SIIA and III Chassis

[Dino]

What are the differences between the two?

[JSBriggs]

The biggest difference is the construction. The S2 is welded plate box construction, while the S3 is two stamped c channels welded together. There are minor changes for exhaust brackets, tank brackets etc.

-Jeff

[daveb]

mind you all the NAS series vehicles had welded plate box construction frames. it was only the s3 109s that started with the welded c-channel type. 88's were still welded box at least for the first few years.

series 3 also had a slightly different bellhousing crossmember to clear the clutch slave cylinder. i rebuilt my old s3 on a IIa frame and had to chop out part of the gusset on that crossmember for that reason.

aside from that, very minor differences mostly to do with the location of body mounting tabs. for the front of the rear tub they were in a different place and at some point between 72 and 74 they added two tabs in between the frame rails to help anchor the seat belts.

The biggest difference is the construction. The S2 is welded plate box construction, while the S3 is two stamped c channels welded together. There are minor changes for exhaust brackets, tank brackets etc.

-Jeff