Hi guys, like many I will soon have to make a decision, have my 350 rebuilt (68 skylark) or swap for a 455. In both cases, I would not go for aluminum heads, just a moderately above stock build. I can take in and out an engine from the engine bay but not do any assembly. THE question actually is "approximately how much more expensive is it to do the swap compared to keeping the 350".
The two wild cards in question are: 1. the condition of your 350 2. the condition of the 455 you buy If you have to rebuild either then that’s the option that will cost more. to swap to the 455 all you really need are: coil springs, frame pads, fan shroud, otherwise it’s a bolt in swap.
Don’t forget modifications to transmission/ ungraded transmission to hold up to the 455 with new torque converter, rear end work(gears ,posi, control arm/traction devices.) rebuild will be alitttle more for the 455 in parts. But make more torque. accelerator cable should be replaced for 455. You will probably end up getting a bigger radiator. You will need modifications to exhaust for 455. you will spend more on the 455 since it’s not originally a 455 car. Trans and rear end will need upgrades.
I already have an 8.5 ''corporate'' rear end that is much stronger than the regular 8.5 with new 3.42 gears and a new posi in it. Transmission is a TH375 so stronger than th350, but not sure when the last rebuild was done. I know it will be more $$$ for the 455 but what are we talking about? 5k or 1k more ? Thanks!
If you can find a 455 that runs well and doesn’t need a rebuild then it’s easy then it’s low cost. It’s easier to replace the frame pads with the front springs removed too.
68 would have had a 300 Transmission not a 350, which a 350 would be decent behind a 455 vs the 300. Depending on what you buy in aftermarket parts, probably closer to 1000 if you keep more of the stock parts.
He has the TH-375 which is basically a Th-400 with a 350 output shaft. No need to touch it if it works well.
depends on how much PERFORMANCE you want a 455 is much stronger in stock obviously and you can get deals like thi shere in my area https://dallas.craigslist.org/dal/pts/d/terrell-buick-455-engine/7128357348.html add some mounting hardware from rock auto and you have a BBB setup easy
IMHO, the biggest difference you'll "FEEL" between the 350 and 455 is the torque, and that torque is what you drive. You can build a strong 350 and achieve the HORSEPOWER output of a stock Stage 1 455, BUT, you'll never approach the sheer torque output of a 455, and there again, its the torque you feel The 350 Buick is no slouch in low end torque in the small block world tho, but there again, apples to apples, the 455 NA and the 350 NA (Naturally Aspirated) the 455 would win in the torque race. If you boost the 350, then it will exceed the torque of the 455. If you boost the 455, then were back to apples to apples, the 455 would win. BUT, the 350 is a much stouter block than the 455, so boost is a very viable option
I’ve thought about this conundrum for the last 10 years & unfortunately both ways are costly. Finding a running 455 is getting harder & cost is getting higher when you do find one so that has to be taken into consideration. A rebuild for the 455 or 350 isn’t cheap if you pay an engine rebuilder/machinist but then at least you know what you have when it’s done. Also, there isn’t a simple bolt on boost set up or kit that I’m aware of for any Buick motor so while it’s possible it isn’t as easy as say an LS1 build, again you pay the premium for owning a Buick. I’ve wrestled with it both ways & haven’t found the deal when I’ve had the cash, someday hopefully.
I have been thinking this also. I would love to drop a 455 in the wagon. I am poor so it will take sometime to get it even ready to drop in. Yet the 350 in the wagon runs great. I would look at Aluminum heads for the 455. But now I can get a set for the 350. get a nice cam, the single plane intake and a Fi-tech EFI and I am golden. Tim
Having built and maintained near identical cars, one exclusively with SBB engines and one with the 455 I may be in a position to comment. The 455 car (a '69 MGB-GT hardtop) is just a pleasure to drive It has what feels like bottomless power and everything is just effortless with that car. Yes it does have a little more weight in the front but by the time you figure in the alloy heads and the blower on the SBB, not all that much. The biggest difference is that the GT is geared for the highway and has a stock rpm range. Which is well suited to just about anything you might want to do with the car, from idling in a parade to a high speed cross country run. The blower car (a '71 MGB Roadster convertible) is a completely different animal. It probably does make slightly more power than the GT and it is geared differently so that power is more immediate. But I've changed the gearing on both cars and they have both run with 3.45 gears. The small block car just feels peppier. I'd say as a result mainly of the lighter rotating assembly and the blower, whereas the 455 car just feels like it has an abundance of lazy endless power. Both are very fine but just different, and both run pretty mild cams. Interestingly, the cost to build and the effort to install was very similar in both cases. The SBB has a blower but the 455 has TA Street Eliminator heads. Both still have plenty of overhead left for power upgrades and both are relatively understressed. So my take on it is that you should consider the desired character of the car you want to build. Think in terms of the one having massive elephantine power and the other being more of a thoroughbred. Then go with whichever one appeals to you more. There's a reason they put the BBB in those land yachts. Jim
