Flywheel Question for automatic to manual swap

[BappleApple]

Hey guys! Been a while since I've posted anything on my truck and I need some expert help and advice. I have a built 2nd gen LT1 in my C1500 (Originally pulled from a '92 Corvette) and after 4 transmissions in <6 months, It's became evident that the 700R4/4L60's just don't hold up between the power & weight of an old 1/2 ton truck without being bulletproofed to an extent using a race ready rebuild kit, So I've decided to just go ahead and do away with the crap 4 speed auto(s) entirely

With that being said; I had an old GM Saginaw M15 3-Speed manual transmission still bolted to a spare 327 SBC in the garage I uncovered & pulled out, My plans are to separate them and throw the Saginaw 3-Speed Manual into my truck.
Before I get it torn down, I have to ask you guys this -

Q1 - What do I do about the Flywheel swap?
I'm not so sure the 327's flywheel hub pattern is even the same as a Gen-2 LT1's, And if it does bolt up the next worry I have is that LT1's are externally balanced engines and I'm worried that the 327's flywheel will throw the engine off balance and give me a shake-down. If that happens, Is there anywhere that makes a flywheel for this swap?

Q2 - What should I do about a starter?
Can I use my LT1 starter, or the 327's starter?

Just wanna be able to go fast in my lead sled again, but this time in more than 50 mile increments... lol

Thanks in advance for any help you may have to share, Haven't seen or even heard of someone doing this swap, so the amount of available advice I can find on it is extremely obsolete and old.

Here's a pic of the Saginaw M15 & the 327 SBC.

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[b454rat]

You might wanna rethink using that 3-speed. The gear split is gonna suck, the shifter might be too far forward, it might be real close to being under the dash making it tough to shift. Plus I don’t think they are that strong. I know the 4-speeds aren’t. As for flywheel the 327 won’t work, but get one for the car that came with a stick n double check the balance. Starter could be off same car with stick. Or a mini lol

 

[BappleApple]

You might wanna rethink using that 3-speed. The gear split is gonna suck

You really think so? I was comparing the ratios and I kind of liked where this 3 speed puts me as opposed to the 4 speed auto;

Saginaw M26 3 Speed Manual (1967)
1st- 2.54:1
2nd- 1.50:1
3rd- 1.00:1

700R4 -
1st- 3.06:1 for first gear
2nd- 1.62:1 for second gear
3rd- 1:1
4th- 0.70:1

the shifter might be too far forward, it might be real close to being under the dash making it tough to shift.

Well it's a dual-linkage shift & I have a short throw ratchet shifter for it, Since it doesn't actually bolt into the top of the trans and is linkage dependent, I have alot of freedom with where I can put it as long as I can work the linkages out.

Plus I don’t think they are that strong. I know the 4-speeds aren’t.

You'd be right, Lol. They're no Muncie. These Saginaw's are not too tough in bone stock form (300hp rating), but from what I understand, they can be bulletproofed easier and cheaper then my other transmissions.

As for flywheel the 327 won’t work, but get one for the car that came with a stick n double check the balance.

Figured the hubs were different, So what you're saying is I'll have to get a manual trans flywheel from any 92-97 LT1 and it'll work?


I appreciate the quick reply my guy

 

[Erik the Awful]

You really think so? I was comparing the ratios and I kind of liked where this 3 speed puts me as opposed to the 4 speed auto;

Saginaw M26 3 Speed Manual (1967)
1st- 2.54:1
2nd- 1.50:1
3rd- 1.00:1

700R4 -
1st- 3.06:1 for first gear
2nd- 1.62:1 for second gear
3rd- 1:1
4th- 0.70:1

The auto has a torque converter. You're going to be slow off the line. Also, one-piece rear main seal cranks have a different flywheel bolt pattern than the two-piece cranks.

 

[BappleApple]

The auto has a torque converter. You're going to be slow off the line. Also, one-piece rear main seal cranks have a different flywheel bolt pattern than the two-piece cranks.

Lol true but I figured my power factor would balance it out, It makes just over 500rwhp on 93 octane and just obliterated the tires through 1-3 gear with the 700R4/4L60's with 3.73's in the rear.

Also, one-piece rear main seal cranks have a different flywheel bolt pattern than the two-piece cranks.

Yeah that's what I've found on all the 10+ year old ancient threads regarding it, Haha.
Seems that the LT1/LT4's and ZZ4's were externally balanced and had different flywheel hubs from the old two-peices.
Any suggestion of what to do here?
I'm stumped & I'm worried I won't be able to find a flywheel that will work with this transmission & my LT1.

 

[Erik the Awful]

The taller first gear without a torque converter will mean you either bog until you get up on cam, or blow the tires off.

If it were me, I'd keep the 327/Sag together and sell them to somebody looking for a restoration motor. Put the money towards a 4L80E or an NV4500 to replace your transmission.

 

[BappleApple]

If it were me, I'd keep the 327/Sag together and sell them to somebody looking for a restoration motor. Put the money towards a 4L80E or an NV4500 to replace your transmission.

I debated on a New Venture gear tranny but I wasn't too sure about how good it'll want to fit lol
Also debated on a TH350 Long Shaft or a TH400 Long Shaft, Either trans would be super awesome and good kits are readily available.
Just super hard to find them, Slim pickins where I'm from, Heh

 

[b454rat]

If ur making that power the tranny is gonna go poof in a spectacular fashion, prolly while taking ur feet out at the same time. If yah want to shift then get a TKO-600 or an NV4500. If yah don’t then a 4l80. The flywheel should be pretty easy, I think any small block with a 1 piece seal is technically externally balanced, so prolly one off a vortec motor would work.