HOW MANY 1975-82 BBC swaps do we have?

grumpyvette

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Staff member
HOW MANY 1975-82 BBC swaps do we have?

This was a popular swap when I was younger, so Id imagine theres still a few out there?

bbctripower.jpg

factory big block three deuce intake

as many of you guys know the last factory BBC vettes were the 1974s but because the basic car didn,t change a great deal durring the C3 life it was and is still possiable (with some research and skills and work) to retro-fit the later 1975-82 c3 with a big block engine, the mods necessary vary with the year, but all can be adapted after modification.

I helped a buddy stick a 496 BBC stroker engine (.060 overbore/4.25" stroker crank) /turbo 400 trans combo in a 1976 vette, it was a clean looking almost factory install, when we were done. the only major changes were a differant hood for clearance, bigger aftermarket brakes and heavier springs and sway bars, and HD shocks, everything else was doable with mods to the stock parts
we replaced the rear suspension with a 1970 bbc rear suspension,only after its stock rear self destructed but that surprisingly took a few years
KingC6
posted this great photo
IMGP1222.jpg


btw if your looking for very in-expensive corvette bbc headers these work

http://store.summitracing.com/partdetai ... toview=sku

http://tech.corvettecentral.com/2015/11/67-69-tri-power-carburetor-tuningtroubleshooting/
 
Last edited by a moderator:
MR.KISS POSTED THIS

CIMG0470.JPG


I just recently installed a 572 into my 79 vette and believe it or not it was pretty simple with no major problems.

First off i had to make some room under the hood - i installed a hydroboost brake booster to give me room for the tall valve covers. I should note that the car had no Air Conditioning.

I used stock small block motor mounts and bolted the motor in, the 572 flywheel uses a 4l80 converter bolt pattern so this had to be replaced with one that has the smaller pattern for 700R4s. The left valve cover slightly touched the firewall, so i installed a 1/8 shim under the left motor mount to pull the valve cover out of the firewall. Also the 572 oil pan touched the steering ram on a hard left turn and this shim game me just enough clearance for that. The left valve cover can now be removed without any difficulty. The wiring harnes was anouther problem, it came out of the firewall and right into the valve cover. To solve this i relocated the wiring harness firewall hole to the right about 2 inches and installed a body pug in the old hole.

i used a march serpentine belt drive kit with a remote PS pump and installed a alternator from a 90's gm truck - this is nessary to get room for the hood hinge when the hood closes. The belt is about 60". I used electric fans, so rad shroud and fan is not an issue.

For Exhaust i used a set of Hooker SuperComp Sidepipes. The right side bolted right in without any trouble.

The left side was more work. The number 2 tube neede do be slightly dented more, to clear the steering box. There needed to be some clearance made for the tubes as they pass the frame rails and exit the side of the car, i think this problem was created because of the shim under the left motor mount and maybe could have been avoided if a differnt oil pan (clearance for the steering ram) and some firewall mods where done (clearance for the valve cover). So i opted to dent the tubes of the header.

I used a l88 - lt1 air cleaner with a 3 inch element. The hood i originally had was a 79 hood with a l88 scoop installed on it, i measured 4.25 inches from the scoop to the fender drip rail. When this hood was closed it just touched the air cleaner. To solve this i installed a l88 hood with a 6" scoop. this allows me to run a 4" element air filter.

I also installed Big Block coil spings in the front and a 6-link in the rear for suspenstion work.

On thing to note is the 572 oil pan is very low so if you are using tires smaller that the original 27" tall - be very careful about what you drive over.

I have to say this car is way to much fun to drive.

CIMG0454.JPG

CIMG0503.JPG

when i bought the car 20 years ago the only way to get it to lay rubber was to lock up the brakes ... thats what inspired the big block transplant ... originally i went from a l48 to a aluminum headed 427 with a tri-power and a 700r4 ... then it would lay rubber.

