[hermie]

i am 64 yrs young and have my 8th cr it is a 72 nova 396 i need some advice on changeover from a sbc to a bc 4 spd i have heard so many things i must change any info will be apprciated

 

[Gloryhound]

Welcome to the site.

Not sure exactly what you are asking for but from the sounds of it your car is a sbc car currently and you want to make it a BBC car. Also it is a 4 speed transmission which adds a couple of parts to the overall swap.

A good staring list of parts that would be needed for the swap:
BBC frame towers
BBC exhaust
BBC flywheel
BBC Z-bar
BBC under the hood heater box (If it is an AC car I'm not sure if this box changes)
BBC heater core
BBC front coil springs (you can get away with the sbc ones, but I heard it makes the front a little soft.)
BBC tranny cross member (You can use the sbc one with slight modifications)
BBC radiator (or aftermarket aluminum)
BBC core support if origional BBC style radiator is used (or you can alter your existing one with a little cutting)
BBC fan shroud
BBC fan
BBC alternator, Power steering brackets(If equiped with PS), AC brackets (if equiped with AC)
Also I think the fuel lines need to be upgrade
And of course the BBC engine

I know their are a couple things I'm missing, but I'm sure someone will pipe in here to complete the list!

 

[Big Dave]

Need a one inch longer BBC Z-bar for clutch, and I was under the impression all the BBC's in a Nova were the solid lifter 375 horse 396 version; which means no A/C since GM never shipped A/C with a solid lifter car (except a few limited edition Corvettes).

Actually you will need to swap the P/S pump as well as the brackets as the BBC has the return hose (low pressure) in a different location to clear the heads.

If you have A/C currently you have the BBC radiator core support as it has a larger opening for the required four core Harrison radiator already. I have all the brackets you need to install an A/C with a BBC if you desire to do so as I got an extra set off of a '70 Chevelle (long water pump).

Your existing alternator bolts up from the small block but will not have enough umpph to keep the battery charged if you start your motor a lot because a BBC uses a high torque starter motor (has 5/8" longer armature winding than the SBC starter so the power lug is spaced out that much further forward of the solenoid with a brass piece making the connection) with the mounting bolts diagonally attached instead of across from each other so that it will not bolt up with the smaller diameter SBC flywheel (fewer number of teeth on starter ring).

The pedestal frame mounts raise and shift the crank center-line to the passenger side by one inch to clear the steering box. Because of this the holes in the BBC transmission cross member are shifted to the passenger side one inch also. There isn't a full set of cast iron exhaust manifolds around at a reasonable price, so I would only consider tube style headers for your exhaust unless you want the numbers matching thing. Distributor for a BBC has a different part number because of the different ignition curve but your SBC one can be modified with weights and springs to work.

BBC were only available in an SS car which means you need to have all of the SS equipment installed as well (multileaf rear springs, HD shock, 12 bolt rear end, HD battery, HD alternator, gauge package (installed in optional console), 15x7 inch Rally style wheels, disc brakes, F70-15 Polyglass Goodyear Raised White Letter tires, and SS trim package. This is of course unless you ordered it as a COPO plain wrapper car which shipped any way you wanted; he he! :thumbsup:

I will see if I can work up a list of all of the parts needed as this is a frequently asked question.

Big Dave

 

[TDWZ28]

Hermie...I just did a BB conversion on mine. If you have any specific questions, I will try to help you. Good luck with it. It's not too bad of a job.

 

[Big Dave]

I am not familiar with the 396 install after the initial offering (I almost bought one in '69 but didn't have enough established credit at the time and my dad refused to co-sign on "another hot rod"). :noway: But what I was looking at was the 375 horse solid lifter, which wasn't available with air (which in my dad's eyes made it a hot rod). Did they ever get around to installing the hydraulic cammed 325 horse and 350 horse round port headed version in third gens? Or were they all hot rods?

I have an 11 page word document I'm still working on so far with part numbers and information on the SBC to BBC conversion for first gen Camaro's and the third gen Nova. Still combing through documents and books for more info.


Big Dave

 

[Gloryhound]

They installed both RPO L34 and L78 engines in the 68-70 Novas. The L34 was a 350 HP version while the L78 was a 375 HP version. Both made 415 Ft lbs of torque. I don't know for sure, but I think the L34 was the Hydralic cammed while the L78 was solid lifter.

 

[Big Dave]

350 horse was equipped with hydraulic flat tappets along with the Rochester Q-Jet carb on a cast iron mid height manifold with oval port (254 cc intake ports) 2.06"/1.72" valves and 113 cc closed combustion chamber iron heads. It had 11.0:1 pop up domed cast pistons and a differed only in it's cam from the 325 horse engine (the 350 had 350° duration and the 325 had 322° duration).

I just couldn't remember when they were first installed. I new it would only be a matter of time as too many people think like my dad and wouldn't buy a car without A/C.


Big Dave