LS options for a 1966 Tempest

[Grim66]

Hey Guys, I have a 1966 Tempest that has a OHC 6 in it right now with 3 in the tree. I want to swap that for an LS of some sort and have a 5/6 speed manual behind it.

The car is a basket case right now, but love to get it to the point where it's drivable at least.

If Money wasn't a concern I'd get something in crate form, but alas that is a pipe dream. My question is what kinds of donor cars/trucks should I look at? What do I need to grab from said donor to make sure it's fully operational?
Sorry in advance for all the newbie/dumb questions that maybe forthcoming... new to this and honestly it's been sitting for 10 years so I probably need to get moving on something or it'll forever be a lawn ornament.

P.S. I did search the forums, and there is a lot of info here, I just don't know what's relevant to my situation or not :/

Cheers

[ryeguy2006a]

Your budget will really depend on what the answers will be.

[Canadianwraith]

5.3 LS engines are everywhere and cheap. Get a complete motor with harness ecu and gas pedal. make sure you have the front drive as well. That's the easy part.
Now you'll have to research what mounts, oil pan etc you'll have to change to fit your car.

[stab6902]

My 2 cents would be to stick with the OHC-6 and put a modern transmission behind it. It's a unique motor that's a lot more interesting than a vortec swap in my opinion, and you'd probably save a lot of money too. Check out what Jay Leno did with his 68 Firebird for some inspiration - https://www.youtube.com/watch?v=S5gWSWH053Y

[protour_chevelle]

My 2 cents would be to stick with the OHC-6 and put a modern transmission behind it. It's a unique motor that's a lot more interesting than a vortec swap in my opinion, and you'd probably save a lot of money too. Check out what Jay Leno did with his 68 Firebird for some inspiration - https://www.youtube.com/watch?v=S5gWSWH053Y

A buddy of mine just did a holley 2bbl terminator efi kit on his wifes 67 mustang inline 6. Super cool, starts great, runs fantastic, no hiccups, more response.

[Greaseball]

I'll offer a different opinion than what has been offered so far.....

I have the same engine in a '66 LeMans with a manual 4 speed. Rebuilding these engines is expensive and puts you close to the same money as doing an LS swap with a low-mileage used motor. Now adding a Tremec 5 speed is a straightforward process. Tremec now has the narrow-body 5-speeds so you don't have to cut your floor up to clearance for the transmission.

The OHC-6 was an advanced engine when it first came out. It's a novelty engine now. Plus upgrading these engines for more hp/tq is limited unless you have the $$$ or the talent for building custom stuff. Heck, even part of the valve train on Jay Leno's rebuild required custom-made parts to OE specs because some of these parts are just not around anymore.

Now, if you like to tinker more than you want to drive, then my opinion isn't for you. As for me, I'm the opposite. So did I take my own advice? Yes....kind of. I'm not dropping in an LS engine, I'm working on a Gen 5 LT1 swap. Let me know if you want a decent runningSprint optioned OHC-6 motor.

[79 Camaro]

I'm a LS guy so that's the way I would go. So many LS engine options out there.
I've bought crate GM LS engines and low mileage salvage yard engines. Only got burned once on a "low" mileage LS.
Really depends on you project goals.
6.0 or 6.2 LS would be my choice. Stick or auto depends on your likes.

[Jk918]

I'd go LS 5.3 or 6.0 out of a running pickup or a swap yard, you can run a carb intake with a carburetor and retain your original pedal and linkage. Could even run a muncie 4spd to help keep cost down

[Alwhite00]

If I were to do it again I'd get all the Holley swap stuff. I did my 67 chevelle about 7 years ago. I used the Holley 302-2 pan and it fits great. I used a 6.0 out of a truck, LS6 cam, ported heads, LS2 intake, headers. I love this engine and on trips it knocks on 23mpg. I put 4,800 miles on it last summer without a hiccup.

[Lonnies Performance]

Budget tells all.

As stated above, the 6 speed will require some floor mods.
If you are determined, then the logical choice may be a 5.7/T-56 from a 4th gen Camaro/Firebird.
Unfortunately, they are getting rather expensive/hard to come by.
I cannot vouch for the 4th gen F-body accessory clearance to steering box in an A-body.

The newer 6 speed Camaros (5th gen) will come with the 6.2, but also have more sophisticated electrical needs, drive by wire throttle etc.
The TR-6060 has an odd rear drive flange that requires special driveshaft components.
Also, the 13 up are electric power steering so the drive system will need additional parts.

If you don't mind a 5 speed then any LS will do that meets your budget.

The Vette front accessory drive system is the most compact & you can buy it separately, but at about $700.
The trucks have the ugly intake manifold & the worst front drive system.

