Topic: TH350 to Muncie Swap Help Needed!

[Atticus80pacecar]

First time posting here, looking for some help with my project - 1980 Pace Car, swapping the 301t and th350 for a 400 and 4 speed Muncie wide ratio m20.

I've got the motor and trans into the car, and am now starting on swapping the pedals, and figuring out the clutch, and shift linkages.

Does anyone have a photo of the Z bar setup & clutch linkage, and shift linkages installed on the car? I have no idea how it all hooks together, and some good pictures would help greatly!

Also - Will the yolk and driveshaft length be the same between th350 and the m20?

[Maxthe222]

Why to a pace car with the original driveline? There are plenty of pace cars with blown motors that could benefit from a different engine, but why to one that's still got the driveline?

[b_hill_86]

I’m not positive about the M21 but when I swapped from my TH350 to a BW ST10 I was able to use my old driveshaft but I needed to switch the yolk cause those are not interchangeable.

As far as the linkages, I don’t have any pictures to post nor a way to post them but those areas aren’t real conducive to being photographed cause of the tight quarters anyway. I’d be happy to try to answer any specific questions you might have if it would help. Worst case I could try to take a couple pics and email them or something if necessary.

[Atticus80pacecar]

Thanks for the input!

I found where the z bar bolts to, and I know where the clutch pedal linkage attaches to the z bar. Is there just one more linkage that goes from the z bar to the clutch fork?

Also, I got my parts used so the linkages don't have pins (assuming any cotter keys would work) or any washers etc. Am I missing little bits to make all that tighter or is the whole setup just sort of floating (for lack of a better word)? Seems like there would be a lot of "play" if every linkage connection is just a stud with the pins keeping it from disconnecting.

I assume the t10 has a slightly different shift linkage setup so I don't know how helpful pictures would be in that case anyway.

[Atticus80pacecar]

Maxthe222...

That is a valid question, and one I struggled with for a few years before I decided to go for the swap. I realize the collector value aspect, but Ill be keeping the original motor/trans just to have it for that reason. I got the car from my aunt when I was 15, its never ran great, even for a 301. I have no intention of ever selling the car so its worth more to me with the motor and trans that I want. Up until now it wasn't really in shape enough to drive more than 20 miles from home. A trans am should have some muscle IMO, and the 301 is NOT the motor for that 

Besides the hole in the floor for the manual tunnel hump, everything I'm doing is reversible should I want it back to original.

301t < '72 400 block (bored to 413 with a hotter cam), 68 GTO heads

[b_hill_86]

Yea there should be one more rod from the bottom arm of the zbar to the clutch fork. It’s adjustable. Looks like this if the link works. https://www.summitracing.com/parts/oer-3849703?seid=srese1&gclid=EAIaIQobChMIwKXppIzD6AIVxICfCh2usQzyEAQYBCABEgJ5ofD_BwE

Cotter pins would work but the pins in this kit are what are supposed to be used. Sorry I couldn’t find a better picture at the time. https://www.classicindustries.com/product/1967/pontiac/firebird/parts/k710.html

Those can be bought separately. I just can’t remember where I got mine and I can’t look right now. I don’t believe there are any bushings used but don’t quote me on that.

[Atticus80pacecar]

Thank you for that info, I'll track down some clips of that style.

Another question, do I NEED a neutral safety switch? As it was an auto car, would there even be a place to wire up that switch to? I realize the inherent risk, just speaking as to whether it's necessary for the car to turn over.

[Wallington]

Don't worry about reversible or storing an unwanted engine. It will never find its way back.

[b_hill_86]

No. The neutral switch (and reverse lights) are part of the collar on the column that would turn via linkage (backdrive linkage) atttached to the auto shifter (at the trans I believe). I left mine that way when I swapped. The correct way would be to put a clutch safety switch which would take the place of the neutral safety. I believe there was also still some backdrive linkage attached to the reverse linkage on a 4 speed that would require you to put the vehicle in reverse prior to starting (or maybe in order to remove the key). Don’t quote me on that last part. Aus or someone else may know for sure.

But the ultimate answer is you can leave the neutral safety alone. Just make sure your collar is rotated all the way counter clockwise. Your reverse lights won’t work in reverse though.

[Atticus80pacecar]

Oh, I meant clutch safety switch, not neutral safety switch, but you answered it anyway thank you. That is all great info to have I appreciate it!