Technical MOTOR, Dang! The secret is out...BUICK 350 engines!

This one is for C9 and the maybe three other folks here who already know about the unsung lightweight hero of the smog motor era...the Buick 350. (And for others who are interested, naturally!).

Available from 1968 to 1980 in various Buick models, the 350 engine (or 'small block' as many call it) was a modern, overhead valve engine designed to replace the nailhead as the company's base V8 engine. The factory produced both two and four barrel versions of this engine, and it was also loaned out to AMC for use in some of it's Jeep models.

Looking much like it's bigger 455 brother, the 350 Buick can be quickly separated from it's Pontiac and Oldsmobile 350 cousins by noting that the distributor is in the front of the engine at an angle. Cylinder numbering is the same as a small block Chevy with odd numbered cylinders on the left (driver's side) bank and evens on the right (passenger's side) bank. Firing order is the standard 1-8-4-3-6-5-7-2 for the Buick 350 and the distributor rotates in a clockwise direction.

The odd thing about the Buick 350 is that it is nearly a perfect 'square' engine, featuring a 3.800" bore and a 3.850" stroke from the factory. This gives the engine a nice, flat torque curve, but hampers any screaming, high rpm dreams you may have had for this particular mill! Still, it is a great performer if built to the conservative side, allowing it to take full advantage of it's natural low and mid-range capabilities.

Other specs for this engine include a main journal diameter of 2.9995" and a rod journal size of 2.0000" with between .0004" and .0015" clearance called for on the mains and .0002" and .0023" on the rods. End play should fall between .003" and .009" on the crank, with thrust on #3.

These engines were a product of the smog era, and as such, they saw compression drops throughout the 70s. They held at 8.5:1 up until 1975, when factory specs dropped to 8.0:1 for the remaining span of the engine's production. This makes them excellent performers on low octane pump gas, and works well for a daily driver, but to wring any serious performance out of them will require a piston swap or some minor cutting on the decks or cylinder heads to acheive a more robust, yet still streetable compression ratio of around 9.0:1 or 9.5:1. Any more than that is really too much for a street engine relying on questionable quality fuel from random service stations!!

Crane Cams offers several hydraulic grinds, and one solid lifter grind for the Buick 350 engine. Here are the part numbers and specs, starting from mildest and working up from there.

Part # 710511
Duration @ .050 = 194 I/202 E
Advertised Duration = 252 I/260 E
Lobe Separation = 112
Gross Lift = .400 I/.416 E

Part # 710531
Duration @ .050 = 202 I/210 E
Advertised Duration = 260 I/268 E
Lobe Separartion = 112
Gross Lift = .416 I/.432 E

Part # 710571
Duration @ .050 = 218 I/226 E
Advertised Duration = 276 I/284 E
Lobe Separation = 112
Gross Lift = .448 I/.464 E

Part # 710631
Duration @ .050 = 226 I/234 E
Advertised Duration = 284 I/292 E
Lobe Separation = 110
Gross Lift = .464 I/.480 E

Part # 711161 (solid)
Duration @ .050 = 238
Advertised Duration = 304
Lobe Separartion = 108
Lash (hot) = .022
Gross Lift = .512

Note that the solid lifter cam is a 'square pattern' grind. Solid cams can be 'tuned' somewhat by experimenting with different valve lashes within a given range, so that this cam can be effectively run as a dual pattern cam to some degree with slight changes in the lash setting between the intake and exhaust valves. Not really an issue, as I doubt that anyone who isn't trying to build an all-out racing version of the Buick 350 would go down this road!

I used an earlier version of the 710571 hydraulic grind in my ex-wife's 350 engine and it worked out well with the stock intake, a Carter AFB, recurved HEI distributor and dual exhaust. It had a nice lope to it and really came on strong in the 2200-5000rpm range...making her old sled get up and boogie, much to her delight!

(The lopey idle also attracted curious glances from guys driving musclecars and hot rods!)

