Technical BBC in a 51 Chevy Coupe, who has done it

Engine set back/balance, over the rail header?? So are ya drag racing?
Restore? We don’t do that.
Too nice to cut? That doesn’t exist. But nothing wrong with a well executed thought out slice.

Stab the engine in, build mounts and move whatever is in the way.

but when I had to figure out engine placement/weight ratios we used scales to weigh the car. Looked up engine and trans weights and made our best guess. Weighing also helped figure out spring rates.
Then cut the firewall and trans tunnel out and build new after the engine was mounted. Can’t do this worrying about cutting a car. Installing a big block, auto and rear and thinking about originality don’t mix.
Remember, every mod can lead to 10 more. Set the engine back then what about pedal placement, building a firewall, trans tunnel mods, wiper mechanism, frame x-member mods….

honestly for me the, I’d cruise the crap out of it while since it’s still running

 

If you look at your firewall you will see 2 body stiffiners one on each side of the 6 cylinder. You will need to cut the bottom of them to make room against the firewall. Test fit the engine with them in. Mark them where they need to be cut to help clear the new engine. Leave at least 1/2” of them where you cut to weld back up for strength. Good luck and have fun with your fast ride!

 

Stock manifolds most likely won't work. Hard to clear the steering or oil filter and frame.
I have only done sbc in those frames.
I would make headers to fit once everything was in place. Expect to cut inner fenders.

 

I haven't raced in a number of years. My last go fast car was OT and I bought it off the showroom floor and then I worked on it.from there. Wicked fast on the top end, but still was only low 11s in the quarter. Been remarried for 12 years now and that car is long gone as well as a long dry spell in playing with toys. But, it is time to have fun again. She will either enjoy my toys or not, but I want to live again. And yes, I corner balance most of my toys. Going fast is fun, but going fast and being able to turn at the same time is where it is at in my opinion. I want the car to be capable, yet not overly capable or I'm afraid I would give in to temptation. In other words, I don't want to build it just to race and wind up back in my misspent past. I'm too old for that foolishness. But, I do want it to be respectable. Maybe an occasional trip down the quarter, but no street racing or back road corner carving while someone tries to pass me. But you are right, I can't worry about to cut or not. Maybe in a couple of years I'll be looking to unleash a little more from the car. My goal is to have the drivetrain and power in and driving for Good Guys in Des Moines this year and hopefully the interior up to snuff.

That video is great. Loved that they played with it back when, left it, pulled it back out and reworked it. And the car looks pretty nice. I like the build it, test it, perfect it, then finally do the body work and paint it method.

 

I think you'll find the weight increase of the BBC engine over the straight six, plus the V8 being shorter so weight is already back a little more vs. the six, wont be an issue that requires any firewall setback.
I haven't done any BBC V8 swaps in the old Chevys, but I did own a '53 Chevy with a big old 371 Olds engine and Hydramatic, and the firewall was unchanged. And that car used stock front suspension with just heavier coil springs to handle the extra weight.
I've done a lot of SBC swaps into pre-War and pos-War Chevys and they fit as good as later 50's Chevys with stock V8 engines. Height is never an issue with any of the 30's-50's Chevy cars and a BBC engine, and likely you wont run into any clearance issues to length of width unless you do try to move it too far back. Your stock firewall inset for the six will give your BBC distributor plenty of clearance and still allow room up front for a mechanical fan if you choose that route. The firewall mounted master wont be an issue either, unless you choose to add a power booster. The booster may need to be one of the smaller aftermarket units to ensure clearance for valve cover on that side. A manual brake master wont be any issue.

 

When I built my Nova stock car in late '82 I went BBC and it was definitely fast. I switched to a SBC in mid season '84 and it was like another car. With less weight up front it cornered much betterer. With your car, the right springs and a fat sway bar will be a big help.