5 or 6 years later the 427 cam unglued at 6500 and there were not to many salvageable parts .... it sat apart for 8 years then i decided to put in the 620HP 572 and now it reallly leaves black marks ... time for some viper rubber ... i think that is my next project .... the 28X12 mickey thompson sportsman sr just don't cut it .... way to greasy

When you roll out on the road from a stop then stab the throtle the engine instally hits the studder box at 6000 rpm, so you take the next gear and the engine stays on the studder box and the speedo needle goes crazy ... so take the next gear and same thing still on studder box --- never lost 1 rpm but the speedo went crazy again and buy this time you can not see anything behind you at all and that funny smell of something burning is getting much stronger .... i never had the guts to take forth gear -- i was shy.

I could not imagine what the 720 hp version would be like, but let me tell you this motor is seriously underrated at 620 HP.

I should also mention, i did not use the demon carb, i used a 950 holley ultra hp carb and there are no mufflers in the pipes i love the sound at 6000 rpm with straight pipes -- just don't drive it at night or giver shit around town and i have not had any trouble yet. One day i will make my own version of those spiral mufflers .... no way am i gonna pay that guy $350 for his, when i can make the same thing with auger flighting and a mig. I also used a msd electronic advance distrutor and a jacobs pro 10 ignition system and taylor 10.4 mm wires.

Ok here is some answers for you guys:

yes it is a tall deck block.

I spent about $20,000 canadian. That includes, crate motor, new carb, new distributor, new wires with boot protectors, electric fuel pump, aluminum rad that i destroyed :lookinup: , headers and sidepipes, serpentine belt kit, alternator, hi torque mini starter, remote style power steering pump, power steering pump reservor, hydroboost and lines, l88 air cleaner with lid.

AS for the old hood that is a touchy subject - a friend of mine that manages a body shop said he colud raise the scoop an inch for me so i said ok - after 2 months he sends me some pics of the raised scoop - it was the worst thing you could possibly imagine it looked like someone glued a winnabego on the old scoop. So i went shopping and let me tell you 6' l88 vette hoods are not easy to find and of all things Vanacorvette was hit buy a huricane at this time - i am asuming that is why they never answered their phones for the 3 weeks i was trying to call them. I found a guy in toronto canada that does balwin motion replica kits and talked to him and he said a 6' l88 vette hood was not a problem so i ordered it - well let me tell you about that. When the hood finally showed up the fit was incredibly terrible i should have sent it back, but he had my money already so i figured i would lick my wounds and hope that i can find someone to make it fit properly when i get the car painted. I am sure it is gonna be 20 hrs to make that thing look respectable, and now the guy will not answer when i call. NEVER buy from a place called showcars in Toronto Canada, prices are great but product sucks and service is worse, Hey Strider are you in that part of the country? If you are, Could you please!! ride your horse over to this guys shop and park him on the door step for a couple hours then tell him whats left on the step its a tip from terry. Sorry guys i'm venting.
http://www.duntovmotors.com/vintage-rac ... s-body.php

As for mods to my car well i am using a incredibly well built 700r4 it spent alot of time getting beat up buy a 427 at the drag strip and i have never had to fix it once other than a converter seal - if i ever get the car to hook up i suspect i will have trans problems.

Rear end is a stock 4.10 gear with a DRAGVETTE 6-Link rear suspension with drive shaft loops - yes loops one on each half shaft and also and optional one on the drive shaft this makes the stock ifs suspention NHRA legal to 10.50's. I can not recomend more than to shop with this guy, he is so good to deal with and the product is A++ I ordered the kit for his daul mount spring, it is such a perfesionally built item looks like GM made it that way. I use his dual mount spring set up on a single mount spring just because it looks more GM Built. I was quite worried about axle problems but after talking to alot of road race guys that said the only things they really have broke are U-Joints. I decided to only install brute strength u-joints all around and u-joint guirdles from moroso on the diff side of the axles. One note on the u-joint guirdle if you use them - you must fit them to the yokes or else the cups do not sit snug. The instructions never said anything about fitting the cups to the yoke but i happened to check this on install and found this problem, an easily fix with a file and some patients. I also made a Traction bar that is similar to the one that Tom's diffs sells - he just wanted to much money for one of his and he really wasn't that nice to me on the phone so i figured i would save my money and do the work myself, this traction bar is not rocket science. Just a note - this traction bar uses the same idea that balwin motion used on their vettes. i also installed a HD diff cover and a 420# composite rear spring and bilstien shock all around. These rear end mods improved traction 100% from the factory set up and the 572, but as the picture shows i still have alot of work to do to get this thing to hook up.

