I build a 84 crete motor with vortec heads for a good friend and said he would pay me good to put it in for him. The body is a 1986 Camaro Z28. I pulled the 305 out and dropped the 350 in, he went back with the 700R trans. After looking at the 305 today, I have now noticed that the flywheels are different.
305 has 153 a tooth and the 350 has 168 a tooth. It is raining here and it is too wet for now to see if the converter will bolt up. I hope so,,, I'm guessing the starters won't interchange.

Are the flywheels different?

Will the converter bolt up?

OK!

Small 10.5" or so flywheels and flexplates use straight across bolt pattern starters and smalll bellhousings and such!!

Big, like 11"/12", use staggered starter bolt pattern starters and big, bellhousings and such.

pdq67

I was told to switch flywheels,,
Will the one piece\two piece rear seals matter?

14088551...305...86-87...2 bolt main...one-piece rear main seal

One piece versus two piece matters. Match up the starter to the flexplate versus pdq67. I d/k if your converter will bolt up or not, check the hole and see if they line up before putting everything together.

rain stopped and the trans will bolt up but the starter is differant,, plus the 86 153 tooth is externally balanced. Chevelle's have so much more room to work. Thanks

Hay guys

I have a 350 small block #3970010 and I need to get a flywheel for it for a 4 speed. Can you tell me if this would be a one or two piece seal, and if it is internal or external balance and what the diffrance is, and why ?

Thanks to all, this site is great.

Chris

That block is a 2 piece rear seal. ALL small block Chevrolets were internally balanced from the factory ACCEPT for the 400 and therefore flywheels and flexplates can be swapped from one to the next. Big blocks also use the same flywheels as the small blocks do ACCEPT for the 454 whice is externally balanced as well and take a dedicated flywheel of there own (I don't know much about the big block 348/409 engine so I can't say about those). 1 piece rear seal engines do take a differant flwheel/flexplate then 2 piece engines. Aftermarked flexplates can be purchased from the local parts store with dual bolt paterns to accept both size torque converters as well.Good luck with your build.

Chris,

Please read me again for the earlier 2-piece stuff!

Small, 10.5" stuff = straight-bolt starter and b/h and big, 11" stuff is staggered-bolt starter and b/h is all.

I am using OEM 11" type kit from Perfection Gear/ZOOM, (Summit), and a rebuilt starter on my car. Imho, darn GOOD value to me!!

pdq67

Actually the late model one piece main seal stuff is externally balanced.

And the old 348/409/427 "W" engines use neutral balance SB stuff.

Once had a hopped up 409 in my car! Sucker ran like a SB!!

pdq67