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I've got a '77 GMC Motorhome fitted with the Olds 455 and a three-speed automatic Turbo-Hydramatic 425 (THM425)
Planning on removing everything off the block, while still on the vehicle, to replace old worn out parts and hoses. Replace all the seals and gaskets that I can. Instal new timing chain. Paint block and brackets. Also, going to remove intake and block off middle exhaust ports. Make it look pretty for a clean environment for future repairs and diagnostics.
At the moment it runs fairly good. It's all stock from what I can tell but covered in years of grease and grime.
Looking forward to talking with you and gaining much appreciated knowledge.
Be aware that while replacing the timing set is a smart thing to do, it won't be easy. In addition to the usual problem with reinstalling the front cover on an Olds motor with the oil pan in place, the MH uses the Toro front motor mount bracket that bolts over the front cover. That means you'll have to support the drivetrain so you can remove that bracket and cover. Not impossible, but just be aware of the issue.
Hey Joe. Yea, that's the biggest issue. I've owned it for 5 yrs and all the while been on the sites dedicated to this beast. Lots of folks have well documented doing this. I bit tricky, but not impossible.
