Big Block Swap???
Thread Starter
Pro
Joined: Dec 2005
Posts: 675
Likes: 0
From: Kinzers. PA
Big Block Swap???
Just wondering how hard would it be to swap my 1978 l48 corvette to fit in a Older 427, My dad was going to buy one for our impala its a good deal for what you get its cheap n powerful. But i was wondering how Difficult would it be to fit one in, and make it work without Problems?
Has anyone done this in a Late c3??
Has anyone done this in a Late c3??
Pro
Joined: Jan 2004
Posts: 535
Likes: 1
From: Darwin, Australia NT
One of the biggest headaches in the swap is getting all the pulleys and brackets. Big block vettes used the short water pump where as most other big block applications used the long pump. The long pump setups will interfere with the front crossmember.
Melting Slicks
Joined: Mar 2004
Posts: 3,472
Likes: 18
From: Lake Ozark, MO
It will go right in and bolt up to the existing TH350 (possible weak link)There will be some pulley / bracket changes needed. I don't think the SB radiator will be up to the cooling task. And the rear halfshafts are another concern - don't know what size came in your car. There are issues with the AC/Heater box if you every have to pull the passenger head with engine in the car...you cant get the rear head bolt out without cutting the box.
Instructor
Joined: May 2005
Posts: 184
Likes: 13
Not hard to do but not cheap either. In fact, it can get really expensive. You will have to change all the accessory brackets,pulleys, and belts. All 68-74 BB Corvettes used the same brackets. Take a look in any Covette vendor catalog for the cost. In addition, you will need to change the exhaust and you should consider upgrading the cooling system and adding heavier front coil springs to accomodate the increased weight. This can get really expensive really fast even if you get the motor for free. Take the time to research everything that you will need and the cost for each item then make up your mind.
Thread Starter
Pro
Joined: Dec 2005
Posts: 675
Likes: 0
From: Kinzers. PA
Good advice... The engines a great deal for the power you get, its from guy my dad found. I always wanted a big block vette, theres nothing that can beat it... Now i do plan on buying sidepipes at the end of summer, so exaust till be fine.
I will probably try and make some phone calls and all, If it wont be to much hassle, i mite do it, But cost is a issue yes. I guess ill try and search for prices and everything.
I will probably try and make some phone calls and all, If it wont be to much hassle, i mite do it, But cost is a issue yes. I guess ill try and search for prices and everything.
Drifting
Joined: Jan 2006
Posts: 1,944
Likes: 22
From: Yooperville MI
Other than everything "bigwheel" said, the car is not going to handle (corner) the same with the added weight. Big blocks are capable of huge power for the street/strip (more than the stock driveline can handle) and can be quite thirsty, but todays small blocks can deliver very respectable power for less money and might sip less fuel.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: Jun 2005
Posts: 764
Likes: 2
From: THE OLDER I GET THE BETTER I WAS! NORTHERN ONTARIO
I put a 427 in a 73 a couple of years back no problem...as everyone else says get all your brackets ( short water pump) & re core your rad for the cooling. No problem 
Pro
Joined: Jan 2006
Posts: 599
Likes: 0
From: New York
big block..
the notion of bb's not being good on the turns isn't realy true.....unless your talking nascar speeds on the parkay....the way she sits back in the engine bay n there's realy not a big deal with the weight...maybe 200 lbs wich today can almost b wiped out with all the aluminum parts....there is realy no diff between 3600 n 3800lbs.....i know my big block moves great on the parkway.......like i said the weight issue i think is overrated except in racing applications of course.......what say u guys...
Senior Member since 1492
Joined: Aug 2000
Posts: 87,928
Likes: 156
From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
Originally Posted by jerrylee
the notion of bb's not being good on the turns isn't realy true.....unless your talking nascar speeds on the parkay....the way she sits back in the engine bay n there's realy not a big deal with the weight...maybe 200 lbs wich today can almost b wiped out with all the aluminum parts....there is realy no diff between 3600 n 3800lbs.....i know my big block moves great on the parkway.......like i said the weight issue i think is overrated except in racing applications of course.......what say u guys...
Get the BB front & rear sways, aluminum heads, intake & radiator and you're about the same weight as a SB....you're good to go.
Mash the accelerator and hold on...... 
There's a reason they raced L-88's.
Thread Starter
Pro
Joined: Dec 2005
Posts: 675
Likes: 0
From: Kinzers. PA
well, god this seems alot of work, Would i be better off Stroking my 350, I can buy a kit for 859$ with all my bottom end parts.... Then spend about 1.5k on top end parts..... I seen alot of good deals.. But If i stroke my engine id have to take it to a machine shop for how much work...
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
I say if a BB would have been a factory option for your year (which being a 78 obviously it wasn't) the go big, but since not stick with the SB and stroke it. If you had a 74 or older, then I would say for the BB.
The later C3s will start to appreciate at some point if they already haven't and sticking a BB in a car where it wasn't even an option is going to hurt the value I think. Just my opinion.
The later C3s will start to appreciate at some point if they already haven't and sticking a BB in a car where it wasn't even an option is going to hurt the value I think. Just my opinion.
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
For late C3s I'd just go with a big bore and stroked small block. After I upgrade my heads I've decided I'm done upgrading my 355 and am going to just save up to buy one of those sweet new 454 small blocks. So much power and a lot less effort.
