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Big Block Swap

xclr8n

New member
Joined
Jan 20, 2007
Messages
2
Location
BC, Canada
Corvette
72 War Bonnet Yellow (now black)
Hi from a new guy, 1st post

I have owned my 72 since 1991 and my older brother had owned it since 75. It has a 350 rebuilt to 300 hp specs, TH400, 3.08 diff gears, A/C, PB, PS, It has only been used as a daily driver for 4 summers other than that it has been mostly kept in the garage. I now am doing a complete suspension rebuild (front and rear), new SS calipers, rotors, brake lines. Soon a new interior. So this beautiful car will be reborn.

But...

I can't have these kids in Stangs blowing my doors off so I want to put either a blown 454 ( I have a 4 bolt block, steel crank and crappy heads) or get a crate 502 (unblown for now). I am aiming for 550 - 600 ft/lb.

My question is what parts are needed to swap in a big block? ;shrug

I have thought of the obvious:

motor mounts
Rad
valve cover (drivers side)
exhaust (ie headers)
coolant overflow tank
front springs
L88 hood


Thanks in advance, Steve

PS - anyone know how much torque a TH400 can handle ?
 
Joined
Aug 19, 2004
Messages
485
Location
Denver, CO
Corvette
'72 Targa Blue Coupe
Welcome

Hello and welcome to :CAC

I can't honestly say how much torque a TH400 can handle, but I am certain a stock one won't like 600 ft. lbs. But, TCI and others offer nice tranny packages.

You will also have to change alternator, p/s and a/c brackets for this conversion, and probably at least water pump and crank pulleys. I might suggest looking at a ZZ383 crate or 406 or similar, the changes aren't as drastic and you should be able to handle most Mustangs, I would think. It's really up to your budget and expertise. I love a big block car, but-for myself-I question the effort and money required to convert mine from small block, particularly with the offerings as suggested.

My 2% of a dollar, FWIW. Again, welcome and enjoy. Perhaps some others who have done this can offer good advice. :)

Rick
:gap
 

sofast4u

Well-known member
Joined
Dec 4, 2003
Messages
98
Location
NY
Corvette
1069 cortez silver
hey
its prtyyy cut and dry I slipped a 427 in my 69 no problem same trans
motor mounts are the same youll need a 168 tooth flex plate
its pretty piece of cake............ well almost. but well wrth it.
 

Crimson Thunder

Well-known member
Joined
Dec 16, 2001
Messages
814
Location
Orange Park FL USA
Corvette
1970 Marboro Maroon Convertible
I got the new Chevy High Performance magazine in the mail today.It has a nice article on big-blocks you might like.A Turbo400 is a pretty stout trans, it should hold up well if its in good shape.
 

Ed's 1970

Well-known member
Joined
Sep 17, 2006
Messages
87
Location
SoCal
Corvette
1970 Stingray coupe
I'm with u all the way on the big-block.

I am going with either a 496 or 540. A blown 454 sounds awesome though!
My car has a 350 right now and runs good, not enough torque for me though. My other car is a '94 Z28 with a blown 355 LT1, god that car is fast.

I want to retain a 4 speed though, maybe a super T-10?

Anyway, it'll probably be 2-3 years before this car is done. Hopefully there will be some gasoline left when I'm done. :L
 

Garagetoyz

Well-known member
Joined
Sep 20, 2005
Messages
53
Location
New Jersey
Corvette
78 Silver Anniversary 4 spd Crate engine
This is my kind of thread! I hope it goes well, I am thinking of doing the same thing in mine.
 

Rookie Vette owner

Well-known member
Joined
Oct 31, 2003
Messages
130
Location
Upper state S.C.
Corvette
1973 Blue Coupe
Reviving an old thread: Big block swap????

I just got an offer on an old 427 for my 73, it will need to be rebuilt and the earlier notes about the alternator & P/S brackets are good to know. What else will I need say in the suspension area? bigger springs? anything in that area give a clearance problem when you drop the BB in place? How about the aftermarket 700R-4 transmissions, they seem to be able to set them up for the extra power and it should also bolt right in (with the trans-mount they offer).:eek:hnoes
 
B

bmotojoe

Guest
If you’re going with that kind of HP and torque then I would also look into replacing your half shafts from the stock 2.5” to at least 3.0” or 3.5” with solid u-joints. Also look into the safety loop system from Dragvette products. If a half shaft or main drive shaft lets go you can kiss your battery box and anything else fiberglass goodbye without them.
Brian
 
A

Altered

Guest
This is my kind of thread! I hope it goes well, I am thinking of doing the same thing in mine.

Man these guys are reading my mind. I have a 427 that I am considering swapping in also. The very reason the guy was getting rid of the car I have is he said he was tired of getting beat at the drags with it. (I cant believe he didnt add more motor. :D ) Anyway I will not cut my car up but It is suppose to be a #s matching car so this way I can save the original engine. I would do the bigger smallblock but I dont have one but I do have a sweet 427 and I think it would be a blast in my 4spd car. :beer
 

6880 Mike

Well-known member
Joined
Jun 30, 2006
Messages
2,723
Location
The Bluegrass State
Corvette
1968 convertible; 1980 L-82
FWIW: all factory big blocks came with a rear sway bar. You may want to consider adding one.

:)
 

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