If I understand correctly, the Gm light-weight flywheel came stock on L69 cars. Would that flywheel work well with my current set-up (see sig) and 3.23's. Would it work well with a 350 swap? The car will never see a drag strip.

JamesC

 

Should work just fine. Works on my 400......

 

How would this work compared to my Hays Billet flywheel(30 lbs I believe)?
Would i see better throttle response?
Do you have a part#?
thanks
Steve

 

it'll work fine. A little tougher to launch consistently, but a little more throttle response.

 

I wish I would of went with a lightweight flywheel but i alrdy bought a stock one and had it balanced with my bottom end.

 

This from GMParts Direct:

GM PART # 14085720
CATEGORY: Engine Flywheel
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $211.05
OUR PRICE: $147.74
DESCRIPTION: FLYWHEEL
Outside diameter is 12 3/4" for years 1955-85. Crank Flange bolt pattern: 3.58"; clutch dia.: 10.4"; starter ring gear teeth: 153. Lightweight nodular iron flyweel. Weighs approximately 15 pounds. For two piece crank seal

Any other comments about the appropriateness of this piece for my car would be appreciated.

JamesC

 

What about for a 1 peice

 

You might do a search if no one kicks in. I recall seeing some part numbers, but since they weren't of personal interest, I blew them off.

JamesC

 

I don't think it matters whether the crank is a one piece or two piece oil seal crank...

I'd think it does matter if it's internally or externally balnced though.

 

305TPI 5speeds had the 16lb flywheel, however 305TBI 5speeds got the heavier 25lb? flywheel

i have tried both, obv the heavier one gave more torque, car revved quicker with the lighter one.

 

SLP,

What kind of gearing did/do you have? Which flywheel are you currently running? What's your preference?

JamesC

 

3.08 and 3.27 gearing. id use the 16lb one. my car is apart right now but the 16lb wheel will be going back in along with a spec stage II clutch

 

So I should be good to go with 3.23's? Any downsides to the lighter version? Driveability and so on? This is strictly a street-driven car--but I'm always up for a bit more zoom zoom, especially on the highway.

JamesC

 

Confuzed I think they bolt up different.

 

So i guess if i went with the lighter flywheel after having it balanced with the heavy one ide screw it up?

 

this is the info I found on the lightweight ONE piece rear seal flywheel
#14088646 Flywheel
Outside diameter is 12 3/4" for years 1986-up. Crank Flange bolt pattern: 3.00"; clutch dia.: 10.4", 11"; starter ring gear teeth: 153. Lightweight nodular iron flyweel. Weighs approximately 16 pounds. For one-piece crank seal
Hope that helps,
I believe I'll be buying one and selling my Brand new Hays billet..live and learn
Good luck
steve

 

Well, I guess there is a difference then - I just don't know what it would be though. I stand corrected! Live and learn...

 

Oh, and BTW Spdfrk1990 - Cincy's near and dear to me since I was born/grew up there. Nice to see someone from there on the boards. I still go there for family pretty often... Who Dey!

 

Cincy is starting to bother me though im rdy to get out of here. Soo does anyone think ill be better off if i use the lighter one even though its been balanced i might just call the company that did it and see what they say. That 25lb er is a lil too heavy I would think the 16lb one would help alot.

 

"The bolt circle on the crankshaft flywheel flange is different. Pre 1986 2 piece RMS is 3.58" and 1 piece RMS cranks have a bolt pattern of 3.00". Also cranks with 1 piece seal require a counterweighted flywheel for proper engine balance"

 

question, does the 16 lbs flywheel for 86-up bolt up to LT1 style T56?

 

https://www.thirdgen.org/techbb2/sho...hreadid=270645

The LT1 flywheel is deeper than the 85-down 16lb flywheel.

The 86-up 16lb flywheel is functionally identical to the 85-down 16lb flywheel except for bolt pattern and balance.

Therefore, no it does not.

 

I run the factory 15/16 lb. flywheel on a dead stock 305 with WC T5 and 3.73's--absolutely no problem off the line and much quicker throttle response. I'll keep it when I switch to 3.23's.
I also have a 36 lb. Hays billet steel flywheel gathering dust--shatterproof, but it made a hot rod '56 'Vette run like it was made out of lead--switched back to a 15 lb. flywheel and it flew.

 

Has anyone switched from the 25lb to the 16lb and had any balance problems.

 

i know this from experience :lala: i didnt know it was a t5 flywheel though ruined my clutch, and had to do it all over again, the dish clearance for the diaprham/flywheel bolts is what the problem is, on the t5 its under 1" but on t56 flywheel its 1 1/2"