If you don't mind piecing it together then maybe look for a Vette 6.2 engine with front drive accessories & mate it to a TKX 5 speed to keep from cutting the floor.
You may also be able to source regular mechanical clutch linkage etc. from an A-body

[chpr1972]

Use the new 5 speed TKX. I have the TKO600 {5 speed] in a 66 Lemans now. A 6th gear is not most of the time anyway. There are 3 of them. Get the one with the best highway gear, not the autocross gear. The trans has been redesigned for better shifting and fitting in a tighter space. After deciding what tire/wheel you want to use , Diameter matters, then change the rear gear ratio to a 3:55 or 3:70. 3:70 gears with a 25.5" tall tire puts me down the highway ay 1,800 to 2,200 RPM [60/70 MPH] You are probably running under 3:08 gears [326 automatic was factory 2:56 rearend ratio ]
You will have to get a new driveshaft, as rear yoke is different and trans longer than yours, move/ modify or replace the crossmember backwards.
You might just consider running the 4L60 4L80 transmission and use the factory computer. That is what I plan to do. LS6.0 4L80 trans with a stage 2 Brian Tooley cam/kit. I haven't done this yet as I an recovering from Knee replacement surgery but I have the parts.

[chpr1972]

GET THE SERIAL NUMBER OF THE VEHICLE THE MOTOR came out of. Only way to know motor size as 4.8/5.3 are marked the same. Get motor and accessories as they are expensive! 2000/2002 LS motors were mostly manual cable throttle bodies. Blue/Red computer boxes. Blue /Green boxes were drive by wire. You will need at a minimum, computer, throttle cable, tach box behind the dash. The wiring harness can be bought ready made, but people have also saved themselfs $5/8 hundred bucks using the harness. Some newer motors have fuel saving feature that shuts valves off thru the lifters. That started in about 2005. The iron motors are good and cheaper. They all have aluminum heads, and intake must match. Truck intakes are ugly, but they give better low end torque. But to me, all the intakes are ugly! I am going to a LS 6.0 as I am taking out a BBC torque monster.

[chpr1972]

Costs and problems that I know of. YOU WILL MOST LIKELY HAVE TO PAY A TUNNER AFTER THE SWAP! $500 + oil pan kit Holly. $450. Tie rods are hitting a lot of oil pans on full turns. Holly is suppose to have fixed it. Aluminum not steel. Cam/kit$400, Adjustable motor mounts to slide $40 Frame mounts SSC $80/90 and motor mounts SSB $30 Pr rubber I will use} $90 performance. Exh manifolds $300. Now you have to change over to electric fuel pump. Mine for my car {I run Holly HP EFI now} Tank and pump $600+ Hoses ? Corvette fuel regulator and filter $300/350 Larger radiator for LS ? If you use the automatic, cooler lines fittings lines to radiator. Look up what people are using for electric fan. Then you have the usual new front/rear main seal while apart. I HAVE NOT DONE this swap YET! but I hang around a tunner shop, and talk to people . Yes, I know, REAL HOTRODS have 3 pedals! But if you have a wife, girlfriend it makes it friendier for them to drive!

[Vimes]

I have a different take on this - find a used car or truck with the configuration you want, and buy it. A donor will have almost everything needed to make the conversion, and you can part the car out when you're done to make up some of the money spent. Plus, you might even be able to make use of interior or suspension parts to improve yours.

[68Formula]

GET THE SERIAL NUMBER OF THE VEHICLE THE MOTOR came out of. Only way to know motor size as 4.8/5.3 are marked the same. Get motor and accessories as they are expensive! 2000/2002 LS motors were mostly manual cable throttle bodies. Blue/Red computer boxes. Blue /Green boxes were drive by wire. You will need at a minimum, computer, throttle cable, tach box behind the dash. The wiring harness can be bought ready made, but people have also saved themselfs $5/8 hundred bucks using the harness. Some newer motors have fuel saving feature that shuts valves off thru the lifters. That started in about 2005. The iron motors are good and cheaper. They all have aluminum heads, and intake must match. Truck intakes are ugly, but they give better low end torque. But to me, all the intakes are ugly! I am going to a LS 6.0 as I am taking out a BBC torque monster.

Good info.m but one correction the 1999-2000 LQ4s did come with iron heads. They also had a thicker rear crank flange which needs to be considered if adapting a transmission that is anything besides a 4L80E from those same two years.

[ProTouring442]

An Atlas 6 can be had quite cheaply and would fit the Sprint 6 idea very well.

Just a thought.

[Grim66]

Wow so many great replies! Thanks a ton. I considered keeping the 6, but honestly I'm old enough to be firmly entrenched in the "There is no replacement for Displacement" camp...



At this point It's been sitting out in the yard for over 10 years, If I don't do something soon, she'll probably never see pavement again :( I think the fastest way would be for me to get a donor, much as I would love to go full computerized with it I'm probably going to look for something a little easier for me to understand and work on myself.