GS exhaust manifolds v Headers and misc questions 401 swap

[crabboyjimmy]

Getting ready to drop a 401 out of a 63 Riviera and st400 off of a 401 out of a 66 Riviera into my 66 Skylark where a 300 used to reside. Got a few questions.....

   I've got the pilot bearing adapter,  flywheel and starter off of the 66 motor to help mount the tranny to the motor. The torque converter is huge ( pulled the tranny out of a 66 Riviera). Should I go with a smaller one since I'm dropping it in the skylark?

   Do I need a cross flow radiator? Or can I just go with a 3 or 4 core aluminum one?

   Im got the original riviera exhaust manifolds. Should I just go with those and modify my existing pipes? Go with Headers( long tube, short tube etc and which ones will work for the skylark)? Or wait for a chance to pay an arm and leg for the 65-66 GS ones that occasionally appear?

   I have the motor mounts and a template to fab the frame pads. Anything else I need to have or do to hold the drivetrain in place other than move the tranny mount back?

   Ive already moved the battery tray for the dif side starter

  Any input or suggestions are always welcome and thank you in advance.


Jimmy

[jmos4]

Hi,

Is the trans a switch pitch (st400), 65 or 66? If so you can install one from a switch pitch 300 2 speed trans which will give you a little more stall speed. If your trans is a th400 or a 64 you should be able to use an aftermarket one with the stall speed that works for you engine/rearend ratio.

Riviera exhaust manifolds won't work or fit in a A-body. You either need 65/66 Gran Sport manifolds or aftermarket headers.

As for mounts it might be easier finding 65/66 Gran Sport mounts and adapter plates.  Trans mount will require you to move the cross member back a proximity 6 inches if my memory serves.

You might want to check out the site or V8 Buick site as this conversion has been done a lot just requires a lot of specific parts.

Good luck with the project.

Regards,

[Dr Frankenbuick]

You will need a rear sump oil pan and pick up if both of the engines are from Rivs.

[GS66]

While you're at it put in a mini starter, it will save headaches down the road. GS manifolds and long tube headers are both expensive but I would not use the shorty headers for a Skylark.

[Nailhead]

While you're at it put in a mini starter, it will save headaches down the road.

Can a mini starter be removed without interference requiring other stuff to be removed or the engine jacked up?

[Mark Ascher]

While you're at it put in a mini starter, it will save headaches down the road.

Can a mini starter be removed without interference requiring other stuff to be removed or the engine jacked up?

Yes.

Mark

[Loren At 65GS]

Everything I have been reading about '63 and earlier nailheads is that the end of the crank is different than that used in '64-'66.
Because of that, the '64-'66 transmission will not bolt directly up.  It requires a special adapter that bolts to the crank and the flex plate bolts to that adapter. Something to look into.

 Loren

[crabboyjimmy]

  Sorry, I forgot to mention Ive got the rear sump pan and pick up too.  That was def a surprise I wasn't expecting.... 
   And too clarify, I CAN use the converter from the 2 speed power glide in my 66? I was told that I just need to swap out the pilot bearing and grind something off the crank.  Ill go out and look at them later today and double check

   A member of the V8 buick site turned me on to these. I thought it might be easier to fab them than find them.

Thanks again for all the help !

[WkillGS]

Torque converter- The Riviera one will work, it has a lower stall speed than the smaller converter used in the GS. You can use a smaller converter from a 300 or 340 engine which will give you a higher stall speed. My GS has about a 2000/3000 stall speed in low/hi. The Riv converter will be a few hundred rpm less. A converter from a V6 will have an even higher stall speed.
The smaller converter has smaller diameter mounting bolt circle. Your '66 flexplate may have mounting holes to fit the larger and smaller converter. If not, you can drill holes to fit the smaller converter.
Engine mounts- Do you have the cast iron frame pads? they were 65-66 GS only. Repo rubber mounts are avail from the Buick Farm. You can make the adapter plates, as you know.
Radiator- Yes crossflow. The nailhead has the inlet/outlet on opposite sides compared to most GM's. You can either get a reproduction 65-66 GS radiator, or get a universal aluminum radiator. A universal for a mid-60's Ford- Mustang, Torino, will have the in/out on correct sides and fit in the Skylark radiator support. I've had good performance from an aluminum Griffen I bought over 10 years ago, but there have been a lot a lot of complaints about ones made after that. You can use a separate tranny cooler if you don't have one built into the rad.
Exhaust- There were some GS manifolds on sale on V8Buick. $250, which is a good price. Headers will cost much more unless you can find used ones. Ground clearance has been a problem on some headers especially if suspension is lowered or you have short tires on the front.

A repo engine wiring harness for a GS would be the easier solution. Don't know what is involved in adapting a 300 harness. The GS uses a junction block/horn relay on the inside drivers fender for the junction of the battery cable, engine harness power (alternator) and the feed to the main harness. You should add a fusible link between the junction block and the main harness as a safety feature, Buick started doing that in 1967.

[Loren At 65GS]

Here is a link to some good information from Russ Martin.

http://nailheadbuick.com/tech-info/automatic-transmission-options-for-the-nailhead-to-get-rid-of-the-dynaflow

As Walt pointed out, the cast iron frame pads are specific to the '65-'66 GS and are somewhat difficult to come by.

As for the engine harness, there is a considerable amount of difference. There are only a few pieces that I reuse from a 300 harness to build a 401 harness. I would need to look at the two different connectors again , I'm recalling some differences in the layout of the wiring at the fuse block.
The detent switch from the Skylark can be reused , as can the kick down switch. You will need the correct kick down bracket though.

 You will need to move the battery to the driver side, requires two unique battery tray mounting parts. Again, '65-'66 GS unique.

 Loren

[WkillGS]

For, 66-67, the battery tray bolts directly to the fender/ rad support- no brackets necessary! 66-67 use the same battery tray, but the holes are different between the two. Repos are avail for '65 but not for 66-67.

[crabboyjimmy]

   Getting close to maybe actually pulling this off. I Actually had a radiator here that fits ! Someone gave it to me for my elcamino and the pipes were on the wrong sides     I ordered a PerTronix Ignitor III to put in my stock distributor with their Flame Thrower III coil with new suppression core plug wires. And I got lucky and got a good deal on a 750 cfm Rochester off a 66 wildcat. If theres anything that I might be missing, or still need to change, I would appreciate any input.


Many thanks,

Jimmy

[elagache]

Dear Jimmy and mid-60s Buick restorers,

   Getting close to maybe actually pulling this off.

Definitely you are making progress!  You'll have to a wait for the 66 experts to chime in on any of the details, but thus far it looks like you are on course for completion!

Cheers, Edouard 

[crabboyjimmy]

   Yeah... I know its " www.65GS.com"    but you guys and V8buick have been immensely helpful with helping me figuring this out.   Im sure there's going to be a couple hundred bucks worth of "extras" that are going to pop up. but Im hoping Im over the big money hurdle now.