Hey out there, first time 66 skylark owner and computer owner. Need advice on swapping a 300 for a 340, worth it or not???
Let me first congratulate you on a wise purchase! 66 is where it is at! It is a very easy swap and if you already have the 340 and it is in good shape I'd say go ahead and do it. If you are staying true (or as true as possible) to the year of the car the 340 is a no brainer. However, there are a handful of us here that like the 350 (me being one) Here's some info for you regarding the 340 and including the 350. Excellent parts for both can be found at TA performance. http://www.taperformance.com/ 340 The 340 cu in (5.6 L) 340 was a stroked (to 3.85 in (98 mm)) version of the 300. It had a two- or four-barrel carburetor, the two-barrel with compression of 9 to 1 comp. ratio rated at 220 hp (160 kW) at 4000 rpm and 340 lbft (460 Nm) at 2400 rpm, and the four barrel with 10.25 to 1 comp ratio, rated at 260 hp (190 kW) @ 4000 rpm and 365 lbft (495 Nm) @ 2800 rpm. It replaced the four-barrel 300 for 1966. It was produced only in 1966 and 1967, with the new Buick 350 taking its place after that. [edit] 350 Buick adopted the popular 350 cu in (5.7 L) size with their final family of V8s. Although sharing the displacement of the Chevrolet Small-Block engine family, the Buicks were substantially different. The Buick 350 V8 had a 3.80 in (97 mm) bore (like the 231) and retained the 3.85 in (98 mm) stroke of the 340. It was introduced in 1968 and produced through 1980. Its nickname is "Dauntless." The major differences of the Buick 350 when compared to other GM V8's are deep skirt block construction, higher nickel-content cast iron, external oil pump, under square bore sizing, 3 in (76 mm) crank main journals, and 6.385 in (162.2 mm) connecting rods. It is an extremely rugged and durable engine<sup class="Template-Fact" title="This claim needs references to reliable sources from March 2010" style="white-space: nowrap;">[citation needed]</sup>, and some of the design characteristics of the Buick 350 are found in other Buick-designed GM engines such as the 231 V6, and Series I, II, and III 3800 V6's. Of all the GM 350-cubic-inch (5.7 L) engines, the Buick 350 has the longest stroke. It made the Buick 350 significantly wider than the other GM 350's — essentially the same width as the Buick big-blocks, which have the shortest stroke of the GM big-blocks. In fact, at a glance the Buick 350 is commonly mistaken for the 455 engine due to the oversized intake manifold atop the engine. The Buick 350 also shares an integrated aluminum timing cover as do most of the Buick small and big blocks which incorporates the oil pump mechanisms as well, leaving the oil filter exposed to oncoming air for added cooling. The Buick 350 was used in the Jeep Gladiator and Wagoneer from 1968-1971. When you get enough posts insert a picture or two. Scott
Thanks, great info, I have both engines and they both seem to run fine the 340 has 91,000 and the 300 has 70,000. I'm trying spend as little cash as I have to at this point so buying another engine would have to wait. Both engines have oil leaks at various places with 91,000 could I get by with new gaskets, or should I do more?
New gaskets should cure your oil leaks. Where abouts are the leaks? And where are you located? Tell us a bit about yourself and your car and you'll find a significant amount of good information and parts on this site. Scott
Most of the oil seems to be coming from front and rear of the intake, lots of oil and dirt around the front of oil pan, front and rear. I don't think it is serious no drips just seems to be seeping. I've one car for awhile now and got the other one a few months ago. Neither engines smoke or make strange noises. Just looking for a little more power.
Oh, eastern kentucky, 44 years old, been into bikes all my life, recent knee injury put an end to going fast on motorcycles , getting old stinks. Wanted a car forever decided on buick because different but cool.
Both engines have oil leaks at various places you should be able to get neoprene seals to replace the rope gaskets at the front and rear main positions. Its nickname is "Dauntless." specifically, that's the nickname for Buick 350s that were placed in Jeeps by Kaiser back in the late 60s / early 70s. i don't think Buick ever used this nomenclature. "Dauntless" also referred to the 225 v6 from Buick that Jeep used for even longer. http://jeeptech.com/engine/dauntless225.html http://www.jeeptech.com/engine/dauntless350.html
Need advice on swapping a 300 for a 340, worth it or not?? that's a 13% increase in displacement. hard to turn that down. otoh, the Buick 350 OR 1980s turbo v6 would both be near drop in substitutions. t-6 would probably give you the most tire spin. :laugh:
Well we have a lot in common except the bikes....wife didn't want me to have one and bought me the buick instead. (I had one when we were dating in college and sold it in college too. Wish I still had it) I've got a year on you and know getting old stinks. Had alot more energy BK (before kids). Anyhow I'll try to help as much as possible as will most of the guys on here. Try degreasing the engine first and then monitor the oil leaks. If you decide on using the 340 and it is out of the car...life will be much easier to change the gaskets. Check out the Teambuick site too as they have a few online manuals you will need. Scott
I agree on the displacement, seems like a no brainer. Any suggestions are where to get parts? I went the local Advance for a upper radiator hose for the 340 and the kid looked at me like I had ask for a ostrich egg.
Great to know Scott, man forgive me for being so slow replying, I have no idea what I'm doing on this computer.
Great to know Scott, man forgive me for being so slow replying, I have no idea what I'm doing on this computer.
I like rockauto.com - you can put the year, make, model, etc in and search through to get what you're looking for.
I would normaly say buick 350 as they're easier to find and more cubes... but if you want headers and a 350...you'd have to modify/re-oute a tube or two for it to work in a 66/67. That being said, the 300/340 has shorty headers available from sanderson? (think that's the company) so, no issues there! TA is comming out with AL rover heads! which will bolt to youre 300/340 blocks ta performance also has the typical bolt-ons along with internal parts and gaskets..so they prettymuch got you covered on just about everything you need. rockauto is a good site as mentioned.. turbo 3.8 or 4.1 engine(lc2) would be an awsome swap with a 200r4 for best out the box power and mpgs! but a lil but more involved aling with more $$$ since you dont have any of those to start with. all in all, weather it be a fuel injected turbo 6, buick 300, 340 or 350 they're all great engines! you can always slap in the 300 as it has less miles then build up the 340 when the 300 craps out! :beer
Exactly what he and nothingface5384 said. I just got header flanges and will have shorty headers made. If you really want to throw the guy at advance auto for a loop ask for a dwell meter....:laugh::laugh::laugh::laugh: rockauto is a very good site and if you want to get performance parts the previous post citing TAperformace is the buick performace leader to date. :Smarty: don't fear the computer! Scott
Great info, going to check them all out. I'll try and get some pics up as soon as I can. The 300 is already in the the car I'll be keeping, probably will run it while working the 340 over. I'm figuring the trans and rear will handle anything the 340 can give it? Thanks again for the help, more info in 10 minutes than I've gotten in 6 months!
hey no problem! and if the 300 is already in the car run it till it dies and swap the built 340 in:TU: yea, both trans and rear will handle the abuse. current trans is an st300(2spd auto)(not sure if it has the switch pitch feature though) current rear should be an 8.2 either either craps out th350(3 spd auto) is a direct bolt in no mods at all 200r4 wont be much more work, just have to get the right rear gears.. 71-72 buick skylark/71-72 olds cutass has the rear you;d want to replace with if the lil 8.2 gernades or you can just buy a brand spanking new 12bolt with 9in bolt in axle ends through scandc.com lol
