350 conversion flywheel info?

[peejcj8]

I have a Chevy 350 638 block that I had built with Vortec heads installed, I believe the 638 was used in 87-95 350's.

Im replacing an older pre-87 350 that is mounted to an 280 outdrive original to the boat, the one with the intermediate shaft in the bellhousing.

Boat is a 1979 albemarle

Will I need to change the flywheel?



Eric

 

[Don S]

Re: 350 conversion flywheel info?

Will the bellhousing fit over your present flywheel?

 

[RogersJetboat454]

Re: 350 conversion flywheel info?

I have a Chevy 350 638 block that I had built with Vortec heads installed, I believe the 638 was used in 87-95 350's.

Im replacing an older pre-87 350 that is mounted to an 280 outdrive original to the boat, the one with the intermediate shaft in the bellhousing.

Boat is a 1979 albemarle

Will I need to change the flywheel? Eric

If it's the original '79 block, and what you think you have for an approximate year on the new block is true, then you will most likely need a flywheel....

What's the casting numbers for both engines (the 638 tells me nothing)? It will be cast on the port side at the rear of the motor where the flywheel cover mates to the engine (the D shaped overhang over the flywheel).

 

[peejcj8]

Re: 350 conversion flywheel info?

I know it will fit in the bell since it is the one that came out, but not sure it will fit the crank. Im at work and about to make an order for freshwater cooling and was wondering if I should order a flywheel.

I suppose I could wait and remove the engine from the stand and see, I should have already done so.

Another question, the Dampener plate, Do they go bad? The one I removed from the old engine is quite rusty, should it be replaced?

Thanks in advance
Eric

 

[peejcj8]

Re: 350 conversion flywheel info?

If it's the original '79 block, and what you think you have for an approximate year on the new block is true, then you will most likely need a flywheel....

What's the casting numbers for both engines (the 638 tells me nothing)? It will be cast on the port side at the rear of the motor where the flywheel cover mates to the engine (the D shaped overhang over the flywheel).

Ill take a look when I get home and post.

 

[RogersJetboat454]

Re: 350 conversion flywheel info?

I know it will fit in the bell since it is the one that came out, but not sure it will fit the crank. Im at work and about to make an order for freshwater cooling and was wondering if I should order a flywheel.

I suppose I could wait and remove the engine from the stand and see, I should have already done so.

Another question, the Dampener plate, Do they go bad? The one I removed from the old engine is quite rusty, should it be replaced?

Thanks in advance
Eric

If you are talking about swapping the flywheel it's self, and the boat has the original '79 block, and the new engine is '87 or newer (as you believe) you won't be able to. The '79 is a 2 piece rear main seal which has a different flywheel than what would be found on a '86 or newer block with a 1 piece rear main seal.

 

[billbayliner]

Re: 350 conversion flywheel info?

Eric you are right..its not the block or the flywheel cover thats the problem it will be the crankshaft flange difference. up to 1986 and 1987 and later engines each use a different crankshaft flange. the early 2 pc seal crankshaft flange is not circular.. the later 1 pc main seal crankshaft flange is completely circular.
there are two flywheel tooth counts 153 and 168.
with the early 1979 flywheel cover you are limited to the 153 tooth flywheel.
the 153 tooth flywheel for the 1987 and later 1 pc main seal crank is a late Camero car application. check wtih chevy parts Michigan Motors has these too.


87 and later on left side...... 86 and earlier on right side.

2 pce crank has 3.58" pcd ( bolt circle) ;
1 pce crank has smaller 3.00" pcd

For cross reference
GM 153 tooth lightweight flywheel
2 pce GM # 14085720
1 pce GM # 14088646

 

[peejcj8]

Re: 350 conversion flywheel info?

Thanks for all the help guys. Bayliner, thanks for the pictures and the part numbers and years. Im buying my freshwater cooling and water pump from Michagan Motorz so i was very close to pulling the trigger on their 12 3/4 flywheel, but the 199.00 was giving me a hard time.

http://www.michiganmotorz.com/flywheel-1986-later-engines-12¾-diameter-p-154.html


I also took a quick look around the internet and Jegs has this http://www.jegs.com/p/JEGS/JEGS-Flywheels/1221208/10002/-1

which states that it is a replacement for the 14088646 and at 120.00 cheaper, I think that is a better option.

Eric