the stock small block mounts on my vette.

I though all small block and big block mounts were the same?
thum_11074a5bbe1f99b5a.jpg

Any help at all is appreciated.
 
I had the C66R intake with the 2 carbs on my 69 when I got it and the 2 round air cleaners fit under the hood no problem. It was close, but it fit. I don't think there's any difference between either the frame mounts or the motor mounts between a SB and a BB. I changed both mounts to Poly and the only question was are they thick mounts or thin ones. I have thin mounts I think the poly is 5/8 0r maybe 3/4 thick, and there is a 1/4 "shim" plate under each mount to the block. If you look in my pictures you can see the hood better, or:

DSC00146.jpg
 
you arent running the nitrous plates

You have the same intake and carb settup, but I have the (2) 1/2" thick nitrous plates under the dual carbs. That is what is killing me..

If I take them off I will be able to make everything fit with about 1/4" to spare. But I really dont want to remove them.

What size round filters did you use??? Where they the small 6 1/2" by 1 1/2" tall?? How did you car run with them on? I am afraid of the small airfilters that I will be choking out my engine.

If all else fails I mightbuy a butterfly flap hood scoop and end up cutting the hood.

Just not sure how that will look with the air cleaner sticking out of a stinger hood. Probably pretty dumb. Decisions decisions.
thum_11074a5d073ff2f4b.jpg
 
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I was feeding a 454 thru those little round filters and it never did run out of air. I ran out of air before the motor did. In this case, me running out of air is really me running out of cajones.
 
I was feeding a 454 thru those little round filters and it never did run out of air. I ran out of air before the motor did. In this case, me running out of air is really me running out of cajones.

Woose, too much HP for you?? Mr. Jet Engine mechanic????


:harhar::stirpot:
 
K&N info

I was told by tech support ar K&N Air filters, that they sell the same size air filter as the 6 1/2 paper filters I am running now.

Their filter is supposed to flow more than the paper ones. They are made of a different material entirely.

The cfm flow they gave me for the filters were 189cfm. Now times that by 2 for the carbs and it equals...... 378cfm..... which is way too low for my engine.

He said my filter cfm flow should be around 800. I asked him what would happen if I did run these and he told me I would be running very rich at 4000+ rpm. Too correct the problem I would have to down jet the carb, but that would just cost me horsepower.

Did you have any jetting issues running your filters?
 
No issues that I know of. But I never made much more than a quick trip up to 7000 and came back down fairly quickly. If I was planning on all day at 6500 then I'd maybe pay some attention to overall airflow.
 
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