Swapping in a performance cam is just as simple on a 350 Buick engine as it is on nearly any other. There are some funky nylon rocker arm retainers that you will have to pop out with a screwdriver to pull the rockers off, however. I was able to re-use mine, but they DO become brittle with age and should be replaced if they crack or look suspect. Just something to be mindfull of.

The stock 4v factory intake works okay on a street engine tailored for mild performance useage, but it is a heavy cast iron sumbitch! The best game in town by FAR is the 350 Stage 1 aluminum dual plane intake manifold available from TA Performance for the Buick 350. It works well up to 7200 rpm, which is more than most semi-stockers will see. (455 intakes will NOT fit a 350, by the way!). TA Performance also offers several performance cam grinds for the underdog Buick motor, and they are currently the leader in supplying parts and knowledge for these engines.

Check out TA Performance at :

http://www.taperformance.com/

Headers for a rod or custom application are likely going to fall to something home-built starting with a flange made from an exhaust manifold gasket...but the 68-72 Skylark manifolds work okay for a mild application. (That's what I used on my ex's car...a buddy had dropped a 455 into his 71 Skylark, and I got the old 350 manifolds for free!).

Yes, the Buick 350 is a rather obscure oddity...but that's part of it's charm! If you're looking for a cheap, lightweight powerplant to move your project down the road, you may want to consider one of these long stroke small blocks! Manual and automatic trannys will work, and any B-O-P pattern TH350 or TH400 will work with your favorite converter, shift kit, etc. I know manual transmissions were available behind the 350 Buick in Jeep applications at least, so with a little parts scrounging, you can run a stick shift behind one of these engines.

(I seem to recall a friend's neighbor owning an early 70s Buick Apollo with a 350 and a 'three on the tree'...but I can't be sure now...that was well over 20 years ago!)

So...the 'secret' is out!! Buick 350 "small block" engines make interesting alternatives to the more common fodder, and offer decent performance in a reliable and lightweight package with the distributor up front to make firewall issues simpler for anyone considering a swap.

 

hmm any cool valve covers made for em?

 

Good summary of the Buick 350 Fat Hack. I think the biggest advantages to the Buick is the light weight and the front distributor. Buick 455 has the same advantages in a bigger package. The fact that the 350 has great torque is a surprise to many.

Like you said, TA Performance is the place to shop for parts, they are a Buick specialty house.

You can not just swap a Buick 455 for a Buick 350 without changing frame pads and engine mounts, but otherwise it is an easy swap.

One thing to check on the Buicks is the front cam bearing. They have oil passages that must be lined up with holes in the bearing, in fact TA and others have a grooved bearing to help with the oiling issues. This is probably the weak link of Buicks, they tend to eat this bearing if not installed properly. Make sure your machine shop is aware of the specifics for your engine type, if it is not a SBC or SBF belly button engine.

 

I think Kenne Belle offers valve covers for 'em, Psycho-D...otherwise, you gotta chrome the stockers!

Good points, 38Chevy....my one high school buddy and his dad owned several 1970-72 Skylarks and GS Buicks, and they did the 350 to 455 swap fairly often, although one of their cars had a pretty stout 350 in it until a 455 took it's place!

There are also two water pump bolts that go into the water passages that should get a thread sealer of some type on a Buick 350. If looking at the pump straight on from the front, the bolt furthest to your right and the one just below and to the left of it are the ones you'll want to seal to prevent coolant from trickling out of the engine or into the oil through the timing cover.

 

How about overall engine length? And longblock weight? That's some helpful info for anyone considering using one.

 

I had a chart that my old shop teacher copied from the pages of HOT ROD magaizne circa late 70s or early 80s that had the external dimensions and weights of all the domestic engines at the time. Really good info, but I can't find it just now. I will post the infor (the whole cart for that matter!) as soon as I can locate it!

(The chart also gave starter locations and such...GREAT stuff for swappers!)

But, I do remember that Buick 350s and small block Fords were the lightest of the modern V8s...along with the weakened Pontiac 267/301 duds!

 

Aha! Found this very cool chart online:

http://www.westechperformance.com/pages/Tech_Library/Popular_Engine_Specs/dimensions.html

Buick 350 is 30" long X 28.5" high X 25.5" wide according to the chart.

