Story is pretty simple; ex-wife needed simple and cheap transportation out of the four Volvo's we accumulated when we were married. Best candidate (AKA car I cared least about) was the 1990 16-valve sedan that wasn't being driven as the PO kinda made a mess of some things inside..... but I had been accumulating spares and whatnot for this motor, and she wasn't looking to spend the money to re-belt and re-seal this engine.... and, honestly, the selfish bugger that I am didn't want to part with the 16-valve motor.... which for some reason, I've developed a fondness for! So I figured, why not swap engine/trans/whatever between the 740's?

To 8-valve a 16-valve car is easy enough. Aside from the mechanical stuff, it's just a set of brains. Unfortunately, 16-valving an 8-valve 740 is supposed to be hard if the 8-valve is Regina. So.... I looked at wiring diagrams and cross referenced things, then thought who's to say I can't run a B234 with Regina? I know Regina is good for at least 160HP thanks to +T experiments on TurbpBricks. The seed was planted, it must be tried!

So I pulled the cars apart, labeling connectors, bagging stuff, and chucking it all into bins:




Every seal, gasket, and sealed surface got replaced or resealed in the B234. Balance shafts included. I even got new bearings for the balance shafts. Worth noting that every B234 part needed is available from Tasca. Rex flex plate went on the B234. The B234 was from a west coast car w/EGR, but a friend hooked me up with some non-EGR manifolds and brains.

Put it all into the wagon.





For the time being, I'm using the 8-valve intake with an out of production Yoshifab adapter. It makes a couple problems go away until the fall, and I was short on time due to moving across town.... of course, the B230 manifold is less than perfect: The throttle spool and throttle cable bracket touch the underside of the hood... so I beat the you-know-what out of them with pliers and a BFH. :-)

I'm still using the 8-valve exhaust too for the time being. Another cost saving measure. Most of these parts are almost new. Interesting fact: 8-valve and 16-valve head pipes are identical in fit. Diameter is all that's different. I guess the 16-valve down pipe is simply a regular 740 EGR pipe. The B234 and B230 exhaust manifolds have the outlet in the same position in "space" under the hood. Easy.






So, does it run? Yep! Pretty well, too. It'll pull all the way out to redline. I'm running premium, but always have. Still running the 3.73 rear end. Will swap the 4.10 in sometime in October when the house I'm moving into gets a cement floor for the garage. I'll get the B234 intake on it. Want to figure out how to keep Regina happy with the CSV. No provision for it on the B234 manifold... though I think later Regina deleted the CSV altogether. Will swap in the 16-valve throttle cable. Somehow, whatever holds it against the firewall got lost/broken when I pulled it out of the sedan.

Spring time might bring a proper exhaust, and perhaps kludging things enough to get the Bosch 16-valve brains to work.

-Ryan
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Athens, Ohio
1987 245, Dog-waggin'
1990 245 DL
1991 745 -- Will Regina run a B234F?