[grandam1979]

Do all 350 cranks have the smaller flywheel hub? I don’t know if you can get aftermarket flex-plate or flywheel for it?

[Bermuda Blue]

Originally Posted by grandam1979

Do all 350 cranks have the smaller flywheel hub? I don’t know if you can get aftermarket flex-plate or flywheel for it?

No. 350 and 400 cranks got the 2.6" hub around 76-77.

[grandam1979]

I think the 1969 350 I have out in the shop has a small hub? I will double check.

['ol Pinion head]

Originally Posted by grandam1979

I think the 1969 350 I have out in the shop has a small hub? I will double check.

If its a small register crank & in a '69 engine or even an early '76 production engine, it's been replaced with a late production crank. The small register 3.75 stroke 350 & 400 cranks began appearing in mid '76 production engines (455's stayed with 2.75" register). One thing I was able to somewhat watch for in the 90's & early 00's when had a engine core program going.

[grandam1979]

Originally Posted by 'ol Pinion head

If its a small register crank & in a '69 engine or even an early '76 production engine, it's been replaced with a late production crank. The small register 3.75 stroke 350 & 400 cranks began appearing in mid '76 production engines (455's stayed with 2.75" register). One thing I was able to somewhat watch for in the 90's & early 00's when had a engine core program going.

I checked your correct it is 2.75 the flex plate that came with it is smaller so not really off the 350. The interesting thing is this 350 looks to have never been apart but it has a early 68 crank in it 9793573 must have had some left to make it into a 69 engine it’s code YE and B269

[grandam1979]

After looking these parts over a little better this flex plate is only 2.360? V6 maybe? Crank bolt pattern is off also.

[Held for Ransom]

Originally Posted by 79 Phoenix

Well according to the chart it's definitely a 1971-74 crank with the 4813 #. There is no 79 or 80 casting mark on the front weight though to show whether it's a 350 or 400 crank. But it's definitely not a 400 block with bore size a little over 3 3/4"...

And judging by lots of normal wear on the bearings and the condition of the crank, it's been with this engine a long time... So, I would say it's a 1971 350 crank probably original to this block.

Next I will check the block #s to see what they tell me. Really appreciate everyone's help!

Although that's an OK chart, it's wrong. The 1969-70 cranks are cast 97954 and will have the 79 (350) or 80 (400) stamped on the front throw as confirmed by the full part number. I don't believe the '71-4 are stamped, but I maybe can check later as I have a '74 350 diassembled as they seem to have the same ending PN (....79/....80).

[79 Phoenix]

Originally Posted by Held for Ransom

Although that's an OK chart, it's wrong. The 1969-70 cranks are cast 97954 and will have the 79 (350) or 80 (400) stamped on the front throw as confirmed by the full part number. I don't believe the '71-4 are stamped, but I maybe can check later as I have a '74 350 diassembled as they seem to have the same ending PN (....79/....80).

Just checked more carefully but can't find a 79 or 80 stamped on front weight. Register is 2.75" though. Can't find a part# other than the 4813.

[79 Phoenix]

Originally Posted by 79 Phoenix

Thanks! You guys have been very helpful to me in figuring out what I have. I have a GT-37 with engine still in it. I have identified it as a 250 HP 350 w/manual transmission with numbers matching block with last 6 digits of vin on serial # on block.

You have helped me determine the other engine I have has a 71 crankshaft and I have now identified the block as a 71 250 HP 350 w/automatic trans.

Now I need to determine which one I will use.. If the numbers matching engine is not too badly worn out or damaged, I will probably rebuild that. Thanks again!

So, of the 2 engines I have, both are for 71 350 2bbl engines according to the block #s and crank #s. . One is designated for an automatic and has no pilot bearing in the crank and the other for a manual and does have a pilot bearing.

Is there any actual difference in the crank for an automatic and manual?

[steve25]

No, no difference .

When you check out your blocks for ware be sure to check the lifter bores for wobble.
Find the tightest fitting lifter and then use that one as your go no go in other bores.

[79 Phoenix]

Good to know...Thanks for the tip.