I used the new mickey thompson sportsman sr street tires and i can not say i am to happy with them 28x12 on the back which only measure 10 inches wide that get real greasy once there is heat in them. I used to use dunlop 295/50/15s on the street and i think these are better than the mickey thompsons honestly.

The interior of the car is pretty much stock i did put a power seat out of a 81 vette which turned out to be alot of work - the floor pan on the 81-82's with power seats are different and i had to lower mine 1.75 inches so the seat would fit right. I used a center cluster out of a 81 to get the engine temp guage. Also thanks to ecklers i have i nice new interior, The car originally had red leather that i did not like so i changed to blue which is much nicer but let me tell you painting red panels blue is a complete waste of time. They always get chiped and the red shows through - so if anyone is scrapping a 79-82 vet with blue interior please PM me i need some parts. Also if anyone has a non ac temp control let me know i need a new face plate or at least one that is not broken that i can restore.

Exterior mods are 80 style bumpers front and rear installed. The hardest part of this was taking the 79 bumpers apart - wow so many pieces and bolts but the swap was ok. Just a note: if you are doing this swap and not good at fiberglass work the front fenders will look a little funny were the new bumper bolts up. Spend the money and buy the fender adapter panels that vanacorvette sells - i will be buying them when its time to paint the car - i am not a body work kind of person, so this will be the easiest option.
 
MR KISS SAID
For Exhaust i used a set of Hooker SuperComp Sidepipes. The right side bolted right in without any trouble.

The left side was more work. The number 2 tube needed to be slightly dented more, to clear the steering box. There needed to be some clearance made for the tubes as they pass the frame rails and exit the side of the car, i think this problem was created because of the shim under the left motor mount and maybe could have been avoided if a different oil pan (clearance for the steering ram) and some firewall mods where done (clearance for the valve cover). So i opted to dent the tubes of the header.

The reason I was asking about the deck height was that I was surprised that Hooker side-mount headers would fit with the "non-stock" location of the exhaust ports. Is there a special set for this application?

My friend recently installed a 540 in his '69 and traction control is definitely an issue. That car of yours must be some crazy ride. I may have missed this, are the 4.10s still in the car? My buddy is using a 3.36 rear, 28" tall tires and swapped to an M21 for the numerically low 1st gear to try to calm things down in 1st and 2nd.

More and more, a 427 is turning into a pee-wee sized engine
The Headers are the Regular big block side pipe super comps from Hooker. Its a tight fit and like is said there was some clearance issues but i never had to chop the header apart. I must mention to get the front 2 spark plugs out you all but have to remove the header. Also the 572 heads have the exhaust port raised over stock heads exhaust port - this is what creates the spark plug problem.

If you choose to modify the firewall a little for valve cover clearance and dent the oil pan or remove the power steering assit ram. Then you do not need to shim the motor mount and i suspect the headers will need no modification accept a little clearance around the steering gear.

The guys at the tire store do love me ... haha. I just ordered some new tires which is going to be the next major conversion to the car. I am going to install 345/30r19's in the rear. I always follow the theory that bigger is better. Thanks to all the guys that post information in this forum i am pretty sure i can get them to fit under the fenders mostly, have cut off wheels and a welder and will get to WORK making some room. I kinda like the 70's look where the tire sticks out of the wheel well a little. The wheels are going to be custom made and will be a 19 inch replica of the factory aluminum, i have gotten some quotes on prices and it will be reasonable for a one of wheel. I am going to install a 255/40r 19 on the front.

Has anyone on this forum ever installed a 10 wide wheel on the front? what kind of success have you had and what back spacing did you use?