Rear sump, right side starter location.

Weight on the Buick 350 is 450 lbs.

(Sorry for leaving this info out earlier...my goof!)

 

summit racing has that same dimension info on their website i think.

a few years back, Classic trucks ran some pull out specials with the same info.

they also had one for automatic tranny ID.

 

thanks for the info fat hack. sounds like somthing else to look for when i'm out junk yardin'. i've been thinking about a cad swap for the merc. but this buick might be a better choice. dose buick have their own bell housing bolt patteren or is it shared with something else? i guess a mid 80's unibell would work ( i'm thinking 700r4).

 

The Buick 350 uses the standard B-O-P bellhousing pattern, making tranny choices easy!

 

Thanks Fathack.
Gotta confess though, me no speak no good sometimes....

I shoulda said 455 Buick.
Far as me and the Buick Brothers go - all both of them - we figure there's Nailheads and 455's.
Now they won't even talk to me....

Kenne-Bell makes cast aluminum rocker covers for the big Buicks.
This style available in as-cast or wrinkle black with aluminum accents as shown.

TA also makes rocker covers.
Their design a little more rounded looking, but still cool.
Got a pair of those for the other engine.
They're available in as-cast, polished and I think with black wrinkle paint and aluminum accents similar to the KB covers.

 

Fat Hack - thanks again on the enlightenment.

The one thing that i like is the dizzy is on the front of the motor so that opens up some more firewall options.

The 200R4 was a real popular B-O-P tranny with about the same dimensions as a T350, I wouldnt put too much horse ahead of one without doing a decent build on it first.

Later Brian

 

[ QUOTE ]
The Buick 350 uses the standard B-O-P bellhousing pattern, making tranny choices easy!

[/ QUOTE ]

But you've got to find a Jeep with one if you want to run a stickshift? What about the crankshaft- is there a pilot bearing hole or would you need a Jeep crank, too?

 

One thing to watch out for is the water pump casting. I saw a few of these where the casting was too worn out for the pump impellers to seat. Wouldn't cool for love nor money. Other than that, they're a great engine that respond real well even to switching from single to a low restriction dual exhaust.

 

[ QUOTE ]
[ QUOTE ]
The Buick 350 uses the standard B-O-P bellhousing pattern, making tranny choices easy!

[/ QUOTE ]

But you've got to find a Jeep with one if you want to run a stickshift? What about the crankshaft- is there a pilot bearing hole or would you need a Jeep crank, too?

[/ QUOTE ]

Does anybody know more about Buick trannies? I've got a '70 Jeep Wagoneer with the Buick 350 and a TH400 behind it. I've been told that the tranny is actually a nailhead pattern with an adapter ring. I do know that there's a ring there, but I don't know about the nailhead part.

I've got a 455 that I'm planning to swap in there, and I was wondering if it would be better to find a BOP tranny to use and save my other for a 401 I've spied for cheap. What tranny options are there with the nailhead?

Sorry to hi-jack, Fat Hack. I'll throw in info on Poston in the hopes of forgiveness. They have lots of goodies for the Buicks as well.

Poston Buick Website

 

Maybe not the motor for me, but this is a killer example of what should be on the HAMB!

Thanks!

Mike

 

Don't those things have a kinda weak oil pump setup? Seems like I remember them being like an AMC, with the oil pump cast as part of the timing cover?

 

I remember having a 69 Century 350 "loaner" from a buddy that got up and really suprised me. My regular commuter beater (64 Falcon with a warm 302/C4) needed to disappear for a few weeks after outrunning a MA Registry cop and that 4dr was the perfect cover. This was around 76. After changing colors the Falcon was back on the road, that cop was around for almost a month every morning looking for me!

Always wondered why that engine never got popular, it sure moved nice from a dead stop.

 

BUICK 350 FRONT COVER NOTES:

The Buick 350 usues a big aluminum timing cover which houses the water pump and the oil pump. This casting has a few little qualities of it's own that you might want to be aware of before messing around with one.

