Just looking to gather some information on this topic. Have any of the forum members done this??

Thanks Chris

 

Check the engine mod forum. I THINK it was there that this was recently gone over, guy has a wild BB in his C4, talks about fit issues, etc.

:cheers:
Matt

 

Chris just go to pureperfection.net check out the Money Pit.

 

swapping a bbc into a C-4
swapping a bbc into a C-4? heres whats needed,first if you put a bbc with aluminum heads, intake and water pump in , in place of the standard iron small block you only gain about 50-70 lbs, not enough differance to cause any problems at all, , I have worked on several of these swaps now and Im in the process of getting ready to do another one,heres whats needed

steering rack mounts cut and rewelded 3/4" farther forward (that of course means the power steering pump lines need to be extended 3/4" also)

small notch (starting at rear and going 3" forward from rear edge X 3/4"deep X 5" wide works well in rear top surface of (K) frame cross member to clear damper and pulley)(if you use an internally ballanced big block with the 6.75" dia. damper you can most likely skip the notch but with the 8" dia damper its necessary, and some oil pans will also require the back 1 1/2 of the (K) frame to be notched at an angle slopeing to the rear to clear them so youll probablly need the notch of some kind anyway)(and yes before you ask you could shim/modify the motor mounts up to get the clearance, but that would slightly raise the weight center and slightly effect the handleing, and that also makes the windshield motor and distributor clearance a bigger problem)

air conditioner shrouding fiber glass on pass side foot well around the air conditioning on the firewall needs to be modifyed for clearance, (the fiber glass cover from a LT5 makes this easy)(evaporator houseing cover)

1971 bbc vette exhaust manifolds and all brakets/pulleys (mods needed here)

oil pan needs to be only 7.5" deep max

3" hood scoop unless you run a low rise intake and carb or a low height efi system

for a step by step instructions with pictures get a copy of the august 1998 vette magizine article( starts on page 34)it helped quite a bit the first time

otherwise its almost a drop in deal, but keep in mind that youll need a bigger radiator, the trans will not last to long with that amount of torque and it may not pass emission testing and a small size starter is needed, and your windshield wiper motor needs to be replaced with a much smaller one,(I don,t remember where we got them but alittle measureing and a trip to the salvage yard took care of that problem, and no tall valve covers don,t work well!

btw install the short block then add the heads with it in the car its FAR EASIER THAT WAY than trying to install the long block

BTW the earlier cars like the 1984-86 (Im not sure what years exactly)dont have the heavier forward frame braceing above the stearing rack that makes this swap more difficult to do! I have worked on this swap on the 84, 85, and 86 cars so I know they work fine, the later cars like the 1992 with the heivier forward frame braces above the stearing rack look like they will be more dificult but still do-able with some extra work, btw theres a guy at ARIZONA SPEED AND MARINE that has one you might want to talk to .

 

Dumb question.

Why build a big block? You can get huge cubes out of a small block, and not have to deal with the extra weight of a big block up in the front of the car.

Plus... aren't small block parts cheaper?

Doesn't make sense to me, with guys getting 700+ RWHP out of 402 ci LS1 motors....

 

you can make a 406 or a 409 (can't remember) out of an LT1/LT4 .. that should be plenty.

 

some guys like big blocks besides theres no way in hell your getting the torque and hp curve out of any sbc that you could get out of a 572 bbc with the same type mods done to it! with a good shot of nitrous or for that matter probably off nitrous, with a turbo or off those extra cubes make a differance, here think about what dropping one of these in your vette would do for its performance
http://www.sallee-chevrolet.com/Sneak/Previews.html


Horsepower……………………………………720 @ 6250 RPM
Torque………………………………………………685 Ft. Lbs. @ 4500 RPM
Max. Recommended RPM…………6750 RPM
http://www.skunk.net/boatengines-496.htm
stick this injection system on it it firs under the stock hood and gains even more torque

