604

Any one who has done this? Curious how hard it would be. I was going to start building a 400 for my vet, but big blocks have gotten so cheep around hear I am thinking why not go bigger! That is if it is not to hard to do. Thanks for any input!

milo30

Doing it myself. You will need new radiator, springs, brackets and pulleys for vette bb, I think motor mounts are the same, maybe larger exhaust but I am already running 3". Probably more that I am not thinking of right now. More expensive than a sb replacement but worth it to me.

604

Thanks!
I was figuring on those things. But I am woried about the heater box. Just not shure if a big block will clear or not.

Vette5.5

Think I'd stay with your plan on a nice sb 400 build, as it will drop right in. Maybe a bigger radiator, but really not much else. Beside's saving the extra bb 110lbs hanging over the front axle, you can probably leave the hood alone too.

604

Not to woried about the extra weight. I have been playing with my friends 69 427 and it handles just fine. And I LOVE the brute torque of the big block in his vet.

MrForce

Look at RebelRob's build and you won't be able to find reasons not to do it...

604

Were would I find that?
Thanks!

MrForce

Here you go

http://forums.corvetteforum.com/c3-t...-454-pics.html

milo30

Same here. Yes I can get a 350 or 383 crate cheaper and yes I can buy a 454 crate. There is a reason that I love the old BB vettes. There is also some satisfaction in knowing that you did something yourself. That's why I am swapping the sb for a bb. I'm not worried about the extra costs or weights that will be associated with the swap.

I'm just in the beginning stage of this and am moving really slow trying to get all my ducks in a row but it will have the bb in it unless I find a problem with the block that I picked up for this.

I hope to have my stuff to the machine shop this week if all goes well and I'll start posting pics and info on here. If I run into anything major then I'll let you know.

markdtn

You will want to investigate all the costs before you do this. You will need front springs which are not expensive, but not trivial to install (and shocks while you have them off and maybe ball joints) If you keep the a/c you will have to convert to a long compressor or aftermarket and a new freon manifold/hose (and a dryer and orfice tube while it is apart). You will have to have all BB pulleys and brackets and they are not cheap (and belts and a water pump). You will have to have a bigger radiator (and electric fan conversion with alternator or new shroud and fan and/or fan clutch). You will have to have a new hood (and paint) or lowrise intake (and carb and air cleaner). You will have to have headers or Corvette-only BB exhaust manifolds (and some exhaust work). By the time you spend all that you could come close to a LSx conversion and have it all-mileage, startability, power. Just something to think about.

604

Keep me posted. I found this on the net. Shows my vet (not realy) same color and same year with a 502 in it. Looks like it clears the heater box just fine.

http://www.ls1tech.com/forums/vehicl...ock-502-a.html

Thanks,
Kevin

markdtn

Yes, the heater box is the least of the problems.

604

To each there own. I would rather have a big block that a fuel injected engine. I drive all of maybe 2,000mi a year. This is a play toy not a daily driver.

I already have a 3 row radiator, and do not need an electric fan. The 69 427 I work on cools just fin with the factory fan. I have no need for a taller hood, though I may put on a L88 hood any way. If it fits under a low 69 hood that it should fit under a tall 78 hood no problem. I already have a low rise inake. I priced the brackets and they were not that bad. Already removed the AC so no problem there. I want new springs any way. They are 32 years old and need replaced. And it looks like rebuilding the engine will only be about $200 to $300 more than building the small block I was going to build. From all I have found on the net it looks like not that big of deal to do.

As for stability,
I have put more miles on the 427 69 than on my L48 78 and I can not tell a notable deference. I am sure if I did road racing you would be able to tell. But for what I do there is no deference.

milo30

Same here. An LS swap was an option for me but the idea of having a bb again really settled it all. It's a hobby and will cost whatever it costs to finish the job. Alot of the things that need to be changed are things that I either needed to change like springs, radiators, etc. Most of the others like the hood I already wanted to change. Paint is already in the budget even without an engine swap.

Bite the bullet and do it.

Shark Racer

Big blocks are the best way to go for absolute power... but I like wrenching on my car and it's already a pain in the *** to get at certain things with the small block in there.

My truck is a big block though, and whenever I get the urge to build the motor, an extra 200+ hp is heads and cam away..

TheSkunkWorks

Not a big job at all, as long as you use the proper bits for a C3 BB installation and recalibrate your budget conceptions. I've had nothing but BB's in my '78 for nearly 30 years, tho they've all been 427's. In the midst of doing another one now (if only my income stream would improve). Go with aluminum heads if at all possible and save ~75#, which in combo with alum intake and water pump puts engine weight at less than 100# over an L82. IMHO, changing plugs on a BB is easier than on a SB.





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markdtn

If you want a BB, get a BB. I was just pointing out an alternative. A BB swap in a C3 is a mostly bolt in swap with no real mods to the car-just a lot of early BB parts to buy. As far as a few of the things you said, I am skeptical. I have never seen a BB fit a flat hood 68-72. There is just no room. Yes, the later hoods have more height. I have never seen a C3 BB cool effectively with a 3-row copper/brass radiator-Aluminum yes. There is just a lot of heat to reject. I had a stone stock 77 Bonneville Pontiac 350 with a pretty new 3 row radiator. Motor died so I went to a stock 455. I had to go to a 4-row as it would overheat in summer even with a fixed fan. Now change to a "built" engine with the C3 canted nose and I just don't see it working with a 3-row and stock fan. Hope it works as well as you plan.

chevymans 77

heater box and brake booster are no issues if you stay with the short valve covers.

stay in the 450 HP range and the cooling system will more than likely be no issue either.

the pulleys are the only thing you will need to work on and find

headers are cheap and can be found just about anywhere

with a low intake the hood wont be an issue

put it in there and have some fun with it

these cars came with a BB's up untile 74, it will fit


Neal

bashcraft

The stock copper/brass small block radiator and stock clutch fan in my '69 has no problem at all cooling my zz502.

Just because you haven't seen it, doesn't mean it's not true.

Rebelrob

I just did all of this. New hood, BB, new radiator, etc.
Depending on where you live, will probably determine if you can get away with your stock copper radiator. If you live in South, like here in Texas, where we have Hell on Earth summers. Just about every day this last August we had 100* + temps, then it cooled off to 98 and 99. I did not take any chances, I tripled and then some my HP, so I got the Dewitt set up and my engine is running nice and cool, granted the outdoor temps are cooler, but I do not think I have broken 180 *. The fall and winter are the best times of the year here for cruising. Nice and cool.
Good luck and have some fun with it.
You will not find a better forum, and also a great group of members to help you thru it.