First, as mentioned a few replies ago, there are two water pump bolts that pass into the water jacket. Thread sealer should be used on those two bolts at least, to prevent coolant from leaking out of the engine, or into the oil through the timing cover. If looking at the water pump straight on from the front, the bolt furthest to your right, and the one below and to the left of it are the ones to watch here.

Gasket catalogs still list a rope seal for the the timing cover on 350 Buicks, but a Turbo V6 Buick neoprene seal is a direct replacement that works FAR better, and should be on your parts list if your diving into one of these mills. My old machine shop guy turned me onto this trick when I was building the 350 Bucik for my ex-wife's car.

The oil pump can be upgraded to high volume status simply by purchasing a TRW hi-volume rebuild kit for it. It comes with the parts you need to rebuild your oil pump and will increase oil flow. Simply ask your parts counterman for the hi-volume rebuild kit.

Be sure that you check your timing cover over very thoroughly before prepping it for re-installation. They have been known to crack, shift or simply wear out in key areas...causing mystery fluid leaks and other untold headaches! Give your cover a close visual inspection, checking the gasket surfaces for squareness and all areas for evidence of excessive porousity. Seek out a new cover if you have any doubts.

The aluminum timing covers on these engines can wreak havock on some of the bolts that enter or pass through it. Over time, and with exposure to the forces of nature, and heating and cooling cycles, those steel bolts can seize up and break off in the cover, or cause the cover to break when torque is applied to break the bolts loose. I had to have two broken bolts removed from my timing cover after pulling the engine apart! Be aware of this when disassembling your engine, and use an anti-seize compound during re-assembly to prevent such problems in the future.

When rebuilding your oil pump, cleanliness is the key, as well as being on the lookout for excessive clearances. The gears shouldn't wobble or rattle around like crazy when test-fit prior to final assembly. Pack the pump with petroleum jelly and assemble. Tourque the oil pump cover bolts to 10 ft/lbs and you're ready to go!

Buying a new water pump is a common sense move, and something I always do with a fresh motor or when swapping a cam or installing a new timing set into an existing engine. Nothing special to watch out for here...install the pump with your favorite sealer on the gasket and use thread sealant on the two bolts mentioned previously.

Just a few pointers to help you with a potential problem area on an otherwise excellent engine!

 

I found a chart showing engine weights, and indeed the Buick 350 IS a lightweight motor...450 pounds, just as I remembered it being!

(By contrast, a small Chevy is 575 pounds).

Check out this site:

http://www.team.net/sol/tech/engine.html

 

After poking around, I'v e found references to a three speed manual transmission being offered as the base tranny choice in some Buick models with the 350 engine, so factory flywheels ARE available, but may prove hard to find, since the vast majority of Buicks came equipped with automatic transmissions.

I'm thinking an Olds or Pontiac bellhousing would work, and that would allow use of any GM manual transmission...such as a Saginaw, Muncie or T-10 behind the torquey 350 Buick mill if a flywheel could be scrounged up.

Something to be on the lookout for while crawling through junkyards...that old 1968 LeSabre just might have a three speed behind it's 350 two barrel!!!

 

The problem I have found with those integral timing cover/oil pump setups is that the pump cavity tends to wear out, meaning the timing cover is junk.Finding a good used timing cover is sometimes difficult. That's a big problem on the AMC's, anyway.

 

Here's a Jeep site which indicates that the Buick 350 was used in J-series pickups and Wagoneers from 1968-1970. It shows compression at 9:1, which it was until 1971 when GM dropped it to 8.5:1, then it fell again in 1975 to 8:1.

http://www.jeeptech.com/engine/dauntless350.html

I drove a 69 Wagoneer with a 350 Buick and a manual tranny, and it was gutsy sumbitch for a big old hulking 4x4. It was a used rig some kids downriver had up for sale and I took it for a test ride. Shoulda bought it, in hindsight...only $300 and I turned it down to buy a Roadrunner for $400...decisions, decisions!!

