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Joined: Jul 2003
Posts: 20
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I've been re-reading 12 Port News, Sept/Oct 2003 - the "Cadillac" issue, and it got me thinking - AGAIN \:\)

I've come up with a couple of different combinations, and need my ideas confirmed or dispelled.

1. Using GMC rods with 194 pistons. 194 pistons use the same bore as the 235, and have the same pin offest. A pin height of 1.779" moves the piston down the bore, so the blocked must be decked. Reading old 12PN, I read that the block may be decked 0.150", so decking it 0.125" will return the piston to a stock deck height. The pin hole must be bored to allow the .990" GMC pin to be used.

Why use the 194 pistons/GMC rods in a 235"? Well out here in Australia 235's are common, whereas 261's are rarer than rocking horse sh*t!!!! I'd like to develop some more engine theories, and want to use the 235 to get them sorted on before I use a 261.

Are these pistons flat-tops? I've seen some stock bore examples on Ebay that are flat-tops, so I wonder if they all are. This setup will only work with flat-tops.

2. Using a 292 Late conn rod with original pistons instead of the Cadillac piston, adjusting the amount the crank is stroked for the difference in pin height when compared to the stock piston.

I have some oversized 261 Jahns pop-up pistons I'd like to use, and if I adjust the stroking of the crank to suit the 292 rods, I can get a whopping 302 C.I. out of a 261, be it boring it to an non-reuseable bore.

Thanks in advance for your thoughts


Mark (#1318)

Joined: Dec 2004
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sounds like it could work. you would have to put a dummy together and see if anything hits like rods hitting the block or cam. also check other rods you mite find one better then the gmc.


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