698" Big Chief- Dual Four Barrel Special SAR Aluminum
Block Pontiac 1220 HP or Big Chief 1240 HP

and of course theres always turbos and nitrous you could add :D
sure its crazy but increased displacement DOES have an advantage and once you pass about 600hp building a bbc is going to cost about the same or less than a big block to reach the same power levels
now as far as weight goes, if you use an aluminum water pump and heads and intake youll be within about 80 lbs of a sbc, use an aluminum block also on that bbc and youll be lighter in weight than a sbc


[Modified by grumpyvette, 2:07 PM 10/8/2002]


[Modified by grumpyvette, 2:10 PM 10/8/2002]

 

What Patrick said is correct. I have a 396 in my car. GMPP just came out with a new block that is killer with 4 bolts on EACH cap and the center three outer bolts are splayed. What's more is that is has a once piece rear seal and can be bored to 4.155". So you can easliy build a 427 small block with this block bored to 4.125" and use the new Eagle 4" stroke 1pc seal crank. There is your 427 for alot less hassle than a big block. The down side of this set up is that the block is $1900.00, but the crank is only $700.00.

 

Playing devil's advocate with engine swaps....

Since the Buick/Olds/Pontiac 455 V8's weigh less than the BBC (70 lbs I hear), why doesn't someone think about swapping one of those things in? That could be a lot of fun. I know they're wide as heck compared to a SBC but probably not as wide as a BBC. Surely there's a B.O.P. bellhousing for the T-10 (4+3). Wouldn't have the hydraulic slave mounting provision though. Using a 700r4 or ZF6 would be trickier.

I know it's been done already but I really think the Buick Turbo V6 would be perfect in a C4. They're much smaller than the SBC and the Buick can make insane amounts of power on the stock shortblock. With the shorter, lighter V6 motor mounted as far back as possible we could probably achieve a perfect 50/50 F to R balance.

 

Did this swap on a customers car (it was more of a race car).

Details of my experience doing a C4 BBC swap:

1) Custom headers make the swap a BREEZE. (I have some custom used 2" jethot coated longtube headers for sale for a BBC c4 swap for sale, email me ltmotorsport@hotmail.com) They give you more room than the small block headers did! you can work on the motor EASY.

2) Dont move the rack. Just use a flat single groove crank pulley, short 64 396 chevelle style water pump (use pulley spacers to line up) and make your own altenator bracket etc.

3) Take out the A/C box and life is easy.

4) The windshield wiper motor is going to hit. i just took it off.

5) Use the stock small block motor mounts bolted to the BBC engine.

6) Cowl hood or a REALLY low intake.

The headers are the hardest part really. Its really just a drop in easy swap.

The car weighed 3300 lbs (/w driver) and dynoed 468 rwhp on motor. It ran a 10.7 @ 125 on pump gas. 12 mpg. Dana 44 3.73 gears, TH350 3500 converter.

 

How much for the headers????

 

so it can be a very easy swap? i was thinking of doing a 396 LT1 this winter, but i have long wanted a 502. you think the difficulty would be fairly comparable?

 

Well, dija know GM's bringing out a new BB cratemotor?

It is a 572ci big block crate engine making 620hp and 650tq. It is low compression at 9.5:1, has AL heads, steel crank, and other good stuff and make the rated power on 93oct pump gas.

Edit: D'oh! I shoulda read the whole thread first. :cheers:


[Modified by RocketSled, 8:18 PM 10/8/2002]

 

I did it... You can go to my website to see some pics of my application (My wife does websites specific to cars BTW). I did most of the work myself at my house and by no means was it a quick fix. Mine has been down for two years (just got it on the road last week thanks to some tech guiding from GRUMPYVETTE thanks Paul!!!!) because of many obstacles that crop up and not to mention this motor does NOT FIT easily to c-4 applications-start praying for patience tonight- you'll need it. As Paul said, its do-able. Depends on how deep your pockets are (whether you do it yourself or if you send it out professionally to be built) and the long haul of headaches that will definitely come. In the end, I have much, much more horsepower to the rear and it turns lots heads. I have no regrets to the project at hand because you never can lose sight of your dream. One thing for sure, there is nothing to compare to the sound of a BBC when you turn the key - make no mistake. So get to wrenchin' and if i can be of any assistance, give me a holler!

 

I didn't realize that there were so many big block c4's. Lets start a big block registry!!