Jim’s Blog: Are Engine Swaps OK?

Small block, big block, and LS Chevrolet V8s tend to find their way into all kinds of classic cars. Should they?

I’m all about making a vintage car more drivable — from steering and brake upgrades all the way through the addition of modern fuel injection. All of these things can make a classic car more usable in today’s busy traffic world. But what about that engine?

I’ve been talking with ACC columnist Jay Harden about this at length lately. His ’69 Chevelle has a big block in it now. He’s been tossing around the idea of converting the car to LS power, which has a lot of benefits in both grunt and economy. But there’s just a certain sound and presence that a classic Mark IV big block brings with it, and he’s worried about losing that stoplight X-factor.

Now, engine swaps are pretty black-and-white when it comes to cars like his. His car was a small-block 307 from new, so why worry about pulling out the 454 that wasn’t there originally? But if his car had been an SS 396 car before he built it, I’d feel differently. 

Sure, you can yank out a factory block and store it. The 396 shares its basic design with Chevrolet’s other big blocks, so there’s nothing from stopping you from installing any other engine from that family for daily use — the only real difference you might run into is in motor mount placement with Gen V blocks. But an LS swap? With the right components, an LS will simply bolt in, too — but you’d need to make a host of other changes that could be hard to reverse. For me, installing an LS would be a no-go on a “special” car like an SS 396. But on a 307 car? Go for it.

When you’re looking at a car at auction, when does an engine swap start to bother you? Are you all about modern usability with multiport injection, knock sensors and computer-controlled timing, or would you rather see most cars — if not all cars — left with the basic engine configurations they had when they were new? What’s really gained and lost in losing an original mill in favor of something newer?

Let’s talk about it in the comments below.

3 comments

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  1. Thinking of installing a ‘426 Hemi’ or a Packard-Rolls Merlin or maybe even Chrysler Turbine Power in your 1903 Pierce-Arrow ? Wow – there’s a new Category (Jay’s probably doing
    it right now in his 190? Baker Electric !)
    Seriously now – DOES ‘ORIGINAL’ mean ‘ALL FACTORY ORIGINAL’ , UNLESS OTHERWISE STATED – BEFORE YOU
    INSPECT & OPEN THAT HOOD at Shows or DOES IT NOT?
    Rescue the Restorers?
    Now that every abandoned, parts sourced, junk value & formerly partial bodied collectible related hulk can be imaginitively turned into a new type of ‘APPEARANCE
    SIMILAR COLLECTIBLE’ (and some ARE IMPRESSIVE AS CUSTOMS – MOD MUSCLES & CLASSICS) – can bring more $$ at Auction than formerly, Top Tier, SHOWCAR CONCOURS Actual Matching #s ORIGINALS – what’s NEXT?
    I’ll go for ‘CREATED COLLECTIBLES’ !

  2. Thinking of installing a ‘426 Hemi’ or a Packard-Rolls Merlin or maybe even Chrysler Turbine Power in your 1903 Pierce-Arrow ? Wow – there’d be a new Category (Jay’s probably doing
    it right now in his 190? Baker Electric !)
    Seriously now – DOES ‘ORIGINAL’ mean ‘ALL FACTORY ORIGINAL’ , UNLESS OTHERWISE STATED – BEFORE YOU
    INSPECT & OPEN THAT HOOD at Shows or DOES IT NOT?
    Rescue the Restorers?
    Now that every abandoned, parts sourced, junk value & formerly partial bodied collectible related hulk can be imaginitively turned into a new type of ‘APPEARANCE
    SIMILAR COLLECTIBLE’ (and some ARE IMPRESSIVE AS CUSTOMS – MOD MUSCLES & CLASSICS) – can bring more $$ at Auction than formerly, Top Tier, SHOWCAR CONCOURS Actual Matching #s ORIGINALS – what’s NEXT?
    I’ll go for ‘CREATED COLLECTIBLES’ !

  3. Well, I have the best of both worlds. I have a 61 Buick with a LS and a 69 427 Corvette that I was able to add other upgrades to. I feel that with both, and mostly for the other older cars I have built that the way the power meets the pavement is more important to me.
    In past builds the first thing I did was to install an over drive transmission. But in the case of the 69, it was a 427 390hp, M-21, 411 factory side pipe car. It was great for stop light to stop light, but anything else your ear drums would begin to bleed with the high RPMs trying to keep up with freeway traffic. I switch out the gears and then lost the stop light torque, which convince me to install the Richmond 6sp. I now have amazing torque and over 20mph on the highway. I have also installed an aftermarket air and not miss any performance and I am finishing up a Holley Sniper EFI, which should still allow for proper hood fit, a factory look and smooth acceleration.
    For my Buick I have a LS that is about 400hp (not much different than some of the ratings of a Nail Head). I brought it already installed and have had to put money in the wiring in the engine since the automatic cylinder saver (8 to 4 depending how driven) has caused some lifter problems, and you don’t have that cool looking nail head when you pop the hood,so I could have gone with a Nailhead with a EFI. However the 6L80 I can’t live without. The torque range and highway driving is amazing. I am starting back on my 77 Y82 this fall and although I have all of the original components rebuilt and ready to go, I have decided that both the 6L80 and the Holley EFI will be installed to give me a more reliable and enjoyable experience with it. So, the heart is a major decision, but the legs need to be explored as well.