 

Here is another little "secret I thought of for those Buick 350's. Let's say you have a car with the Buick 321 V-6, such as the 80's GM G-bodies (Cutlass, Regal, Monte Carlo, etc.). You can swap a Buick 350 right in there by using the 231 mounts. Same trans and all. Easy swap and makes a nice powerful cruiser. Some of these cars came with Olds 307 engines, you can bolt an Olds 350/403/455 in them just as easy.

Another easy swap is the older 60's Buicks with the 300/340 engines. You can swap them out for a 350 as well. The 231 V-6 is essentially a 300 with 2 cylinders cut off.

 

FH, I have a 76 Buick 350 that I plan to rebuild and put into a Chevy P/U. The timing gear cover is pretty much toast. I have 2 Buick V6 engines which appear to have good timing chain covers. They look just like the one off of the V8. Is there any reason you know of why they would not interchange? Thanks in advance for any advice and by the way I thought I knew alot about various engines, but usually wind up learning something from your posts. Keep up the good work.

 

I had a '71 Buick GS350 as my daily driver right before I finished my shoebox. It ran pretty damn hard, but I don't think I would have necessarily considered it fast. It had a mild cam and a q-jet, nothing fancy.

The Buick 350s are good motors and are usually dirt cheap...In fact, I had one that I came very close to putting in my shoebox before I stumbled up on the Chevy that's currently in it. I bought a complete running '76 Regal for $100. I decided the SBC was a better choice, however.

Not to knock the Buick 350, but for my money, the 455 Buick is where it's at. They are torque monsters with no mods whatsoever, and respond extremely well to cam swaps and intake changes. You can even get aluminum heads for them now.

The initial cost is not that much more than a 350, and when you're finished with it, you'll have a motor that will outrun almost anything on the road. The 455's are also fairly lightweight..weighing in very close to the weight of the SBC.

My 2 cents...

 

Do I understand that the Buick 350 is a bolt in swap for the Olds 307? That would make a lot of those 80's wagons wake up for towing.
With that engine available thru 1981 there have to be a lot of well cared for "Old Mans Cars" laying around cheap.

 

286merc, sorry for the confusion. I should have been more specific about the 307 Olds can be swapped out for a 350/403/455 Olds, same mounts. Not a Buick, unless you get the proper engine and frame mounts for the Buick, then it will bolt in, the Olds and Buick both have the same B-O-P bellhousing pattern. So trans can stay in the car with either swap.

For the question about the 231 timing covers the same as 350, I think you can swap them, but not 100% sure.

 

Thanks Guys...This is an excellent informative post and exactly at the right time ..I am just starting to do up a 70 Buick lesabre convertible.and have been trying to figure out if I could use a 455 in it and run a 200r4 behind it with out having to many modifications to the frame to install it ...I just want to probably run it stock with a 4v and have a little punch with the 200r4 and have the overdrive.. car presently has the 350 but it's tired and I think I found a 455...I would like to be able to dress the engine a little with some clean looking covers..so far I am just in the thinking about what to do ..I am going to look at a 76 this weekend with a 455 in it so as long as I can scoop the whole car this sounds like it should be an easy swap..any suggestions for the 455 as far as the rear end that need to be changed or should I use the rear end from the 455 is it built any better than the one in existing 350 I have now ..I have no idea at this time what the ratio is, anybody?....Thank you for this most excellent post with a wealth of info..that's what makes this place what it is....fatchuk

 

Crclbrnr...My machine shop guy told me that the timing cover from a 350 would fit a 231 V6 and vice-versa, but I haven't actually tried it to know for SURE that they are 100% identical.

The topic came up when he told me about the Turbo V6 seal trick...he said that the 231 V6 used the same cover as the 350 V8, and another Buick guy I worked for said that he was fairly certain that they WOULD interchange, even if not 100% identical.

I know for a fact that the neoprene seal from the V6 fits the 350 cover perfectly, so his info there was right on the money. (And welcomed good news to boot!!).

If there ARE any differences between the V6 and 350 timing covers, I'd think it would be in things such as accesory bolt holes which may or may not affect a custom installation.