I have a 1970 Camaro that previously had a small block in it. I bought it as a rolling chasis and am leaning torward a big block (probably 454 or 502). Since these cars came with big blocks, I figure stronger springs and different motor mounts would be about all it would take, if I stay with a TH350. The frame is tied to avoid twisting the car in half.....

Anyone have any experience with this? Tips or advice welcome.

 

Pretty easy swap, and you wont need a lot of parts to complete it. The turbo 350 is actually a better choice behind the big block because of it's lower spun weight, so it loses less H.P., but you need to build it properly! It will need the full Corvette clutch pack, and also a high quality shift kit. I put a Transgo Competition kit, and the Corvette clutch pack behind my 450 hp. 427 CI swap, and it's been there for over 25 years without touching the tranny!
The motor mounts depend on what you want to do. If it's going to be a hotter engine, then go with poly mounts, or solid mounts for race setups. All V8 mounts are the same for this generation, so just buy the performance level you want and they will work.
I left my smallblock springs alone, and still have them in, but I liked the stance, so didn't want taller BB springs. Be sure to get the heavier sway bars up front, and in the rear if you plan to do much cornering. I upsized the front, and later the rear also, as that's a lot of weight in the curves. My car was an SS, so I had multileaf rear springs, but if you've got single leaf rear springs, better upgrade, or wheel hop will be rediculous!
Traction! I started out with some leaf spring mount traction bars that worked OK, but eventually went with Lakewood ladder bar kit. If you're pushing over 400 HP, you'll want some really good bars, and tires! Mine will easily light up my 13" Mickey Thompsons if I launch too hard without lowering tire pressure. That's a light rear end, and even more so with the extra front end weight.
Also spring for some good gas shocks. The difference in driving will be worth it. I upgraded my rear brakes with drums from a late 1960's Impala. A disc brake system would be nice, but expensive, so the extra large Impala drums and backing plates give super braking at a very cheap price.
Be sure to drop in a set of headers when you do the swap! Headers make spark plug changes a snap on the BB, and much easier to install during the engine swap. I put a set of Doug's headers on mine when I did the swap, and I can change the starter, plugs, oil filter, etc. with no header interference!
Make sure you get the power steering and alternator mounts from a BB car too! Your smallblock mounts wont work, and it's cheaper to find a donor car or truck with a BB and rob them than buy new!
Hope this helps!-Vall

 

would he need traction bars and subframe connectors or just one of them?

 

Both.

 

Thank you for the post. Im glad to see that this wont be a problem. I am looking at over 500 hp maybe as high as 650. I am starting with a motor (probably a 496) and then building a trans that can handle it. The car alread has a Ford 9" - frame connectors - and traction bars. I know wheel hop will be an issue - never thought about the sway bars, so thanks for that tip. I did see the ladder bar set up you mentioned in a restoration catelog and it was reasoanbly priced. Chances are I will need it. Gas shocks are already installed. The car has vented disk brakes (upgrade) up front - looks stock in the rear.

The front suspension is all brand new - but unfortunately it has a 2" lowering spring package up front. Chances are with the extra weight of the BBC, I will need to upgrade. We will see.

Thanks again.

 

Sub frame connectors are a must for anything over 400 hp, unless you want the body to tweak out of shape. I ran mine for years without them, and had to go back and realign all my front end sheetmetal before repainting. Then I added connectors to keep it all together.
Subframe connectors do little to stop wheel hop or traction issues. They're strictly to keep everything together.

 

i know that traction bars help with wheel hop and traction but do they also help with traction when its wet out? since they supply more force downwards

 

No, there's not much that will help with traction when it's wet. If your car can spin the tires when it's dry, it will just spin them more when it's wet. Nothing short of good rain tires can help in wet weather traction.