4L60E Flex Plate

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jce98

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I would not have expected a problem with bolt circles. So far as I knew, the 700/4L60/4l60E torque converter bolt circles were all the same, and the same as the TH350/TH400 except with metric threads instead of SAE.

So this is all-new to me.

Does the "new" engine have a one-piece rear main seal, or the old 2-piece rear main? Seems to me that the ancient Powerglide torque converter bolt pattern was different from the 350/400/700/4L60/E, but it's been so long since I've even seen a Potatoglide that I'm not sure any more. Point is, there's no Potatoglide flexplates for a one-piece-seal block unless they're made in the aftermarket, which seems unlikely for thieves to use.

OTOH, I can see them slamming in an old 283/307/327 that they found in the back of someone's garage during a previous thieving session. Heck, I had a '69 Impala with a 350/Glide, until I pulled the 'glide and stuffed a TH400 in place.


Probably. And it would be nice to know, but not critical. If the decks of that block have been planed, those numbers are gone anyway.

I'd be more interested in the block casting numbers, which may be on the block below the exhaust manifolds. Potentially on the bellhousing area, visible from above at the rear of the engine.

But what really matters is the torque converter and the flexplate; and block numbers won't tell you that.


NO.


Lean AWAY from the Dremel and carbide bit.
088 is stamped on the block by the block drain on the driver side. One piece rear main. Going with a new flexplate, just trying to figure out which one is needed. At this point I am going to get serious about tracking down the numbers. Plus clean up a few things. Thieves steam cleaned the firewall before swapping engines, nice of em.
 

jce98

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My guess is that the wrong flex plate is in there. In a similar circumstance, I had the GM crate 4L70E put in behind the new Vortec 383. The stock 168(?) tooth FP couldn't be used, and I had to get a 153 tooth. Other issues rose their ugly heads for me, but that's a different animal altogether.
Could you check the part number? I think your problem is the reverse of the one I had. It's something to look into anyway.

Here's a page from my thread.

Good info. Looking at your pics, your TQ holes are off towards the teeth. Mine is opposite, TQ holes are off towards the center, bout an 1/8th.
 

east302

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088 is stamped on the block by the block drain on the driver side. One piece rear main. Going with a new flexplate, just trying to figure out which one is needed. At this point I am going to get serious about tracking down the numbers. Plus clean up a few things. Thieves steam cleaned the firewall before swapping engines, nice of em.
880 is a 350. Either the sawtooth or single triangle on the head will be vortec. Usually they match but some aftermarket rebuilders interchange them.

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Schurkey

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Fixed that for you.
Actually...no.

Before we knew it was an 880 block, my concern was that they poked some ancient engine that had been in front of a Powerglide...with the potentially incompatible flexplate thereto.

But now that we know it's an actual 350/one piece seal block; the flexplate becomes something of a mystery. Certainly, I'm not familiar with what's going on.
 

jce98

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Actually...no.

Before we knew it was an 880 block, my concern was that they poked some ancient engine that had been in front of a Powerglide...with the potentially incompatible flexplate thereto.

But now that we know it's an actual 350/one piece seal block; the flexplate becomes something of a mystery. Certainly, I'm not familiar with what's going on.
I'm thinking I have a 4l80 flexplate on the mystery engine, trying to bolt to 4L60 TQ. In the assortment of parts, there are two sets of air intakes. The factory one and then another factory GM air canister/intake that looks like it may have come off of a 2500 van or truck? That being the case it would have the 4L80 flexplate. One thing for certain, no 2 sp Powerslide. Pulled a few of those in my younger days.
 

jce98

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880 is a 350. Either the sawtooth or single triangle on the head will be vortec. Usually they match but some aftermarket rebuilders interchange them.

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I have the triangle heads. Anxious to get it rolling and tuned. Little things I noticed, my plug wire looms were brittle and several missing. The wire looms on this one are in tact. Holes on the distributor for the cap on mine were stripped, as most are. I replaced the cap, and the screws tightened up perfect.
 
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