63redvette

I have an opportunity to purchase a reliably rebuilt BB396 with warranty from a reputable local company to replace my worn out SB400 in my 63 for half the cost of a new crate SB350 or SB400, with over 300hp. So, my question is...what must be modified in my engine compartment to accept the BB? I'm aware of the hood changes, no problem there...The original engine was a 327/360, but have never found it, and probably couldn't afford it if I did find it. I will search the forum for previous posts on this info, but welcome any good advice. Obviously I am not concerned about winning trophies, just trying to get the horses running again. Thanks.

1Cerberus4u

Top of my head

Radiator
motor mounts
bell housing
springs
Power Brake?
Power Steering?
exhaust

But then again, these cars are new to me too...

Easy Rhino

The notch in the front frame cross piece to allow room for the big block crank pulley didn't appear until the '65 model year, so there's that.
Where to place the battery.
The rear end was different, too (u joint caps and sway bar)

Nowhere Man

MikeM

My opinion as well but the OP asked what parts needed to be changed to get the BB engine in the car.

From memory doing this once in 1966, I believe it was only necessary to dent the front crossmember for the pulley and leave the hood unlatched to clear the air cleaner. The car ran warm in stop/go traffic, probably due to using the SB radiator so you'd need a bigger (new?) radiator along with a new radiator support to mount it. You'd need a new hood along with paint to get the hood shut. New alternator harness, hoses, fan clutch, exhaust pipes and engine shielding.

All this extra stuff will add up fast. From a practical point of view, I see the 400 SB a better fix for the issue than the 396 BB. .

Gavin65

Truth is a built small block will give you more than our asking for without changing out additional components as well as dimpling your frame, having said that there is nothing like the look of a big block in any engine compartment. If I had the deal on a 396 I would be dropping it into my 65.

LouieM

I don't see the value of losing 4 cubic inches and spending thousands on new parts to achieve ---- what? Gaining 200 pounds over the front wheels? Oh well, to each their own.

AZDoug

Yes, a front spring change should be done, also, for BB swap. A 400 SB will give you more power, esp if the heads are ported from stock, or aftermarket heads are used.
Doug

karkrafter

A big block in a 63 is just weird...and you will have to live with the weirdness now and even worse when you go to sell it.

Avispa

Bellhousing, clutch, clutch linkage are interchangeable between BB and SB. The starter will bolt up but it may not have enough torque for a BB. Exhaust will need manifolds and front exhaust pipes, the rear exhaust pipes will work if the SB pipes are 2 1/2 inch.

I'm inclined to agree with the others pushing a big inch SB. You can get a good 454 SB these days and not need to change anything.

karkrafter

I'm curious, what is wrong with the 400 you have now...super great street car mill with just a couple changes....

DZAUTO

Since you now have a SB400 in the car, then I would PRESUME that it has the large, 168 teeth flywheel. Thus, if so, then the ONLY bell housing which will fit with a 168 teeth flywheel is the 621 style bell housing. Also, IF that is what you have, then the same starter (with a cast iron nose and staggered bolt pattern) will also fit. Therefore, the clutch that is on the 400 flywheel, bell housing, starter and all clutch linkage will also fit the 396. You will need a NEUTRAL balance, 168 teeth, flywheel for the 396.

Now, with all that said, my choice would be to rebuild the SB400. I am a big time lover of SB400 and their derivatives (406, 417, 420, 427), all of which can be built in a bone stock GM 400 block. A 436 can also be built from a GM 400 block, but that is pushing the limits just WAAAAAAAAAAAY too much for my comfort zone. Of all the 400 derivatives, the 420 is my favorite (.030 bore/.100 stroke). With good flowing heads, flat top pistons, and a healthy hyd roller cam, this makes a killer SB400 that will live and is also 150lbs lighter than a BB.
I have a very healthy 406 in the 56 with a Bill Thomas modified FI and I've built to resemble (as close as possible) a 57 FI 283. It's just an evil car!

Additionally, if the decision is made to go to a BB, then my choice would be a 496 or 502. A good friend in Tulsa, OK has a 63 with a 502. Oh My God!!!!!!!!!!!

JohnZ

Consider this - you're planning to spend a LOT of money on an engine swap the car was never designed for and will need extensive (and expen$ive) modifications to accommodate, and when you're done you will have spent far more than you would for a 350 or 400 SB, and will have a Frankenstein car that will cause you much grief when it's time to sell it. Why bother?

Westlotorn

I believe the front springs will need an upgrade in addition to the other parts already mentioned.
Big blocks are cool and impressive when you lift the hood so I understand where the desire comes from.

I currently have a 400 SB in the shop being machined, have a nice set of heads for it and I know it will put out Horsepower and torque comparable to a stock big block.
A modified big block is another story but you can have 400 HP and 450 pounds of torque without much effort at all in your SB 400.
That is good enough for me.

karkrafter

What are you using for heads and cam?

Westlotorn

I want to keep compression under 10.5:1, I have a couple sets of heads already. AFR's with 210 runners and AFR's with 195 runners both 64cc and another set with 190 runners but with 72cc. I have also rebuilt my stock L79 heads. The cam is still up for discussion. I don't want a Hot Rod I'm leaning towards a good driver with lots of punch when needed similar to the stock big blocks. Still considering upgrading to the internal balanced crank and switching to 6" rods but that adds quite a bit to cost and I am not sure I will ever need to spin this past 5,800. It would be nice to use the L79 flywheel and balancer which can be done if internally balanced. This is a OEM block so I don't plan to go crazy with it.
Sorry we are going away from what is needed to switch to a 396 in a 63.

65air_coupe

Sounds like a nice build, similar to my 406. I did go with internal balanced cast crank but stock rod lengths for piston wear. You may have to go with those 72cc heads, I had to used 0.041" head gaskets to stay under 11:1 and I'm just barely there. My pistons have 7cc reliefs FWIW. The one big thing I did was modify the lifter valley to use OEM roller lifters/dog bones and spider. That kept my cam cost done nicely but was probably more than most want to get into too. I must say though that roller cam has a wonderful power curve.

cv67

Same here. Guys poo poo a 396 cause they are small..built right theres a real nice difference. Sorry bu\t no sb looks as cool as a bb plus the 396 has a discintive tone all its own .,Do it!

Maybe the guy just wants a BB and could care less about mystery buyer.

63redvette

okay, thanks to all for your inputs...I'm not worrying about selling the vette, its my 12th and last hotrod for me since 1978...I'm aware of the mod costs, but am on a limited military retirement and disability income after 24 harsh years in spec ops aviation pilot and cannot do all the work myself due to injuries in 2014, so if it aint affordable, it aint going in the vette...objective is to get the damn thing running within budget of $5k...I'm going to see what the guy will charge for a worst case rebuild of the SB400, but it may not be an option, I dont like rebuilding a block three times, twos my limit in the past...online crate SB400s from pan to carb are $5-7k...so, I have few options and dont want to drop to a SB350, its just not the same although it is better than sitting in the driveway staring at the car...Thanks again amigos...I will let you know what the wheel of misfortune has in store for me when I decide this week.

ghostrider20