I just picked up a barn find 66 Skylark with the Super Turbine 300 2 speed transmission. Looking to upgrade, any suggestions, insight or advice is greatly appreciated. Current power plant is the stock 300 (4.9L). Just looking for for an upgrade option from stock that is a straight bolt in or close to it that will improve performance and everyday drive ability. Looking for torque converter and rear end recommendations as well. Thanks in advance for your help.
A 200r4 is the perfect upgrade for a small block, Posi and 373 gear would make for an excellent all around package and would definitely give the car noticeable performance improvement
Thank you to @hugger Dumb question because all this is new to me, do I have to change my complete rear end to make it posi or can I achieve this when I change the gears? Any idea if this would be a direct bolt on or do I need to do any modifications, mounts, drive shaft, u- joints, linkage?
The th350 will be cheaper and will require a few minor mods to get up and going, nothing terrible, the 200r4 gets you overdrive but the core will cost few bucks more as will the rebuild vs a th350, but the reward is overdrive and the ability to run a deeper rear gear. Expect to spend $600ish for a th350 and $1000ish for a 200r4. Rear gear parts are available to use your housing and make the posi/gear swap. Or if you have a decent budget get a rear from Brian or JD and just bolt it in and enjoy vs the probable hassle of finding someone capable
The ST300 has the advantage of having the switchable hi/low stall converter. Put a converter from a v6 in there and you will get higher stall. A th350 with a new converter will cost more. 200r4 will require steeper rear gears and carrier to fit them. What's your budget?
The TH350 can use the same driveshaft and yoke. The 2004R will require shortening the driveshaft about 3/4",but is necessary to prevent the yoke from bottoming out or binding up. The lockdown for the TH350 can be attached to the pedal or the throttle. The rear gear ratio will depend more on what you choose for a transmission,and what your goals are with the car. You can build the existing rear that you have,or swap to a 71-72 8.5" 10-bolt.
Thanks to everyone for all the responses. I just got her running after 24 years of sitting in a barn and she runs great but unfortunately now after a couple of weeks and a few oil changes she's making a "rod knock" sound.....I'm considering swapping both the 300 (4.9L) and the ST300 for something with a bit more hp performance. Got a budget of around 4K possibly a bit more, any suggestions or personal experience on a good reliable upgrade for motor and trans for my 66 Skylark?
Are you looking to build something yourself or want an engine/trans to drop in? For the $4k budget you could build a sbb 300 stroker that uses a sbb 350 crank with the TA aluminum Rover heads. With that kind of budget you could even stroke the 350 crank even further to a 3.990" stroke and use a set of nascar take out rods to get the cubes up to 364 with a .050" overbore. You would have to do all the assembly work though and depending on how you buy the heads and level of porting you have done may push the budget number up? There is also the BBB 455 swap to consider as well but to build a performance BBB 455 you may need to up your budget depending on how far you want to take the 455 build. There is also the sbb 350 that is a bit better to start with than the sbb 300 because of more after market support. There is also the Nailhead 401/425 platform that would make a good swap but requires hard to get parts to make it work in your '66. There is also the belly button me too swap, the junkyard LS engine and trans. You swap in an LS, me too! LOL What are your intentions for the car? Just street or street/strip or strip with a little street or trailer race car? Derek
By far, the easiest swap is Buick 350. It will drop right in and bolt up to your existing trans. Or swap in the TH350 trans as well. Very easy swap and won't break the bank. Put a TA Performance 4 bbl intake and a QJet and you will have a very reliable, jump in and drive it cruiser.
Thanks for the response, I'm thinking to swap in an upgrade to the 300. Would love to go with the 455 and TH400 eventually but for now just looking for performance upgrade options other than getting the 300 built up. Wanting a daily driver with enough ponies to spin the tires once in awhile.... Thank you for the response, as I'm pretty new to owning and wrenching on my Skylark do you know of a particular year or Buick engine code for a 350 that has decent performance specs? Or should I look to an engine builder to quote a mild performance build?
