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72 6cyl to 396 BB conversion

8459 Views 10 Replies 7 Participants Last post by  Tommy, 
T
Just wanted some opinions.

I'm looking at picking up a good straight 72 which currently has a 6 banger. Currently I've got a 69 SS chevelle in restoration, and have a few big blocks sitting around. I would like to drop in a 396. This car has a muncie 4 speed which someone has put in already.

My question is, would this be worth it to me to do this, as far as resale? And what do I need to make this big block fit? I plan on selling this ride when the conversion is complete, I am also doing a front disk brake conversion to help this ride stop, and converting to a posi rear.

thx
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You will need to get the BB frame mounts so the engine sits in there right. You will also need to modify the heater box to the big block style as well as get a bigger radiator. The radiator support should be cut out to fit the BB radiator so it gets more air flow. If you use an HEI dist. you will need to get the small body type or massage the firewall some to get the stock HEI to fit. You will also need to check valve cover clearance in relation to the brake booster. A BB car will always bring more than a 6cyl car even if it is not original. You will probably want 3:55 or 3:73 gears in the rear to get decent performance.
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T
Do you mean the BB engine mounts? Thx for the info, this will definetly move this along faster.
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I am referring to the frame mounts. They are different for a BB. Then just get the engine mounts for a 69 or 70 nova with BB. The frame mounts are what your engine mounts will bolt to in the frame. On your radiator support look at how it is cut out on the passenger side, then look at the driver side and you will see where to make the cut.
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T
The BB crossmember is different too. The BB frame stands move the engine to the pass side a little. I have read that you can oblong the holes on a SB one to work. The Z bar is also longer on the BB.
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T
Front springs too.
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G
Lets not forget the heater box is different also. You will have to get a 68-70 BB heater box since the 71-72 didn't have the BB option.
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B
If you go to our sister site at Team Camaro and run a search of their archives there on a BBC swap you will get a complete listing of all the modifications with part numbers and were they are available (as well as whose color paint looks the closest to the original et. al.). The Nova and Camaro use all the same parts to swap over, and this is the single most common swap performed.

The only thing is you will have to wade through all of the gnashing of teeth and chest beating wails of the number matching museum curators who trailer their cars to shows and decry any one building "another SS clown" posts as well. It can become tiring to a car enthusiast who actually wants to drive a hot rod.


Big Dave
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You shouldn't have to change the whole heater box unless you are going from A/C to non A/C I don't know if you could get A/C with a BB in a Nova. If you have a non A/C heater box already you would need to get a BB heater core and the conversion plate to put on the heater box. The BB core exits in the middle off the heater box. Most of the Nova specialty places(J&W, Chevy 2 only etc.) have them.
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TDWZ28 said:
Front springs too.
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Hey Tony,

I'd leave the 6 cylinder springs in there...If you're going to drive it at all...much better for the weight tranfer :)

Here's my "old" '72 Nova which was converted from a 250ci inline 6 to a 402 big block in 1979-80. Don't worry...it's not around anymore :(

1971 402 ci, 8.5 to compression, Turbo 350 with Art Carr shift kit, Crane Fireball cam, Edelbrock Torker 2-0, 3310-2 Holley, 3:73 posi out of a totalled '69 Z/28, cheapo Blackjack headers and ran on unleaded gasoline.

The last I heard, the engine was in a Pro Street car...and the body was rusting away on 9th street in Anaheim, Ca.

These pictures were taken at the Street Machine Nationals West in Pomona in 1981. The time slip was from Orange County International Raceway.

Hey...have fun with the Nova. They are so much fun!






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1quik69 said:
You shouldn't have to change the whole heater box unless you are going from A/C to non A/C I don't know if you could get A/C with a BB in a Nova. If you have a non A/C heater box already you would need to get a BB heater core and the conversion plate to put on the heater box. The BB core exits in the middle off the heater box. Most of the Nova specialty places(J&W, Chevy 2 only etc.) have them.
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Thats right
, if you allready have A non A/C Nova you can just swap the heater core itself to the big block unit (I think around 50 bucks) and drill 2 holes where the heater hoses will go through your old heater box. You can buy the small plate with the 2 holes for the hoses to route through for about 13.00 bucks and use it as A template to drill the hoes. It's real easy and will save you about 50 bucks plus shipping. I believe NNN (National Nostalgic Nova) did an article on this in the magazine (Nova Times) A while back. The BB conversion will definately bring more bucks when you sell it but man, it'll be so much fun you won't want to sell it.....


Tommy
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