Also i am planning to do a power steering swap. I really like the jeep steering box mod but i am pretty sure i will have header clearance problems with the tall deck and the hooker side pipes. Has anyone done this swap using the chevelle pit-man arm, what was your success? I am thinking about cutting the frame out to make more room for the box to solve the header problem, but if it gets moved to much then one will run into the steering arm will not be perpendicular to the drag link when straight ahead. Any advice would be greatly appreciated?

I may go to the 92 grand am rack and pinion which also provides a bump steer problem solution i just don't want to make things to low on the car, The oil pan on the 572 is very low and when i had 265/50r 15's on the front the front spoiler was only 2 inches off the ground and the pan was not much higher than that. So i put 28 inch tires on and the hieght is right but the car doesn't look right with the really tall tire so i am going back to a stock height of 27.

For anyone doing a tall deck transplant just be aware that if your car has air conditioning i am pretty sure you will run into problems with fitment on the right side in the ac box area - especially if you use the tall style valve covers, be prepared to do some glass work on the box to make some clearance. My car originally had AC but i changed it a regular heater system which was pretty simple - just had to glass up the firewall. That was over 12 years ago when the heater control panel for a non-ac car was available from gm, but now a days that piece is impossible to find. So doing some mods to he heater box is much more practical. With the tall deck block, none of the factory big block brackets work so you have to go to a aftermarket serpentine system so why not get one that allows for the AC compressor. Your transplant will be a breeze.

http://www.fidnet.com/~harleyms/serpentine%20page.htm
 
hello,grumpyvette
I am getting ready to drop a ZZ502 in my 75 with TH400 (rebuilt) and ac. (street car with good manners) these are current issues:
radiator (I live in HOT south florida)



  1. [*]exhaust (thinking side pipes)

    on a 1975 ID sure select the , hooker side exhaust over running a restrictive under the car and thru the frame exhaust, btw look thru the links
    http://www.summitracing.com/parts/HOK-2233HKR/

    http://www.summitracing.com/parts/HOK-50735-1HKR/

    in fact thats what I ran on my 496bbc in my 1968 vette, but use the spiral baffles, not the factory insert mufflers

    viewtopic.php?f=80&t=793&p=1150&hilit=inserts+exhaust#p1150


    heres a 1975 with side pipes installed (SBC IN THIS CASE)
    file.php




    [*]torque converter

    Id select a decent 3000 stall converter from a major manufacturer, as it gives you a great deal of flexibility in cam selection and helps performance
    viewtopic.php?f=71&t=2400

    viewtopic.php?f=71&t=1715

    [*]pulleys (thinking 1991-94 serpentine system with available conversion brackets)

    that should work but theres other options also
    viewtopic.php?f=38&t=1113&p=2340&hilit=+serpentine#p2340


    links below should help

    http://www.alangrovecomponents.com/Powe ... .htm#small

    viewtopic.php?f=38&t=200

    http://www.millerspeed.com/

    viewtopic.php?f=38&t=200

    [*]valve covers (heard I might need a "notched" version because of the ac

    this is usually true, plus the booster may cause clearance issues on the other side in some cases

    [*]fuel pump/lines


    these stock line will work as is, but really should be upgraded, if you intend to get max performance
    viewtopic.php?f=55&t=211&p=6904&hilit=line+size#p6904

    [*]can I use the oil pan that came with it (stock springs)
    since I don,t know which pan you have thats a bit hard to answer but 7.5" depth is about maximum for good road clearance
any advice would be greatly appreciated.

thanks,
Richard[/QUOTE]
 
DO2G said:
Hello Grumpy,

Thank you for replying to my thread about 500HP over the weekend. I'm seriously considering taking your advice and buying a BB 496 (I talked to Vortecpro this morning) 650HP and 650 Torque and a set of side pipes.

Does my rearend and half shalfs on my 78 have a chance at suriving? I will spin the tires, but I won't beat on the car.

Thank you

as long as you don,t beat the hell out of the car with hard launches or install big sticky tires the spinning tires and lack of traction tends to act like a fuse and the rear differential will survive for awhile, if you do bonzi launches and install slicks , you can kiss the rear differential and half shafts and u-joints good bye!
I installed a shortened dana 60 rear and 4 link in my 1968 vette after my differential failed but it took an amazing amount of abuse first
 
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