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Discussion Starter · #1 ·
the flexplates between the l67 and l38 are different mounting depth for the converter. Due to different counterweight differences i need to use the l67...can I just use spacers and longer grade 8 bolts?

Source: I've built multiple hybrids of Series 2&3 engines for myself and others, because I understand the universal application of airways and bolt patterns, etc. between them. We favor Series 3 engines
Dave, I read your comment on another post and it sounds like you may have dealt with this problem? Here is the full story...

I bought a 98 camaro 3.8 auto which had coolant in the oil and spun a rod. I researched the series 2 and 3 na's and read that the longblock was the same, and since there was a 2009 buick with 80k miles recently brought in at my local pickapart with a side impact...I figured this was a perfect donor.

I swapped pan/pickup, intake, exhaust manifolds, etc from the series 2 onto the series 3 front wheel drive block...all holes were present and threaded, that was great! Then I went to install the flexplate. Holes were off slightly. I searched many sites and finally ran across a thread which explained that the rods and pistons were heavier on the series 3...so that flexplate must be used due to a different balance. I had kept the harmonic balancer/pulley as well. I put the series 3 flexplate on and it bolted right up (of course, since it was off the engine in the 1st place). I bolted the trans on and thats where my problem became known. There was about a 1/2" gap between the flexplate and converter. I took the trans off and compared the two - sure enough the series 2 is about flush with the outer part of the ring gear. The series 3 is flush with the ring gear on the inside. And yes, it is installed the correct way.

Thanks in advance!

Heath
 

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The series 2 and Series 3 front wheel drive flex plates are the same the only issue comes into the rear wheel drive cars.

The pattern at the crankshaft is the same between the two.

Two of the holes are slightly misaligned on our crankshafts to flaxplate this makes sure that people cannot install the flex plate with the balancing counterweight in the wrong clock position.
 

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Discussion Starter · #3 ·
So what can be used in a RWD car that has a series 3 swapped in place of a series 2? Using the series 2 balancer fits, bolts up, etc...but the balance is way off and the vibration will bounce you out of the car.
 

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Where did this idea come from? It's odd that my '06 Series 3 engine with my '98 Series 2 balancer has been happy since 2007, as has any other I've done conversions on since then. These engines are not that different between those generations, and even shared many items during the crossover years (some early S3's in 04-05 were just S2 blocks with new top-side parts).
 
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