I'm still researching 455 builds, cams, etc, for when I get around to my 350-to-455 swap. One thing I can't find much info is this: At what point do the performance mods start to kill longevity, and mileage? For example, how much cam can you use before you start shortening the life of the engine? Or how big a cam can you use before you start killing off fuel "economy" (like Buicks were made for that anyway...:Brow: ) My situation is a more-or-less daily driver LeSabre that occasionally tows, where performance edges out mileage, and I'd like to see 100K++ miles before a major rebuild. I know there are a LOT of variables, but are there any "rules of thumb" out there? Any individual experiences to share?
build it right with the right parts, run good gas ect....and you can see over 100,000 on even a 500 h/p moter . even a stock 455 that isnt take care of and or over reved without being built to handle the rpm's will wear out fast or even throw a rod. you cant cut corners on a rebuild, buy all matching components for the way you want to set up your engine. just my 2 cents
The higher the RPM's, the faster the wear. Along with a lot of other factors....oil &...how often you change it....One could write a book on this subject...
After 100k of towing and the occasional track pull it'll probably be the maintenance items that kill the engine. There are a lot of good fixes that will preserve the engine in the sealing area. The new neoprene rear main and front seals are much better IMHO. Valve seals are better now, and with some oiling mods you can greatly improve the life. Performance-wise, I think it's mostly increasing cylinder pressure and temperature higher RPM's that increases wear. On a normally aspirated engine it's less of a concern IMO. To echo what Dan said, mainteance will mean more to the longevity than the parts. Regular oil changes, clean air filters, and good ignition componetns will reduce head and rotating assembly wear.
OK, so I change the oil at 3000 miles pretty religiously, I give it a few minutes to warm up the oil before starting out, I'm not rev-happy (I let the trans shift when it wants to), and I watch my gauges pretty closely. So, the concensus if that with proper maintenance, pretty much anything under the 500-hp should last as long/longer than stock, provided I follow the good rebuild practices found here on the board, yes? And I'm figuring that the 500-hp mark is about the limit of a true Street engine, as far as driveability, economy, etc. Is that about right? Thanks for the guidelines!
