Chevy Nova Forum banner

1 - 13 of 13 Posts

·
Premium Member
Joined
·
2,833 Posts
Discussion Starter #1
Hello all, I was wondering if I can get suggestions as to what is required to get a BBC in a 69 Nova that originally came with a 6 cyl. I don't want to start buying the wrong parts. I would like to know what is required to get the stock hood to work without going cowl hood.

I believe I would need BBC frame mounts, offset th400 crossmember for the TH400 I plan to run.

What is the lowest profile aluminum dual plane intake that would work with a holley 4 barrel and stock hood?
Anything else?

Any advice would be great. Thank you, SS
 

·
Registered
Joined
·
1,372 Posts
So, this is not difficult at all since GM installed a 396 in a '69 Nova making all of the parts readily available.

Here's a list to get started, others can add:

- Big block frame mounts, also called engine stands, they mount to the frame cradle and accept the engine mounts. These are diff than SB's because they shift the engine 1/2" to the passenger's side in order to clear the steering box. Since you are running an a/t, we don't need the BB specific clutch stuff or trans crossmember, the auto x-member for a TH400 is the same for BB / SB to my knowledge and accommodates the 1/2" shift. The BB engine stands do not shift the engine forward like some might claim, the size of the engine block relative to the engine mounts does that - the engine stands will bolt directly into where your 6 cyl mounts are now, you will not need to drill any holes (but I hope you have small hands to reach the attaching nuts!)

- Heater core and heater core cover. The 1/2" shift towards the passenger's side essentially makes attaching the heater hoses to the SB location nearly impossible. So, you will need a BB core and cover along with the core attaching clips. Be careful what you buy, the most common BB heater core does not fit well (at all really...) and is actually specific for a '67 Camaro! :mad: Ask me how I know... The best BB heater core to buy for a Nova is from Heartbeat City in MI. I can attach a pic if you'd like so you can see the differences. Use the AIM to assemble the clips, etc

- Radiator support, radiator, shroud, etc... The BB rad support has a larger opening than the SB / 6 cyl versions, and it has some special weld nuts and holes to attach the radiator to it. The SB version can be opened up to the BB size by following the natural rib on the driver's side, or use a SB / 6 cyl with a/c core support which also has the larger opening, but you'll have to close up the ac specific holes in the support. The fan shroud and hold down is different, but all available in repro - and they fit fine. The radiator is also available in repro, I'd suggest Quanta or US Radiator (they might be the same...)

- Wiring harness. I think the SB version will work, but you'll need to investigate whether the 6 cyl harness will suffice and how much altering you're willing to live with

- Shifter. Assuming your 6 cyl came with a column shift PG and related neutral safety stuff, you'll have to convert to a 3 speed setup - prob easier to convert to floor shift unless you are doing a concourse setup because a floor shift a/t requires a console which requires buckets which requires deluxe interior....the costs snowball if you choose an a/t on the floor in a stock configuration.

- What else???
 

·
Registered
Joined
·
712 Posts
Just want to thank Yenko for all that knowledge! Contributors like this is what makes SNS so awesome. Ok back to the thread...

What else??

Sent from my SM-G975U using Tapatalk
 

·
Registered
Joined
·
1,492 Posts
You'll likely need larger fuel lines, as well.

(...)Since you are running an a/t, we don't need the BB specific clutch stuff or trans crossmember, the auto x-member for a TH400 is the same for BB / SB to my knowledge and accommodates the 1/2" shift. (...)
Incorrect.
The standard Big Block / TH400 cross member is required. (Or modify what's in the car.)

Other cross members, and the SBC/TH400 cross member, don't offset the transmission mount correctly for a big block or don't match the TH400 length.
 

·
Registered
Joined
·
198 Posts
I just finished a big block conversion (350 to 454) in my 72. There are minor differences to your 69 but they are for the most part identical. When it comes to hood clearance mine fits under the standard hood.

The big block does sit forward and to the passenger side as compared to the small block with the correct big block frame mounts. Side by side comparison of the small block and big block frame mounts shows an obvious shift forward and a more subtle shift to the passenger side as a result of the taller mount on the drivers side and shorter mount on the passenger side.

These are the parts I used as recommended by others on the site. Worked without any issues.
frame stands K701
motor mounts T82283
heater box cover AL303
heater core H2239

The rad is where your 69 may be different. The rad in mine mounts in rubber bushings top and bottom, sitting in rad cradle position at the bottom and held in place by the upper bracket. I replaced my original rad with an OER reproduction (CRD1013S) which mounted in a wider position on the cradle and I found an upper bracket and shroud from a 73 Ventura to keep the original look. I cut the rad cradle at the pressed line to widen the hole for the larger rad.

These are the parts I used as recommended by others on the site. Worked without any issues.
frame stands K701
motor mounts T82283
heater box cover AL303
heater core H2239

The rad is where your 69 may be different. The rad in mine mounts in rubber bushings top and bottom, sitting in rad cradle position at the bottom and held in place by the upper bracket. I replaced my original rad with an OER reproduction (CRD1013S) which mounted in a wider position on the cradle and I found an upper bracket and shroud from a 73 Ventura to keep the original look. I cut the rad cradle at the moulded line to widen the hole for the larger rad.

Hedman headers (68198) fit great with one healthy dent to clear the power steering pump. I had to use this set due to the larger port heads.

I used the intake manifold that comes on the gm performance 502 and with a Holley 750 and drop base air cleaner it just clears the hood.

If I can help with anything more let me know.
 

·
Registered
Joined
·
198 Posts
Took me a while to put that previous post together. You will read some paragraphs twice. Editing seemed to make it worse every time - gave up trying to fix it!
 

·
Premium Member
Joined
·
2,833 Posts
Discussion Starter #9
Wow!!! Thank you guys for all the help. I am going to start the collection of parts. BTW, I am going heater delete and Manual Steering box. As well I will try to tackle keeping the column shift if possible, if not I will go floor shift.

Awesome help all!!
 

·
Registered
Joined
·
198 Posts
Mine was manual steering and even with the small block it was a brute to maneuver in tight spaces. I upgraded to power steering (CPP kit) with the big block going in and I’m really happy with it. Effortless steering, just had to dent my way around the larger steering box. There shouldn’t be any issues maintaining your column shift. If you need anything for the conversion “Shiftworks” is your go-to store for that.
 

·
Premium Member
Joined
·
2,102 Posts
You dont need to change the radiator support or go to the big block radiator mounting unless you want it to look correct. If you just want a big block in there, small block stuff works just fine. I use a Summit aluminum radiator in the stock small block mounts, small block top plate, and a small block fan shround with just a little trimming. Keeps my 427 nice and cool.

But one area with a big block, if you are using the 69 and newer water pump and pulleys, you cannot run a clutch fan. If a mechanical fan it will bolt right to the water pump. If you decide to run a 68 style short water pump and accessory mounts, you can run a clutch fan. Room is tight for electric fans, but that is an option as well.

As for intakes, the factory aluminum intake is a pretty tall piece. You should be able to fit a Performer RPM with a Holley, and a drop base air cleaner under the stock hood. If you are building a big big block, with rectangle port heads, Brodix makes a nice dual plane intake with big runners that sits a little lower. But its advertised as a 3500-6800 rpm intake.
 

·
Premium Member
Joined
·
31,194 Posts
1 - 13 of 13 Posts
Top