Nailhead into 1966 Skylark


Hi all, I'm replacing the 300 in my '66 Skylark convertible with a 425 Nailhead & Switch Pitch Super Turbine 400.
I'm in the process of rebuilding the 425 with a complete rebuild kit from T.A.Performance in Arizona,
I've rebuilt the SP400 & fitted a Shift Kit. I've imported a rear sumped oil pan & pick-up tube.
I've mocked up a spare stripped block to the trans & fitted them in the engine bay. I've moved the trans Cross-member back about 4" to allow the oil pan to clear the front cross-member by about 3/4" (hope that's enough)
NOW THE BIG PROBLEM, Engine mounting !!! I know GS parts are what I need, but down here in New Zealand, they're totally unobtainable, & no-one knows much about this swap. I've Googled this swap & seen two different types of frame & engine adapter mounts. I did find a complete set-up including Exhaust Manifolds, but with Exchange rate & shipping & Import Duties, they would cost more than the whole car has cost me. I think I could manufacture these, but they don't show how they fit or what bolts to what or which way round they go ?
I do have a set of Header plates to make up a set of Headers, & not sure how to get around the starter problem yet,(worry about that later)
this car I imported from Bakersville CA & have most of the parts to GS clone it, THANKS
The 65-66 GS Skylark used specific frame pads, adapter plates and motor mounts not used on any other vehicle. Attached are the best pictures I have of mine. I hope they help.


  • 65 GS 040227 Mounts 2.jpg
    65 GS 040227 Mounts 2.jpg
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  • 425 021013 LH Mount.jpg
    425 021013 LH Mount.jpg
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  • 425 021013 RH Mount.jpg
    425 021013 RH Mount.jpg
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  • 65 GS 040815 Firewall Paint 2.jpg
    65 GS 040815 Firewall Paint 2.jpg
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Active Member
The adaptor plates in the picture in previous post can be made. I then used big block Chevy motor mounts and mounted them to the adaptor plates. The frame pads that the big block Chevy motor mounts fit are steel tubing. This will require welding, drilling and a lot of creative thought but Chevy motor mounts are cheap and probably more likely available in NZ than anything Buick. Go with big block mounts because they are built for the larger torque outputs like your 425 is capable of. My wife and I just spent 3 weeks in NZ during Jan and Feb this year. Beautiful country, great place for a vacation except for the looooong plane ride.
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I have MINI-STARTERS for the "Nail" that are MUCH SMALLER than stock & weigh 6lbs. 12 ozs. Others sell mini's also but I AM the originator & MINE FIT & work properly in the GS. That's what they were mainly designed for.